Linares, B.

Poinar, G.O. jr

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Hexamermis dactylocercus sp. n. (Mermithidae : Nematoda), 
a parasite of Aeneolamia varia (Cercopidae : Hornoptera) 
in Venezuela 
George 0. POINAR, Jr and Blas LINARES 
Division of Entomology and Pamsitology, University of Califomia, 
Berkeley, Ca 94720, USA and Estacion Experimental, Araure, Acarigua, Venezuela 
SUMMARY 
Hexamermis dactylocercus n. sp. (Mermithidae) is described from the homopteran Aeneolamia varia (Cercopidae) in Venezuela. 
Rates of parasitism in this economically important pest of sugar cane reached 50 % in some fields. The characteristic digit-like 
appendage on the tails of the adults of Hexamermis dactylocercus n. sp. separates this species from previously described members 
of the genus. 
h%UMÉ 
Hexamehs dactylocercus sp. n. (Mermithidae : Nematoda), 
parasite de Aeneolamia varia (Cercopidae : Hornoptera) au Venezuela. 
Description est donnée de Hexamermis dactylocercus provenant de Aeneolamia varia (Cercopidae) originaire du Venezuela. Cet 
insecte économiquement dangereux pour la canne li sucre est parasite à des taux pouvant atteindre 50 % dans certains champs. 
L’appendice digité caractéristique situé à l’extrémité de la queue sépare cette espéce de toutes celles décrites antérieurement dans 
le genre. 
Relatively few mermithid parasites of members of the 
homopteran family Cercopidae have been reported 
(Poinar, 1975). The first such record was made by 
Kershaw (1913) when an unidentified mermithid was 
found parasitizing Tomaspis saccharina Dist. in Trini- 
dad. Subsequent findings were made by Weber (1930) 
who reported an unidentified mermithid in the Euro- 
pean spittlebug, Aphrophora salicis (Degeer) and Wea- 
ver and King (1954) who identified Agamemtis decau- 
data parasitizing Philaenus spumarius (L.) in Ohio. 
Records of mermithid parasitism in the cercopid genus 
Aeneolamia have been reported by Lloyd (1959) in 
Mexico and by Guagliumi (1962) in Venezuela. Both of 
the above authors identified the nebatode as belonging 
to the genus Hexamermis Steiner, 1924 but no descrip- 
tion was provided. 
A mermithid was discovered parasitizing nymphs of 
Aeneolamia varia in the Portuguesa state of Venezuela 
(western central region of the country). Such parasitized 
nymphs were collected from May 10 to September 1, 
1981 and from May to June, 1982. Nematodes were heat 
.killed, f=ed in formalin, and processed to glycerin. The 
rate of infection reached 32 % from May 10 to Sep- 
tember 1,198l (n = 1982) and 50 % from May 1 to June 
1, 1982 (n = 1982). Since the host is an important pest 
of sugarcane, interest was expressed in the identity of the 
parasite. The present study describes this nematode as 
Revue Nématol., 8 (2) : 109-l II (1985) 
a new species of the genus Hexamermis. It is quite likely 
that this is the species referred to by Guagliumi (1962). 
Hexamermis dactylocercus II. sp. 
Fig. 1 
MEAWFCEMENTS 
Femules (n = 8) : L = 7.14 cm (4.7-8.8); greatest 
diameter = 274 pm (192-352); distance from head to 
nerve ring = 309 prn (265-378); V = 39 (30-45); length 
of vagina = 20 1 prn (174-269); distance from end of 
trophosome to tail tip = 274 prn (202-504). 
MuZes (n = 10) : L = 4.4 cm (2.2-6.3); greatest 
diameter = 182 p.m (128-224); distance from head to 
nerve ring = 284 !&rn (233-334); spicules = 158 prn 
(114-206); tail = 204 p.m (152-240); body diameter at 
cloaca = 160 p (11 l-206). 
HoZotype (female) : L = 8.0 cm; greatest diameter 
= 392 p; distance from head to nerve ring = 346 p,rn; 
V = 42 %; length of vagina = 199 p; distance from 
end of trophosome to tail tip = 504 pm. 
Allotype (male) : L = 5.0 cm; greatest diameter 
= 192 p; distance from head to nerve ring = 290 prn; 
109 
G. 0. Poinar & B. Linares 
Fig. 1. Hexamermis dactylocercus sp. nov. 1 : dorsal view of male head; 2 : cross-section of male at mid-body; 3 : dorsal 
view of female head; 4 : lateral view of vagina; 5 : « en face » view of female; 6 : lateral view of male tail; 7 : ventral 
view of male tail; 8 : lateral view of tail of a molting female showing the two shed cuticles. 
110 Revue Nématol., 8 (2) : 109-111 (1985) 
Hexamermis dactylocercus SP. n. 
spicules = 206 um; tail = 212 prn; body diameter at 
cloaca = 190 prn. 
DESCRIPTION 
Mermithidae Braun, 1883. Hexamennis Steiner, 1924 
as characterized by Rubstov (1978). 
Adults : Medium sized nematodes with a relatively 
thick cuticle (16-38 um thick) possessing distinct cross 
fibers; body narrowing slightly in the head region, six 
hypodermal tords at mid-body, the lateral and ventral 
tords possessing two rows of nucleated cells; six head 
papillae arranged in one plane, however the head is 
slightly bilobed with each lobe bearing three cephalic 
papillae : mouth opening terminal; amphids located 
behind the lateral cephalic papillae, openings small and 
pore-like; proximal portion of vagina lined with thick 
layers of cuticle, narrowed distal portion roughly equal 
in length to the proximal portion but bent in various 
directions, giving the vagina a J, V or rarely a modified 
S-shape; vulva opening circular; vulvar lips absent. 
Spicules paired, separate, equal, pointed at tips, nearly 
straight, slightly shorter than, equal to or slightly longer 
than the body width at the cloaca; genital papillae 
arranged in six or seven broken rows, variable in number 
and location. Some females possess a vestigal anal 
opening at 189-208 i.n-n from the posterior end; tails of 
both sexes with a thick digit-like cuticular projection. 
Postparasitic juveniies : With a thick cuticle (9-12 um) 
also possessing cross fibers; tail terminus bearing a 
distinct appendage, 41 prn (37-48) long. Molts twice 
(simultaneously) after leaving host to become an adult. 
TYPE HOSTANDLOCALITY 
Aeneolamia varia Fab. (Cercopidae : Homoptera), at 
Guanare Estate Portuguesa, Venezuela. 
TYI'ESPECIMENS 
Holotype (female) and allotype (male) deposited in 
the Nematology Collection, University of Califomia, 
Accepté pour publication le 21 févner 1985. 
Davis, Califomia. Paratypes are in the author’s (GOP Jr) 
collection. 
DIAGNOSIS 
The characteristic digit-like appendage on the tails of 
the adults of H. dactylocercus n. sp. separates this species 
from previously described members of Hexamermis. 
Other mermithids described from Hemiptera include H. 
microamphidis Steiner, 1925 from Helopeltis antonii in 
Indonesia and Agarnermis unka Kaburaki & Imamura, 
1932 described from leafhoppers in Japan. H. dactyZo- 
cercus n. sp. differs from the former species by having 
longer spicules and from the latter by having a tail 
appendage on the postparasitic juveniles. It differs from 
both by the cuticular projection on the adult tails. 
REFERENCES 
GUAGLIUMI, P. (1962). Las plagas de la caria de A,&car en 
Venezuela. Vol. II., Venezuela, Minist. Agric. y Cria. Centro 
de Investigaciones Agronemicas, Maracay : 568-569. 
IQBURAKI, T. & IPAAMUIW, S. (1932). Mermithid- 
worm parasitic in leaf-hoppers, with notes on its life history 
and habits. hoc. imp. Acad. Japan, 8 : 139-141. 
KERSHAW, J. C. (1913). Trinidad Dept. Agric., Special Cire. 
No. 5, 8 p. Lloyd, D.C. (1959). Report on Aeneolamia 
investigations in Eastem Mexico, April-October, 1959. 
Mexican Govt. (unpubl. rep.). 
POINAR, Jr. G. 0. (1975). Entomogenous nenzatodes. Leiden, 
E.J. Brill, 317 p. 
RUBSTOV, 1. A. (1978). [Mermithida, Classification, importance 
and use]. Leningrad, « Nauka P>, 207 p. (In russian). 
STEINER, G. (1925). Mermithids parasitic in the tea bug 
(Helopeltis antoniisign.). Mededell. Proefst. Thee, 44 : 10-16. 
WEAVER, C. R. & King, 0. R. (1954). Meadow spittlebug. Ohio 
Agr. Exp. Sta. Bull., 741, 99 p. 
WEBER, H. (1930). Biologie der Hemipteren. Eine Naturge- 
schichte der Schnabelkerf?. Berlin, Springer Verlag, 543 p. 
Revue Nématol., 8 (2) : 109-111 (1985) 111 


Hexamermis dactylocercus sp. n. (Mermithidae : Nematoda), a parasite of Aeneolamia varia (Cercopidae : Homoptera) in Venezuela

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