Lophodiplosis trifida Gagné, an Australian gall midge on paperbark, Melaleuca quinquenervia (Myrtaceae), is a recent release in southern Florida for the biological control of that host. The larval stage is described for the first time and compared to that of other Lophodiplosis species. Photos of galls and illustrations of larvae are provided. Second and third instars of L. trifida are unusual among Cecidomyiidae for the lack of setae on most papillae

Brown, Bradley T.

Center, Ted D.

Gagne, Raymond

Pratt, Paul D.

Purcell, Matthew F.

Wright, Susan

English

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University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
USDA Systematic Entomology Laboratory Entomology Collections, Miscellaneous 
12-2009 
Description of the Larva of Lophodiplosis trifida, an Australian 
Gall Midge (Diptera: Cecidomyiidae) and Biocontrol Agent of 
Paperbark in Florida, USA 
Raymond Gagne 
Systematic Entomology Laboratory, PSI, Agricultural Research Service, USDA, c/o U. S. National Museum 
NHB 168, P.O. Box 37012, Washington, DC 20013-7012, USA, raymond.gagne@ars.usda.gov 
Susan Wright 
Invasive Plant Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, P.O. 
Box 147100, Gainesville, FL 32614-7100, USA, susan.wright@ars.usda.gov 
Matthew F. Purcell 
Australian Biological Control Laboratory, Agricultural Research Service, U.S. Department of Agriculture, 
CSIRO Entomology, 120 Meiers Road, Indooroopilly, Queensland, Australia 4068, 
matthew.purcell@csiro.au 
Bradley T. Brown 
Australian Biological Control Laboratory, Agricultural Research Service, U.S. Department of Agriculture, 
CSIRO Entomology, 120 Meiers Road, Indooroopilly, Queensland, Australia 4068, bradley.brown@csiro.au 
Paul D. Pratt 
Invasive Plant Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Ft. 
Lauderdale, FL, 33314, USA, paul.pratt@ars.usda.gov 
See next page for additional authors 
Follow this and additional works at: https://digitalcommons.unl.edu/systentomologyusda 
 Part of the Entomology Commons 
Gagne, Raymond; Wright, Susan; Purcell, Matthew F.; Brown, Bradley T.; Pratt, Paul D.; and Center, Ted D., 
"Description of the Larva of Lophodiplosis trifida, an Australian Gall Midge (Diptera: Cecidomyiidae) and 
Biocontrol Agent of Paperbark in Florida, USA" (2009). USDA Systematic Entomology Laboratory. 17. 
https://digitalcommons.unl.edu/systentomologyusda/17 
This Article is brought to you for free and open access by the Entomology Collections, Miscellaneous at 
DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USDA Systematic 
Entomology Laboratory by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. 
Authors 
Raymond Gagne, Susan Wright, Matthew F. Purcell, Bradley T. Brown, Paul D. Pratt, and Ted D. Center 
This article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/
systentomologyusda/17 
Gagné et al: Description of Lophodiplosis trifida Larva 593
DESCRIPTION OF THE LARVA OF LOPHODIPLOSIS TRIFIDA, AN
AUSTRALIAN GALL MIDGE (DIPTERA: CECIDOMYIIDAE) AND 
BIOCONTROL AGENT OF PAPERBARK IN FLORIDA, USA
RAYMOND J. GAGNÉ1, SUSAN A. WRIGHT2, MATTHEW F. PURCELL3, BRADLEY T. BROWN3, PAUL D. PRATT4
AND TED D. CENTER4
1Systematic Entomology Laboratory, PSI, Agricultural Research Service, U.S. Department of Agriculture,
c/o Smithsonian Institution MRC-168, P.O. Box 37012, Washington, DC 20013-7012, USA 
E-mail: raymond.gagne@ars.usda.gov
2Invasive Plant Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture,
P.O. Box 147100, Gainesville, FL 32614-7100, USA
E-mail: susan.wright@ars.usda.gov
3Australian Biological Control Laboratory, Agricultural Research Service, U.S. Department of Agriculture,
CSIRO Entomology, 120 Meiers Road, Indooroopilly, Queensland, Australia 4068
E-mail: matthew.purcell@csiro.au; bradley.brown@csiro.au
4Invasive Plant Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture,
Ft. Lauderdale, FL, 33314, USA
E-mail: paul.pratt@ars.usda.gov; ted.center@ars.usda.gov
ABSTRACT
Lophodiplosis trifida Gagné, an Australian gall midge on paperbark, Melaleuca quinque-
nervia (Myrtaceae), is a recent release in southern Florida for the biological control of that
host. The larval stage is described for the first time and compared to that of other Lopho-
diplosis species. Photos of galls and illustrations of larvae are provided. Second and third in-
stars of L. trifida are unusual among Cecidomyiidae for the lack of setae on most papillae.
Key Words: Melaleuca, biological control, bud gall, cecidomyiid
RESUMEN
Lophodiplosis trifida Gagné, una mosquita de agalla sobre Melaleuca quinquenervia (Myr-
taceae) de origen Australiano, fue recién liberada en el sur del estado de Florida para el con-
trol biológico de este hospedero. Se describe el estadio larval por primera vez y se compara
contra larvas de otras especies de Lophodiplosis. Se provee fotos de las agallas e ilustracio-
nes de las larvas. El segundo y tercer estadio de L. trifida no son comunes entre los Cecido-
myiidae por la falta de setas sobre la mayoría de las papilae.
Lophodiplosis trifida Gagné has been success-
fully introduced into southern Florida to aid in the
control of paperbark, Melaleuca quinquenervia
(Myrtaceae) (P. D. Pratt, unpublished). This insect
was initially described as one of 5 Lophodiplosis
species reared from Melaleuca spp. in the vicinity of
Townsville, Qld., Australia (Gagné et al. 1997). No
further species has been added to Lophodiplosis
and, except for L. trifida in Florida, the genus is still
known only from eastern Australia. The other 4 spe-
cies, Lophodiplosis bidentata Gagné, Lophodiplosis
cornuata Gagné, Lophodiplosis indentata Gagné,
and Lophodiplosis denticulata Gagné, were taken
from separate and distinctive galls of paperbark.
Lophodiplosis trifida was initially thought to be an
inquiline in galls of 3 of the other species because it
was reared in association with them but not associ-
ated with any particular distinctive gall of its own
(Gagné et al. 1997). Subsequent observations in the
vicinity of Brisbane, Qld., showed that L. trifida
forms separate, often very prominent galls (Figs. 1-
4) in young shoots (Purcell et al. 2007). In the earlier
situation in Townsville, stem galls of L. trifida galls
were evidently inconspicuous, perhaps containing
only 1 or 2 larvae, and had presumably been
masked by galls of the other Lophodiplosis species
and associated plant tissue in rearing cages. The
larval stage of L. trifida was not described initially,
unlike those of 3 of the other species of Lophodiplo-
sis (that of L. denticulata remains undescribed).
Now that L. trifida has taken on biological control
importance, we take this opportunity to describe the
instars for future identification.
MATERIALS AND METHODS
Larvae of known L. trifida, as determined from
adults and pupae reared in quarantine in Ft. Lau-
derdale, FL, were removed from paperbark shoot
galls in various stages of growth. Specimens were
the progeny, many generations removed, of material
originally sent from Indooroopilly, Qld., Australia.
Published in Florida Entomologist 92(4) December 2009
594 Florida Entomologist 92(4) December 2009
Figs. 1-4. Shoots of paperbark galled by Lophodiplosis trifida. 1, Galled young, soft shoot. 2, Longitudinal section
of same largely filled with spherical larval cells containing first instars. 3, Older, woody gall with exit holes, the ar-
rows indicating pupal exuviae still attached. 4, Same, longitudinal section, the topmost cell with pupa still inside.
Gagné et al: Description of Lophodiplosis trifida Larva 595
Specimens were placed on slides for viewing in ac-
cordance with the method outlined in Gagné (1989).
Other specimens were critical-point dried and
placed on SEM stubs. Terminology for larval mor-
phology follows that in Gagné (1989).
Description of larva of L. trifida
Third Instar (Figs. 5-12)
Length, 1.3-2.0 mm (n = 10). Body cylindrical,
spindleform. Head capsule hemispherical, with
Figs. 5-9. Lophodiplosis trifida, third instar. 5, Entire larva (dorsolateral). 6, Anterior segments (anteroventral).
7, First thoracic segment with details of spatula and papillae (ventral). 8, Posterior segments showing anus at cen-
ter of terminal segment (lateroventral). 9, Detail of eighth and terminal segments (laterodorsal). Abbreviations: lp
= triplets of lateral papillae; spat = spatula; spir = spiracle; tp = terminal papillae.
596 Florida Entomologist 92(4) December 2009
apodemes as long as capsule; antennae short, as
long as wide. Spiracles present on prothorax and
on first through eighth abdominal segments. In-
tegument with horizontal rows of minute spicules
ventrally on anterior third of 2nd and 3rd thoracic
and all abdominal segments, remainder smooth if
not weakly and irregularly lined. Spatula (Figs. 6,
11) widest posteriorly when fully sclerotized, with
long shaft, anteriorly with 2 large, triangular
teeth and a shorter tooth between. Full comple-
ment of papillae present except only 2 pairs on
terminal segment, 1 corniform, the other seti-
form. Setae present on 2 of 3 of each of the 4
groups of lateral papillae and on 1 of the pairs of
terminal papillae.
Second Instar (Figs. 13-14)
Length, 0.6-0.9 mm (n = 10). Body shape, head,
spiracles, integument and papillae as for third in-
star. Spatula present, short, the acutely triangu-
lar anterior tooth up to half length of shaft. As
with third instar, full complement of papillae is
present except for 2 pairs on terminal segment
Figs. 10-15. Lophodiplosis trifida. 10-12, Third instar: 10, entire larva (dorsal), showing position of sternal spat-
ula on venter; 11, detail of anterior segments with inset showing 2× detail of lateral papillae (ventral); 12, detail of
posterior segments (dorsal). 13-14, Second instar: 13, entire larva (dorsal view), showing position of sternal spatula
on venter; 14, sternal spatula (ventral). 15, First instar, eighth and terminal segments (laterodorsal).
Gagné et al: Description of Lophodiplosis trifida Larva 597
and setae present on only 2 of 3 of each of the 4
groups of lateral papillae and on 1 pair of termi-
nal papillae.
First Instar (Fig. 15)
Length, 0.3-0.5 mm (n = 10). Body shape, head,
and integument as for second and third instars.
Spiracles present only on prothorax and eighth
abdominal segment. Spatula absent. Presence of
papillae as for second and third instars except
that pleural and dorsal papillae and the non-set-
ose pair of terminal papillae of second and third
instars all with minute seta.
Comments on Larval Stage of L. trifida
The first and second instars of this species are
unusual among Cecidomyiidae for the almost
complete absence of papillar setae. Setae occur on
only 2 papillae in each of the 4 sets of lateral trip-
lets and on 2 terminal papillae. The first instar, on
the other hand, has tiny setae, no longer than the
diameter of their papillae, on all pleural and dor-
sal papillae, in addition to the setae already men-
tioned for the third and second instars. The only
other example known of the lack of papillar setae
generally is the genus Caryomyia, a North Amer-
ican genus, in which most of species completely
lack papillar setae, even those on the lateral and
terminal papillae (Gagné 2008). The integument
is remarkably smooth in L. trifida, with the an-
teroventral horizontal bands of spicules the only
sculpturing.
DISCUSSION
The 5 species originally placed in Lophodiplo-
sis come from simple to complex galls of Mela-
leuca spp. (Gagné et al. 1997). These species are
an eclectic mix that, besides having a host genus
in common, share the distinguishing pupal char-
acter of vertexal extensions that are evidently
used in cutting through gall tissue prior to adult
emergence. Many gall midges have variously
shaped prominences on the head for that purpose,
but they are almost always extensions of the an-
tennal bases, not of the vertex. Larvae of Lopho-
diplosis are diverse, but this is not unusual in
genera with a variety of gall shapes (Gagné 2008).
Larvae of L. trifida are unique in Lophodiplosis
for the lack of setae on most papillae, their long,
narrow, tridentate spatula in the third instar, and
mostly smooth integument. The other species of
Lophodiplosis for which larvae are known, L. bi-
dentata Gagné, L. cornuata Gagné, and L. inden-
tata Gagné, have short setae on most papillae, a
short, wide, bidentate spatula, and a rugose in-
tegument. The type species, L. indentata, and L.
trifida both have only 4 papillae on the terminal
segment, but all 4 papillae have setae on L. inden-
tata while only 2 have setae on L. trifida. Both
species have a spatula in the second instar. In gall
midges, a second instar spatula occurs only in
some gall-making genera where it seems to have
arisen de novo in each of the genera where it ap-
pears (Gagné 2008).
ACKNOWLEDGMENTS
We thank P. Malikul for making the slide prepara-
tions, Scott D. Whittaker, SEM Laboratory Manager,
Smithsonian Institution for assistance with the scan-
ning electron microscope, Diana Marquez for electroni-
cally arranging the photos and drawings onto plates,
and James A. Lollis and Elizabeth D. Mattison for assis-
tance in collecting galls and larvae, and the South Flor-
ida Water Management District for financial support to
this project. We are grateful also to Keith M. Harris,
Woking, Surrey, United Kingdom, David A. Nickle and
Allen L. Norrbom, Systematic Entomology Laboratory,
and 2 anonymous reviewers for critical comments on
the manuscript.
REFERENCES CITED
GAGNÉ, R. J. 1989. The Plant-Feeding Gall Midges of
North America. Cornell University Press, Ithaca,
New York. xiii & 355 pp. and 4 pls.
GAGNÉ, R. J. 2008. The gall midges (Diptera: Cecidomyi-
idae) of hickories (Juglandaceae: Carya). Mem.
American Entomol. Soc. 48: 1-147.
GAGNÉ, R. J., BALCIUNAS, J. K., AND BURROWS, D. W.
1997. Six new species of gall midges (Diptera: Cecid-
omyiidae) from Melaleuca (Myrtaceae) in Australia.
Proc. Entomol. Soc. Washington 99: 312-334.
PURCELL, M. F., WINEWRITER (SIC! FOR WINERITER),
AND S. A., BROWN, B. T. 2007. Lophodiplosis trifida
Gagné (Diptera: Cecidomyiidae), a stem-galling
midge with potential as a biological control agent of
Melaleuca quinquenervia (Myrtaceae). Australian
Entomol. 34: 123-125.


Description of the Larva of \u3ci\u3eLophodiplosis trifida\u3c/i\u3e, an Australian Gall Midge (Diptera: Cecidomyiidae) and Biocontrol Agent of Paperbark in Florida, USA

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln USDA Systematic Entomology Laboratory Entomology Collections, Miscellaneous 12-2009 Description of the Larva of Lophodiplosis trifida, an Australian Gall Midge (Diptera: Cecidomyiidae) and Biocontrol Agent of Paperbark in Florida, USA Raymond Gagne Systematic Entomology Laboratory, PSI, Agricultural Research Service, USDA, c/o U. S. National Museum NHB 168, P.O. Box 37012, Washington, DC 20013-7012, USA, raymond.gagne@ars.usda.gov Susan Wright Invasive Plant Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, P.O. Box 147100, Gainesville, FL 32614-7100, USA, susan.wright@ars.usda.gov Matthew F. Purcell Australian Biological Control Laboratory, Agricultural Research Service, U.S. Department of Agriculture, CSIRO Entomology, 120 Meiers Road, Indooroopilly, Queensland, Australia 4068, matthew.purcell@csiro.au Bradley T. Brown Australian Biological Control Laboratory, Agricultural Research Service, U.S. Department of Agriculture, CSIRO Entomology, 120 Meiers Road, Indooroopilly, Queensland, Australia 4068, bradley.brown@csiro.au Paul D. Pratt Invasive Plant Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Ft. Lauderdale, FL, 33314, USA, paul.pratt@ars.usda.gov See next page for additional authors Follow this and additional works at: https://digitalcommons.unl.edu/systentomologyusda  Part of the Entomology Commons Gagne, Raymond; Wright, Susan; Purcell, Matthew F.; Brown, Bradley T.; Pratt, Paul D.; and Center, Ted D., "Description of the Larva of Lophodiplosis trifida, an Australian Gall Midge (Diptera: Cecidomyiidae) and Biocontrol Agent of Paperbark in Florida, USA" (2009). USDA Systematic Entomology Laboratory. 17. https://digitalcommons.unl.edu/systentomologyusda/17 This Article is brought to you for free and open access by the Entomology Collections, Miscellaneous at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USDA Systematic Entomology Laboratory by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Authors Raymond Gagne, Susan Wright, Matthew F. Purcell, Bradley T. Brown, Paul D. Pratt, and Ted D. Center This article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/systentomologyusda/17 Gagné et al: Description of Lophodiplosis trifida Larva 593DESCRIPTION OF THE LARVA OF LOPHODIPLOSIS TRIFIDA, ANAUSTRALIAN GALL MIDGE (DIPTERA: CECIDOMYIIDAE) AND BIOCONTROL AGENT OF PAPERBARK IN FLORIDA, USARAYMOND J. GAGNÉ1, SUSAN A. WRIGHT2, MATTHEW F. PURCELL3, BRADLEY T. BROWN3, PAUL D. PRATT4AND TED D. CENTER41Systematic Entomology Laboratory, PSI, Agricultural Research Service, U.S. Department of Agriculture,c/o Smithsonian Institution MRC-168, P.O. Box 37012, Washington, DC 20013-7012, USA E-mail: raymond.gagne@ars.usda.gov2Invasive Plant Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture,P.O. Box 147100, Gainesville, FL 32614-7100, USAE-mail: susan.wright@ars.usda.gov3Australian Biological Control Laboratory, Agricultural Research Service, U.S. Department of Agriculture,CSIRO Entomology, 120 Meiers Road, Indooroopilly, Queensland, Australia 4068E-mail: matthew.purcell@csiro.au; bradley.brown@csiro.au4Invasive Plant Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture,Ft. Lauderdale, FL, 33314, USAE-mail: paul.pratt@ars.usda.gov; ted.center@ars.usda.govABSTRACTLophodiplosis trifida Gagné, an Australian gall midge on paperbark, Melaleuca quinque-nervia (Myrtaceae), is a recent release in southern Florida for the biological control of thathost. The larval stage is described for the first time and compared to that of other Lopho-diplosis species. Photos of galls and illustrations of larvae are provided. Second and third in-stars of L. trifida are unusual among Cecidomyiidae for the lack of setae on most papillae.Key Words: Melaleuca, biological control, bud gall, cecidomyiidRESUMENLophodiplosis trifida Gagné, una mosquita de agalla sobre Melaleuca quinquenervia (Myr-taceae) de origen Australiano, fue recién liberada en el sur del estado de Florida para el con-trol biológico de este hospedero. Se describe el estadio larval por primera vez y se comparacontra larvas de otras especies de Lophodiplosis. Se provee fotos de las agallas e ilustracio-nes de las larvas. El segundo y tercer estadio de L. trifida no son comunes entre los Cecido-myiidae por la falta de setas sobre la mayoría de las papilae.Lophodiplosis trifida Gagné has been success-fully introduced into southern Florida to aid in thecontrol of paperbark, Melaleuca quinquenervia(Myrtaceae) (P. D. Pratt, unpublished). This insectwas initially described as one of 5 Lophodiplosisspecies reared from Melaleuca spp. in the vicinity ofTownsville, Qld., Australia (Gagné et al. 1997). Nofurther species has been added to Lophodiplosisand, except for L. trifida in Florida, the genus is stillknown only from eastern Australia. The other 4 spe-cies, Lophodiplosis bidentata Gagné, Lophodiplosiscornuata Gagné, Lophodiplosis indentata Gagné,and Lophodiplosis denticulata Gagné, were takenfrom separate and distinctive galls of paperbark.Lophodiplosis trifida was initially thought to be aninquiline in galls of 3 of the other species because itwas reared in association with them but not associ-ated with any particular distinctive gall of its own(Gagné et al. 1997). Subsequent observations in thevicinity of Brisbane, Qld., showed that L. trifidaforms separate, often very prominent galls (Figs. 1-4) in young shoots (Purcell et al. 2007). In the earliersituation in Townsville, stem galls of L. trifida gallswere evidently inconspicuous, perhaps containingonly 1 or 2 larvae, and had presumably beenmasked by galls of the other Lophodiplosis speciesand associated plant tissue in rearing cages. Thelarval stage of L. trifida was not described initially,unlike those of 3 of the other species of Lophodiplo-sis (that of L. denticulata remains undescribed).Now that L. trifida has taken on biological controlimportance, we take this opportunity to describe theinstars for future identification.MATERIALS AND METHODSLarvae of known L. trifida, as determined fromadults and pupae reared in quarantine in Ft. Lau-derdale, FL, were removed from paperbark shootgalls in various stages of growth. Specimens werethe progeny, many generations removed, of materialoriginally sent from Indooroopilly, Qld., Australia.Published in Florida Entomologist 92(4) December 2009594 Florida Entomologist 92(4) December 2009Figs. 1-4. Shoots of paperbark galled by Lophodiplosis trifida. 1, Galled young, soft shoot. 2, Longitudinal sectionof same largely filled with spherical larval cells containing first instars. 3, Older, woody gall with exit holes, the ar-rows indicating pupal exuviae still attached. 4, Same, longitudinal section, the topmost cell with pupa still inside.Gagné et al: Description of Lophodiplosis trifida Larva 595Specimens were placed on slides for viewing in ac-cordance with the method outlined in Gagné (1989).Other specimens were critical-point dried andplaced on SEM stubs. Terminology for larval mor-phology follows that in Gagné (1989).Description of larva of L. trifidaThird Instar (Figs. 5-12)Length, 1.3-2.0 mm (n = 10). Body cylindrical,spindleform. Head capsule hemispherical, withFigs. 5-9. Lophodiplosis trifida, third instar. 5, Entire larva (dorsolateral). 6, Anterior segments (anteroventral).7, First thoracic segment with details of spatula and papillae (ventral). 8, Posterior segments showing anus at cen-ter of terminal segment (lateroventral). 9, Detail of eighth and terminal segments (laterodorsal). Abbreviations: lp= triplets of lateral papillae; spat = spatula; spir = spiracle; tp = terminal papillae.596 Florida Entomologist 92(4) December 2009apodemes as long as capsule; antennae short, aslong as wide. Spiracles present on prothorax andon first through eighth abdominal segments. In-tegument with horizontal rows of minute spiculesventrally on anterior third of 2nd and 3rd thoracicand all abdominal segments, remainder smooth ifnot weakly and irregularly lined. Spatula (Figs. 6,11) widest posteriorly when fully sclerotized, withlong shaft, anteriorly with 2 large, triangularteeth and a shorter tooth between. Full comple-ment of papillae present except only 2 pairs onterminal segment, 1 corniform, the other seti-form. Setae present on 2 of 3 of each of the 4groups of lateral papillae and on 1 of the pairs ofterminal papillae.Second Instar (Figs. 13-14)Length, 0.6-0.9 mm (n = 10). Body shape, head,spiracles, integument and papillae as for third in-star. Spatula present, short, the acutely triangu-lar anterior tooth up to half length of shaft. Aswith third instar, full complement of papillae ispresent except for 2 pairs on terminal segmentFigs. 10-15. Lophodiplosis trifida. 10-12, Third instar: 10, entire larva (dorsal), showing position of sternal spat-ula on venter; 11, detail of anterior segments with inset showing 2× detail of lateral papillae (ventral); 12, detail ofposterior segments (dorsal). 13-14, Second instar: 13, entire larva (dorsal view), showing position of sternal spatulaon venter; 14, sternal spatula (ventral). 15, First instar, eighth and terminal segments (laterodorsal).Gagné et al: Description of Lophodiplosis trifida Larva 597and setae present on only 2 of 3 of each of the 4groups of lateral papillae and on 1 pair of termi-nal papillae.First Instar (Fig. 15)Length, 0.3-0.5 mm (n = 10). Body shape, head,and integument as for second and third instars.Spiracles present only on prothorax and eighthabdominal segment. Spatula absent. Presence ofpapillae as for second and third instars exceptthat pleural and dorsal papillae and the non-set-ose pair of terminal papillae of second and thirdinstars all with minute seta.Comments on Larval Stage of L. trifidaThe first and second instars of this species areunusual among Cecidomyiidae for the almostcomplete absence of papillar setae. Setae occur ononly 2 papillae in each of the 4 sets of lateral trip-lets and on 2 terminal papillae. The first instar, onthe other hand, has tiny setae, no longer than thediameter of their papillae, on all pleural and dor-sal papillae, in addition to the setae already men-tioned for the third and second instars. The onlyother example known of the lack of papillar setaegenerally is the genus Caryomyia, a North Amer-ican genus, in which most of species completelylack papillar setae, even those on the lateral andterminal papillae (Gagné 2008). The integumentis remarkably smooth in L. trifida, with the an-teroventral horizontal bands of spicules the onlysculpturing.DISCUSSIONThe 5 species originally placed in Lophodiplo-sis come from simple to complex galls of Mela-leuca spp. (Gagné et al. 1997). These species arean eclectic mix that, besides having a host genusin common, share the distinguishing pupal char-acter of vertexal extensions that are evidentlyused in cutting through gall tissue prior to adultemergence. Many gall midges have variouslyshaped prominences on the head for that purpose,but they are almost always extensions of the an-tennal bases, not of the vertex. Larvae of Lopho-diplosis are diverse, but this is not unusual ingenera with a variety of gall shapes (Gagné 2008).Larvae of L. trifida are unique in Lophodiplosisfor the lack of setae on most papillae, their long,narrow, tridentate spatula in the third instar, andmostly smooth integument. The other species ofLophodiplosis for which larvae are known, L. bi-dentata Gagné, L. cornuata Gagné, and L. inden-tata Gagné, have short setae on most papillae, ashort, wide, bidentate spatula, and a rugose in-tegument. The type species, L. indentata, and L.trifida both have only 4 papillae on the terminalsegment, but all 4 papillae have setae on L. inden-tata while only 2 have setae on L. trifida. Bothspecies have a spatula in the second instar. In gallmidges, a second instar spatula occurs only insome gall-making genera where it seems to havearisen de novo in each of the genera where it ap-pears (Gagné 2008).ACKNOWLEDGMENTSWe thank P. Malikul for making the slide prepara-tions, Scott D. Whittaker, SEM Laboratory Manager,Smithsonian Institution for assistance with the scan-ning electron microscope, Diana Marquez for electroni-cally arranging the photos and drawings onto plates,and James A. Lollis and Elizabeth D. Mattison for assis-tance in collecting galls and larvae, and the South Flor-ida Water Management District for financial support tothis project. We are grateful also to Keith M. Harris,Woking, Surrey, United Kingdom, David A. Nickle andAllen L. Norrbom, Systematic Entomology Laboratory,and 2 anonymous reviewers for critical comments onthe manuscript.REFERENCES CITEDGAGNÉ, R. J. 1989. The Plant-Feeding Gall Midges ofNorth America. Cornell University Press, Ithaca,New York. xiii & 355 pp. and 4 pls.GAGNÉ, R. J. 2008. The gall midges (Diptera: Cecidomyi-idae) of hickories (Juglandaceae: Carya). Mem.American Entomol. Soc. 48: 1-147.GAGNÉ, R. J., BALCIUNAS, J. K., AND BURROWS, D. W.1997. Six new species of gall midges (Diptera: Cecid-omyiidae) from Melaleuca (Myrtaceae) in Australia.Proc. Entomol. Soc. Washington 99: 312-334.PURCELL, M. F., WINEWRITER (SIC! FOR WINERITER),AND S. A., BROWN, B. T. 2007. Lophodiplosis trifidaGagné (Diptera: Cecidomyiidae), a stem-gallingmidge with potential as a biological control agent ofMelaleuca quinquenervia (Myrtaceae). AustralianEntomol. 34: 123-125.

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Description of the Larva of \u3ci\u3eLophodiplosis trifida\u3c/i\u3e, an Australian Gall Midge (Diptera: Cecidomyiidae) and Biocontrol Agent of Paperbark in Florida, USA

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