(excerpt)
Malloch (1915) described Micropsectra polita (as Tanytarsus politus) from males collected along the banks of Central Dredge Ditch at Easton, Mason County, llIinois. Females of this species were not collected at that time. On 12 February 1974, males, females, and larvae were collected from a small spring-fed seep (Fig. 1) running into Muncie Pond, in Vermilion County, llIinois

Webb, Donald W

English

ValpoScholar

The Great Lakes Entomologist 
Volume 14 
Number 4 - Winter 1981 Number 4 - Winter 
1981 
Article 5 
December 1981 
Redescription of Micropsectra Polita (Diptera: Chironomidae) with 
the Female and Immature Stages 
Donald W. Webb 
Illinois Natural History Survey 
Follow this and additional works at: https://scholar.valpo.edu/tgle 
 Part of the Entomology Commons 
Recommended Citation 
Webb, Donald W. 1981. "Redescription of Micropsectra Polita (Diptera: Chironomidae) with the Female 
and Immature Stages," The Great Lakes Entomologist, vol 14 (4) 
Available at: https://scholar.valpo.edu/tgle/vol14/iss4/5 
This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. 
It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. 
For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 
1981 THE GREAT LAKES ENTOMOLOGIST 185 
REDESCRIPTION OF MICROPSECTRA POLITA 
(DIPTERA: CHIRONOMIDAE) WITH THE 
FEMALE AND IMMATURE STAGES 
Donald W. Webb I 
Malloch (1915) described Micropsectra polita (as Tanytarsus politus) from males collected 
along the banks of Central Dredge Ditch at Easton, Mason County, llIinois. Females of this 
species were not collected at that time. On 12 February 1974, males, females, and larvae 
were collected from a small spring-fed seep (Fig. 1) runn ng into Muncie Pond, in Vermilion 
County, llIinois. Males were easily collected as they swarmed over vegetation along the 
edge of the seep. Females were collected by sweeping nearby vegetation. Larvae were 
collected from fine sand covered by 5-10 cm of water; several specimens were reared 
through to the adult stage. 
Fig. I. Spring-fed seep running into Muncie Pond, 0.5 miles SSE of Muncie, Vermilion County, Illinois. 
The terminology in this paper follows Saether (1980). 
Male. Length 3.5l-4.01, 3.74 0.09 mm (N = 5). Head pale brown, pedicel, tlagel­
lomeres, clypeus, maxillary palps dark brown. Eyes black, dichoptic, facets of equal size, 
glabrous. Coronal triangle broad, 1.0-1.1 times longer than wide; coronal setae absent. 
Scape flattened, ring-shaped, 1.6 times longer than wide; pedicel globose, as long as wide, 
macrosetae absent; flagellomere lengths 0.05~.072, 0.064; 0.030-0.042, 0.032; 0.030; 
0.030-0.036, 0.034; 0.030-0.036,0.035; 0.036-0.042, 0.038; 0.036-0.048, 0.041; 0.042-0.048, 
0.044; 0.042-0.048, 0.044; 0.042-0.048, 0.046; 0.045-0.054, 0.048; 0.048-0.054, 0.050; 0.414­
0.588,0.528 mm. Clypeus broad, 1.4-2.2, 1.7 times wider than long; clypeal setae 16-23, 19. 
I Section of Faunistic Surveys and Insect Identification, Illinois Natural History Survey, Champaign, 
IL 
61820 
1
Webb: Redescription of Micropsectra Polita (Diptera: Chironomida
Published by ValpoScholar, 1981
186 THE GREAT LAKES ENTOMOLOGIST Vol. 14, No.4 
Maxillary palps membranous, cylindrical; length of palpomeres 0.064--0.092, 0.075; 0.058­
0.069, 0.064; 0.156-0.212, 0.193; 0.129-0.161, 0.142; 0.202-0.267, 0.224 mm; setae fuscus, 
elongate, scattered. Inner vertical setae 3-9, 6; outer vertical setae 1-3, 2; frontal and 
postorbital setae absent. Cibarial pump triangular, 3.93-4.80, 4.21 mm long, 4.2 times longer 
than wide. Tentorium 4.41-5.27, 5.03 mm long. 
Thorax pale yellowish brown, vittae dark brown, subshiny; pleura stramineous to dark 
brown ventrally. Antepronotum reduced, subrectangular in lateral view, in dorsal view 
median fissure contiguous posteriorly; antepronotal setae absent. Acrostichial setae 13-22, 
16; 
dorsocentrals 9-13, 
II; prealar setae 3-4,3. Haltere stalk dark brown, capitulum clavate, 
stramineous with 6-8 fine setae on anterior surface. Scutellum dark brown, subshiny, broad­
ly rounded posteriorly; scutellar setae 6-8, 7 in single transverse row. Postnotum dark 
brown. Preepisternal setae absent. 
Wing length 2.14-2.72,2.58 ± 0.11 mm, 4.16 times longer than wide. Membrane hyaline to 
pale yellow; microtrichia absent; macrosetae elongate, covering entire wing; veins pale 
brown. Costa ending anterior to apex of wing, not extending beyond apex of ~+5' Sc 
ending slightly beyond middle of wing, not reaching costa. R-m basal to middle of wing. 
R2+ 3. 
indistinct, lying 
along ~+5' R5 ending at costa anterior to apex f wing. Ml+2 ending 
slightly posterior to apex of wing. Fork of Cu originates distal to r-m, VR 0.96-1.08, 1.02 
Anal vein extends to fork of Cu. Alula reduced, indistinct. Squama small, without marginal 
fringe of setae. 
Legs pale brown, concolor. Fore femur clavate, apex 3.2 times width at base, remaining 
segments linear. Spur on fore tibia 0.030 mm. Combs on middle and hind tibiae contiguous, 
spurs absent. Apical claws on tarsomere 5 simple, paired, dark brown. Pulvilli reduced, 0.5 
times length of apical claws. 
Lengths (in mm) and proportions of legs: 
fe ti tal t~ 
PI 0.979-1.239, 1.141 0.719-0.887,0.832 1.025-1.239, 1.178 0.536-0.658, 0.631 
P2 0.918-1.209, 1.120 
P3 1.148-1.392, 1.312 
0.826-1.040, 0.982 
1.056-1.346, .243 
0.444-0.536, 0.521 
0.689-0.872, 0.780 
0.275-0.352, 0.324 
0.413-0.536, 0.385 
ta3 ta4 t~ LR 
PI 0.428-0.505, 0.484 0.291-0.337,0.328 0.153-0.184, 
O. I75 1.426-1.397, 1.416 
P2 0.230-0.291, 0.269 
P3 
0.337-0.413, 0.390 
0.153-0.199, 
0.181 
0.214-0.26 , 0.245 
0.077-0.122, 0.107 
0.122-0.138, 0.130 
0.538-0.515, 0.531 
0.652-0.648, 0.628 
BV SV 
PI 1.934-1.998 1.657-1.716 
P2 2.977-2.889 3.928-4.196 
P3 2.664-2.680 3.199-3.140 
Abdomen and terminalia (Fig. 2) pale brown; setae dark brown, scattered. Anal point 
short, acute. Superior volsella bulbous, rounded apically with ventral projection narrow, 
extending slightly beyond apex of bulboUS portion. Inferior volsella capitate, apex truncate. 
Medium volsella narrow, elongate, extending beyond apex of inferior volsella; setae on 
basal half elongate, linear, setae on apical half sigmoidal. 
The 
males 
of Micropsectra poUta are very similar to M. dives in the leg ratio of the foreleg, 
but the short, bulbous shape of the superior volsella and the extension of the median volsella 
distal to the apex of the inferior volsella readily separate this species from M. dives. 
Female. Characters similar to male except for following variation. Length 1.99-3.15,2.49 
± 0.19 mm (N = 5). Head pale yellowish brown; vertex, pedicel, and dorsal half of labrum 
dark brown; tlagellomeres pale brown. Coronal triangle broad, 1.2 times longer than wide. 
Pedicel globose (Fig. 3); flagellomere lengths 0.096-0.120, 0.109; 0.084-0.090, 0.085; 0.078­
2
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1981 THE GREAT LAKES ENTOMOLOGIST 187 
0.090,0.085; 0.084-0.090, 0.085; 0.1l4--O.144, 0.127 mm, flagellomeres 1-4 with subapical 
pair of 
hyaline, sclerotized blades, each 0.056 mm in length, apical flagellomere without macrosetae. 
Clypeus broad, 1.4 times wider than long, clypeal setae 20-24. Maxillary palps pale 
yellowish brown; length 
of palpomeres 0.024--0.042, 0.032; 0.036-0.054, 0.043; 0.120­
0.144, 0.134; 0.108-0.144, 0.122; 0.150-0.174, 0.162 mm; setae fuscus, elongate, scattered. 
Inner 
vertical setae fr-7; 
outer vertical setae 2-3. Cibarial pump 0.138 mm long, 0.078 mm 
wide, 
1.7 times 
longer than wide. 
Acrostichial setae 12-15; dorsocentrals 14; prealers 3. Scutellar setae 10-12. 
Wing (Fig. 4) length 2.34-2.71, 2.50 ± 0.06 mm (N = 5), 3.2 times longer than wide. VR 
1.16. 
Figs. 2-5. Micrapseclra palila, Male: (2) genitalia, (SV) superior volsella, (IV) inferior volsella, (MV) 
median volsella; Female: (3) antenna, (4) wing, (5) genitalia, (GcIX) gonacoxite IX, (ee) cercus, 
(Gp VIII) gonapophysis VIII, (R) rami of gonapophysis IX. 
3
Webb: Redescription of Micropsectra Polita (Diptera: Chironomida
Published by ValpoScholar, 1981
188 THE GREAT LAKES ENTOMOLOGIST Vol. 14, No.4 
Spur on 
fore tibia 0.012 mm long. Lengths (in mm) and proportions 
of legs: 
fe 
ti tal 
t~ 
PI 0.949-0.995, 0.972 0.719-0.765, 0.742 1.010-1.025, 1.017 0.551-0.551,0.551 
P2 0.918-1.040, 0.991 p) 
1.071-1.239, 
1.152 
0.857-0.918, 0.887 
1.086-1.224, .163 
0.428-0.490, 0.455 
0.643-0.750, 0.694 
0.275-0.306, 0.291 
0.413-0.459, 0.428 
ta3 ta 4 ta5 LR 
PI 0.398-0.413, 0.405 0.291-0.306, 0.298 0.153-0.153,0.153 1.404-1.340, 1.371 
P2 0.214-0.245, 0.233 p) 
0.321-0.367, 0.347 
0.138-0.168,0.153 
0.184-0.214,0.194 
0.107-0.108, 0.107 
0.122-0.122, 0.122 
0.499-0.534, 0.513 
0.592-0.613, 0.597 
BV SV 
PI 1.922-1.957 1.651-1.717 
P2 2.960-3.001 3.996-4.147 
P3 2.692-2.765 3.284-3.355 
Abdomen pale yellowish brown. Genitalia (Fig. 
5). Gonocoxite IX with 1 seta. Sperma­
theca 
oval to spherical, length 0.072-0.096, 0.078 mm, width 0.048-0.066, 0.056 mm, 
1.39 
times longer than wide. Cercus length 0.060-0.114, 0.092 mm. Ventrolateral lobe of 
gonapophysis VIII broad, setae fine, short. Rami of gonapophysis IX elongate, length 0.198­
0.210, 0.204 mm, posterior fourth clavate. 
Pupa. Length 4.73-4.90, 4.81 mm (N 3). Exuvium pale yellow. Thoracic horn (Fig. 6) 
plumose, with filaments arising dorsally from broad basal shaft, length over 25 times width 
at base. Pre corneal setae 1-2 (Fig. 6) paired, P~ positioned laterally, near base of thoracic 
horn. Cephalic tubercles short, rounded, with single apical macroseta over 7 times length of 
cephalic tubercle. Frontal warts absent. Dorsocentral setae 1-2 paired, close together. 
Dorsocentral setae 3-4, metanotals, prealers, supraalars, postorbitals and verticl setae on 
ocular field absent. Nose of wing sheath short, rounded, pearl row absent. Tergite II (Fig. 7) 
with posterior row of hooks continuous; fine shagreen covering entire tergite. Tergites III-VI 
with pattern of medial spines Of. spinnules (Fig. 7). Segment IV with two filamentous L-setae, 
segment V with three filamentous L-setae. segments VI-VII with four fllamentous L-setae, 
segment VIII with five filamentous L-setae. Segments III-IV with one pair of dorsal setae, 
segments II, V-VI with two pairs of dorsal setae, segment VII with five pairs of dorsal setae, 
dorsal setae absent o segment VIII. Fringe of anal lobe with 35-40, 37 setae. Anal macrosetae 
absent. Posterolateral tubercle on tergite VIII, short, rounded (Fig. 8). 
The pupa of 
Micropsectra paUla 
is distinctive in having a paired medial patch of fine 
spinnules on abdominal tergite VI, and is rea ily separated from M. dives in having the 
paired 
medial patch 
of spines or spinnules on abdominal tergites IV-VI with a narrow 
posteriorlateral extension. 
Larva. Head capsule length 0.383-0.413, 0.407 mm (N = 5), width 0.306-0.337, 0.321 mm, 
1.27 times longer than wide; postoccipital margin invaginated ventrally, V-shaped, extend­
ing anteriorly 0.41 of way from posterior margin of head. Antenna (Fig. 9), length of seg­
ments in mm: 0.200-0.242, 0.226; 0.062-0.076, 0.069; 0.009; 0.009; 0.007; AR 2.41. Width 
of 
basal antennal segment 0.021-0.041, 0.029 mm, 7.8 times longer than wide, 
3.3 times 
length of second segment; distance from base to annular organ 0.154-0.173, 0.162 mm, blade 
at apex 
0.012-0.018, 0.015 mm. Lauterborne organs small, on elongate petiole 0.61 times 
length 
of basal antennal segment, 2.0 times length of second antennal segment. Basal tuber­
cle of antenna broad, subrectangular, 1.2 times longer than wide, with short mediolateral 
spur, 0.014 mm. Mentum (Fig. 10). length 0.051-0.060, 0.057, width 0.094-0.115, 0.102,1.8 
times wider than long, convex anteriorly; median tooth trilobed, five pairs of lateral teeth 
descending in height from median tooth. Ventromental plate narrow (Fig. 10), elongate, 
4
The Great Lakes Entomologist, Vol. 14, No. 4 [1981], Art. 5
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1981 THE GREAT LAKES ENTOMOLOGIST 189 
Figs. 6-8. Micropsectra pollta, pupa: (6) thoracic hom, (Pc 1-3) precomeal setae, (7) abdominal tergites, 
(8) posterolateral tubercle, tergite VIII. 
separated medially by distance less than width of median tooth; length 0.023-0.025, 0.025 
mm, 
width 0.1l7-O.13I, 0.125 mm, 5.0 times wider 
than long; anterior margin smooth, 
striations 
fine. Mandible (Fig. 
ll), length 0.115-0.147,0.134 mm; lateral margin broadly 
rounded, not 
crenulate; mediolateral margin straight, not serrated; apical tooth short, blunt, 0.6 times width of three lateral tee h; seta subdentalis (SSd) narrow, elongate, extending to 
apex of 
apical 
tooth; setae intema plumose, with three basal branches; two lateral setae 
elongate. 
Premandible (Fig. 
12) elongate; length 0.074-0.087,0.081 mm; inner blade broad, 
rounded 
apically; lateral blade narrow, acute, ending before apex 
of inner blade; pre­
mandibular brush broad, 
with numerous fine setae. Setulae 
I large (Fig. 13), pectinate, with 
15-19 teeth. Labrallammella broad (Fig. 13), with 20-22 acute teeth. Pecten epipharyngis 
(Fig. 13) separated into three distinct plates, lateral plates with 6-7 rounded, apical teeth; 
median plate 
with 
4 rounded apical teeth. 
Procercus reduced 
(Fig. 14), broad, 
1.3 times wider than long, slightly raised above 
dorsum of abdomen, 
lightly sclerotized, with seven apical setae, apical claws on posterior prolegs 
simple, falcate. The larva of M. polita is similar toM. dives in having the basal segment of the antenna 3.3 
times longer than the second 
antennal segment, 
but differs from M. dives in lacking a dorsal 
tubercle on 
abdominal segment VIII, and 
in having the mentum with a trilobed median 
tooth. 
5
Webb: Redescription of Micropsectra Polita (Diptera: Chironomida
Published by ValpoScholar, 1981
190 THE GREAT LAKES ENTOMOLOGIST Vol. 14, N 4 
12 
9 
Figs. 9--14. Micrapseclra palila, larva: (9) antenna, (10) mentum and ventromenlal plates, (11) mandible 
(SSd) seta subdentalis, (12) premandible, (13) pecten epipharyngis (Pe). labrallamella (LL), and setulae 
I (SI), (14) procercus. 
LITERATURE CITED 
Malloch, J. R. 1915. The Chironomidae, or midges of Illinois with particular reference to the 
species occurring in the Illinois River. Bull. Illinois Lab. Nat. Hist. 10:275-543. 
Saether, 
O. A. 
1980. Glossary of chironomid morphology terminology (Diptera: Chiron­
omidae). Entomol. Scand. Suppl. 14: 1-51. 
6
The Great Lakes Entomologist, Vol. 14, No. 4 [1981], Art. 5
https://scholar.valpo.edu/tgle/vol14/iss4/5

Redescription of \u3ci\u3eMicropsectra Polita\u3c/i\u3e (Diptera: Chironomidae) with the Female and Immature Stages

Donald W Webb

Crossref

 (Diptera: Chironomidae) with the Female and Immature Stages

Valparaiso University

The Great Lakes Entomologist Volume 14 Number 4 - Winter 1981 Number 4 - Winter 1981 Article 5 December 1981 Redescription of Micropsectra Polita (Diptera: Chironomidae) with the Female and Immature Stages Donald W. Webb Illinois Natural History Survey Follow this and additional works at: https://scholar.valpo.edu/tgle Part of the Entomology Commons Recommended Citation Webb, Donald W. 1981. "Redescription of Micropsectra Polita (Diptera: Chironomidae) with the Female and Immature Stages," The Great Lakes Entomologist, vol 14 (4) Available at: https://scholar.valpo.edu/tgle/vol14/iss4/5 This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 1981 THE GREAT LAKES ENTOMOLOGIST 185 REDESCRIPTION OF MICROPSECTRA POLITA (DIPTERA: CHIRONOMIDAE) WITH THE FEMALE AND IMMATURE STAGES Donald W. Webb I Malloch (1915) described Micropsectra polita (as Tanytarsus politus) from males collected along the banks of Central Dredge Ditch at Easton, Mason County, llIinois. Females of this species were not collected at that time. On 12 February 1974, males, females, and larvae were collected from a small spring-fed seep (Fig. 1) runn ng into Muncie Pond, in Vermilion County, llIinois. Males were easily collected as they swarmed over vegetation along the edge of the seep. Females were collected by sweeping nearby vegetation. Larvae were collected from fine sand covered by 5-10 cm of water; several specimens were reared through to the adult stage. Fig. I. Spring-fed seep running into Muncie Pond, 0.5 miles SSE of Muncie, Vermilion County, Illinois. The terminology in this paper follows Saether (1980). Male. Length 3.5l-4.01, 3.74 0.09 mm (N = 5). Head pale brown, pedicel, tlagel­lomeres, clypeus, maxillary palps dark brown. Eyes black, dichoptic, facets of equal size, glabrous. Coronal triangle broad, 1.0-1.1 times longer than wide; coronal setae absent. Scape flattened, ring-shaped, 1.6 times longer than wide; pedicel globose, as long as wide, macrosetae absent; flagellomere lengths 0.05~.072, 0.064; 0.030-0.042, 0.032; 0.030; 0.030-0.036, 0.034; 0.030-0.036,0.035; 0.036-0.042, 0.038; 0.036-0.048, 0.041; 0.042-0.048, 0.044; 0.042-0.048, 0.044; 0.042-0.048, 0.046; 0.045-0.054, 0.048; 0.048-0.054, 0.050; 0.414­0.588,0.528 mm. Clypeus broad, 1.4-2.2, 1.7 times wider than long; clypeal setae 16-23, 19. I Section of Faunistic Surveys and Insect Identification, Illinois Natural History Survey, Champaign, IL 61820 1Webb: Redescription of Micropsectra Polita (Diptera: ChironomidaPublished by ValpoScholar, 1981186 THE GREAT LAKES ENTOMOLOGIST Vol. 14, No.4 Maxillary palps membranous, cylindrical; length of palpomeres 0.064--0.092, 0.075; 0.058­0.069, 0.064; 0.156-0.212, 0.193; 0.129-0.161, 0.142; 0.202-0.267, 0.224 mm; setae fuscus, elongate, scattered. Inner vertical setae 3-9, 6; outer vertical setae 1-3, 2; frontal and postorbital setae absent. Cibarial pump triangular, 3.93-4.80, 4.21 mm long, 4.2 times longer than wide. Tentorium 4.41-5.27, 5.03 mm long. Thorax pale yellowish brown, vittae dark brown, subshiny; pleura stramineous to dark brown ventrally. Antepronotum reduced, subrectangular in lateral view, in dorsal view median fissure contiguous posteriorly; antepronotal setae absent. Acrostichial setae 13-22, 16; dorsocentrals 9-13, II; prealar setae 3-4,3. Haltere stalk dark brown, capitulum clavate, stramineous with 6-8 fine setae on anterior surface. Scutellum dark brown, subshiny, broad­ly rounded posteriorly; scutellar setae 6-8, 7 in single transverse row. Postnotum dark brown. Preepisternal setae absent. Wing length 2.14-2.72,2.58 ± 0.11 mm, 4.16 times longer than wide. Membrane hyaline to pale yellow; microtrichia absent; macrosetae elongate, covering entire wing; veins pale brown. Costa ending anterior to apex of wing, not extending beyond apex of ~+5' Sc ending slightly beyond middle of wing, not reaching costa. R-m basal to middle of wing. R2+ 3. indistinct, lying along ~+5' R5 ending at costa anterior to apex f wing. Ml+2 ending slightly posterior to apex of wing. Fork of Cu originates distal to r-m, VR 0.96-1.08, 1.02 Anal vein extends to fork of Cu. Alula reduced, indistinct. Squama small, without marginal fringe of setae. Legs pale brown, concolor. Fore femur clavate, apex 3.2 times width at base, remaining segments linear. Spur on fore tibia 0.030 mm. Combs on middle and hind tibiae contiguous, spurs absent. Apical claws on tarsomere 5 simple, paired, dark brown. Pulvilli reduced, 0.5 times length of apical claws. Lengths (in mm) and proportions of legs: fe ti tal t~ PI 0.979-1.239, 1.141 0.719-0.887,0.832 1.025-1.239, 1.178 0.536-0.658, 0.631 P2 0.918-1.209, 1.120 P3 1.148-1.392, 1.312 0.826-1.040, 0.982 1.056-1.346, .243 0.444-0.536, 0.521 0.689-0.872, 0.780 0.275-0.352, 0.324 0.413-0.536, 0.385 ta3 ta4 t~ LR PI 0.428-0.505, 0.484 0.291-0.337,0.328 0.153-0.184, O. I75 1.426-1.397, 1.416 P2 0.230-0.291, 0.269 P3 0.337-0.413, 0.390 0.153-0.199, 0.181 0.214-0.26 , 0.245 0.077-0.122, 0.107 0.122-0.138, 0.130 0.538-0.515, 0.531 0.652-0.648, 0.628 BV SV PI 1.934-1.998 1.657-1.716 P2 2.977-2.889 3.928-4.196 P3 2.664-2.680 3.199-3.140 Abdomen and terminalia (Fig. 2) pale brown; setae dark brown, scattered. Anal point short, acute. Superior volsella bulbous, rounded apically with ventral projection narrow, extending slightly beyond apex of bulboUS portion. Inferior volsella capitate, apex truncate. Medium volsella narrow, elongate, extending beyond apex of inferior volsella; setae on basal half elongate, linear, setae on apical half sigmoidal. The males of Micropsectra poUta are very similar to M. dives in the leg ratio of the foreleg, but the short, bulbous shape of the superior volsella and the extension of the median volsella distal to the apex of the inferior volsella readily separate this species from M. dives. Female. Characters similar to male except for following variation. Length 1.99-3.15,2.49 ± 0.19 mm (N = 5). Head pale yellowish brown; vertex, pedicel, and dorsal half of labrum dark brown; tlagellomeres pale brown. Coronal triangle broad, 1.2 times longer than wide. Pedicel globose (Fig. 3); flagellomere lengths 0.096-0.120, 0.109; 0.084-0.090, 0.085; 0.078­2The Great Lakes Entomologist, Vol. 14, No. 4 [1981], Art. 5https://scholar.valpo.edu/tgle/vol14/iss4/51981 THE GREAT LAKES ENTOMOLOGIST 187 0.090,0.085; 0.084-0.090, 0.085; 0.1l4--O.144, 0.127 mm, flagellomeres 1-4 with subapical pair of hyaline, sclerotized blades, each 0.056 mm in length, apical flagellomere without macrosetae. Clypeus broad, 1.4 times wider than long, clypeal setae 20-24. Maxillary palps pale yellowish brown; length of palpomeres 0.024--0.042, 0.032; 0.036-0.054, 0.043; 0.120­0.144, 0.134; 0.108-0.144, 0.122; 0.150-0.174, 0.162 mm; setae fuscus, elongate, scattered. Inner vertical setae fr-7; outer vertical setae 2-3. Cibarial pump 0.138 mm long, 0.078 mm wide, 1.7 times longer than wide. Acrostichial setae 12-15; dorsocentrals 14; prealers 3. Scutellar setae 10-12. Wing (Fig. 4) length 2.34-2.71, 2.50 ± 0.06 mm (N = 5), 3.2 times longer than wide. VR 1.16. Figs. 2-5. Micrapseclra palila, Male: (2) genitalia, (SV) superior volsella, (IV) inferior volsella, (MV) median volsella; Female: (3) antenna, (4) wing, (5) genitalia, (GcIX) gonacoxite IX, (ee) cercus, (Gp VIII) gonapophysis VIII, (R) rami of gonapophysis IX. 3Webb: Redescription of Micropsectra Polita (Diptera: ChironomidaPublished by ValpoScholar, 1981188 THE GREAT LAKES ENTOMOLOGIST Vol. 14, No.4 Spur on fore tibia 0.012 mm long. Lengths (in mm) and proportions of legs: fe ti tal t~ PI 0.949-0.995, 0.972 0.719-0.765, 0.742 1.010-1.025, 1.017 0.551-0.551,0.551 P2 0.918-1.040, 0.991 p) 1.071-1.239, 1.152 0.857-0.918, 0.887 1.086-1.224, .163 0.428-0.490, 0.455 0.643-0.750, 0.694 0.275-0.306, 0.291 0.413-0.459, 0.428 ta3 ta 4 ta5 LR PI 0.398-0.413, 0.405 0.291-0.306, 0.298 0.153-0.153,0.153 1.404-1.340, 1.371 P2 0.214-0.245, 0.233 p) 0.321-0.367, 0.347 0.138-0.168,0.153 0.184-0.214,0.194 0.107-0.108, 0.107 0.122-0.122, 0.122 0.499-0.534, 0.513 0.592-0.613, 0.597 BV SV PI 1.922-1.957 1.651-1.717 P2 2.960-3.001 3.996-4.147 P3 2.692-2.765 3.284-3.355 Abdomen pale yellowish brown. Genitalia (Fig. 5). Gonocoxite IX with 1 seta. Sperma­theca oval to spherical, length 0.072-0.096, 0.078 mm, width 0.048-0.066, 0.056 mm, 1.39 times longer than wide. Cercus length 0.060-0.114, 0.092 mm. Ventrolateral lobe of gonapophysis VIII broad, setae fine, short. Rami of gonapophysis IX elongate, length 0.198­0.210, 0.204 mm, posterior fourth clavate. Pupa. Length 4.73-4.90, 4.81 mm (N 3). Exuvium pale yellow. Thoracic horn (Fig. 6) plumose, with filaments arising dorsally from broad basal shaft, length over 25 times width at base. Pre corneal setae 1-2 (Fig. 6) paired, P~ positioned laterally, near base of thoracic horn. Cephalic tubercles short, rounded, with single apical macroseta over 7 times length of cephalic tubercle. Frontal warts absent. Dorsocentral setae 1-2 paired, close together. Dorsocentral setae 3-4, metanotals, prealers, supraalars, postorbitals and verticl setae on ocular field absent. Nose of wing sheath short, rounded, pearl row absent. Tergite II (Fig. 7) with posterior row of hooks continuous; fine shagreen covering entire tergite. Tergites III-VI with pattern of medial spines Of. spinnules (Fig. 7). Segment IV with two filamentous L-setae, segment V with three filamentous L-setae. segments VI-VII with four fllamentous L-setae, segment VIII with five filamentous L-setae. Segments III-IV with one pair of dorsal setae, segments II, V-VI with two pairs of dorsal setae, segment VII with five pairs of dorsal setae, dorsal setae absent o segment VIII. Fringe of anal lobe with 35-40, 37 setae. Anal macrosetae absent. Posterolateral tubercle on tergite VIII, short, rounded (Fig. 8). The pupa of Micropsectra paUla is distinctive in having a paired medial patch of fine spinnules on abdominal tergite VI, and is rea ily separated from M. dives in having the paired medial patch of spines or spinnules on abdominal tergites IV-VI with a narrow posteriorlateral extension. Larva. Head capsule length 0.383-0.413, 0.407 mm (N = 5), width 0.306-0.337, 0.321 mm, 1.27 times longer than wide; postoccipital margin invaginated ventrally, V-shaped, extend­ing anteriorly 0.41 of way from posterior margin of head. Antenna (Fig. 9), length of seg­ments in mm: 0.200-0.242, 0.226; 0.062-0.076, 0.069; 0.009; 0.009; 0.007; AR 2.41. Width of basal antennal segment 0.021-0.041, 0.029 mm, 7.8 times longer than wide, 3.3 times length of second segment; distance from base to annular organ 0.154-0.173, 0.162 mm, blade at apex 0.012-0.018, 0.015 mm. Lauterborne organs small, on elongate petiole 0.61 times length of basal antennal segment, 2.0 times length of second antennal segment. Basal tuber­cle of antenna broad, subrectangular, 1.2 times longer than wide, with short mediolateral spur, 0.014 mm. Mentum (Fig. 10). length 0.051-0.060, 0.057, width 0.094-0.115, 0.102,1.8 times wider than long, convex anteriorly; median tooth trilobed, five pairs of lateral teeth descending in height from median tooth. Ventromental plate narrow (Fig. 10), elongate, 4The Great Lakes Entomologist, Vol. 14, No. 4 [1981], Art. 5https://scholar.valpo.edu/tgle/vol14/iss4/51981 THE GREAT LAKES ENTOMOLOGIST 189 Figs. 6-8. Micropsectra pollta, pupa: (6) thoracic hom, (Pc 1-3) precomeal setae, (7) abdominal tergites, (8) posterolateral tubercle, tergite VIII. separated medially by distance less than width of median tooth; length 0.023-0.025, 0.025 mm, width 0.1l7-O.13I, 0.125 mm, 5.0 times wider than long; anterior margin smooth, striations fine. Mandible (Fig. ll), length 0.115-0.147,0.134 mm; lateral margin broadly rounded, not crenulate; mediolateral margin straight, not serrated; apical tooth short, blunt, 0.6 times width of three lateral tee h; seta subdentalis (SSd) narrow, elongate, extending to apex of apical tooth; setae intema plumose, with three basal branches; two lateral setae elongate. Premandible (Fig. 12) elongate; length 0.074-0.087,0.081 mm; inner blade broad, rounded apically; lateral blade narrow, acute, ending before apex of inner blade; pre­mandibular brush broad, with numerous fine setae. Setulae I large (Fig. 13), pectinate, with 15-19 teeth. Labrallammella broad (Fig. 13), with 20-22 acute teeth. Pecten epipharyngis (Fig. 13) separated into three distinct plates, lateral plates with 6-7 rounded, apical teeth; median plate with 4 rounded apical teeth. Procercus reduced (Fig. 14), broad, 1.3 times wider than long, slightly raised above dorsum of abdomen, lightly sclerotized, with seven apical setae, apical claws on posterior prolegs simple, falcate. The larva of M. polita is similar toM. dives in having the basal segment of the antenna 3.3 times longer than the second antennal segment, but differs from M. dives in lacking a dorsal tubercle on abdominal segment VIII, and in having the mentum with a trilobed median tooth. 5Webb: Redescription of Micropsectra Polita (Diptera: ChironomidaPublished by ValpoScholar, 1981190 THE GREAT LAKES ENTOMOLOGIST Vol. 14, N 4 12 9 Figs. 9--14. Micrapseclra palila, larva: (9) antenna, (10) mentum and ventromenlal plates, (11) mandible (SSd) seta subdentalis, (12) premandible, (13) pecten epipharyngis (Pe). labrallamella (LL), and setulae I (SI), (14) procercus. LITERATURE CITED Malloch, J. R. 1915. The Chironomidae, or midges of Illinois with particular reference to the species occurring in the Illinois River. Bull. Illinois Lab. Nat. Hist. 10:275-543. Saether, O. A. 1980. Glossary of chironomid morphology terminology (Diptera: Chiron­omidae). Entomol. Scand. Suppl. 14: 1-51. 6The Great Lakes Entomologist, Vol. 14, No. 4 [1981], Art. 5https://scholar.valpo.edu/tgle/vol14/iss4/5

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Redescription of \u3ci\u3eMicropsectra Polita\u3c/i\u3e (Diptera: Chironomidae) with the Female and Immature Stages

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