202 NEW YORK STATE MUSEUM 



Rhizomyia Kieff. 



1897 Kieffer, J. J. Syn. Cecid. Eur. & Alg., p. 56-57 



1899 Riibsaamen, E. H. Biolog. Centralbl., 19:534 (Coccomorpha) 



1904 Kieffer, J. J. Soc. Sci. Brux. Ann., v. 28, pt 2 Separate, p. 7' 



1910 Riibsaamen, E. H. Zeitschr. Wissenschaftl. Insektenbiol, 6:200-02 



191 1 Felt, E. P. N. Y. Ent. Soc. Jour., 19:44 



This genus is easily distinguished from all other Dasyneuriariae 

 by the triarticulate palpi and the 12 antennal segments, those of 

 the female subsessile, while in the male the stem is nearly as long as 

 the basal enlargement. The terminal clasp segment of the male is 

 very long, slender, and the ovipositor short and lobed. The type of 

 this genus isR. perplexa Kieff. 



A number of American species, closely allied to, if not cogeneric 

 with, the European forms, have been tentatively referred to this 

 genus. It is possible that further studies will warrant the placing 

 of our American species in a separate genus. Two of the European 

 species have been reared from the leaf sheath and roots of sedge, 

 while our American species were obtained from jars containing 

 various characteristic galls. The conditions were such as to lead 

 us to suspect that the rearings were accidental. 



The peculiar larva of R. circumspinosa Rubs, is oval, 

 flattened and resembles a Coccid, hence its generic designation of 

 Coccomorpha. This larva was found under the sheath of Carex 

 leaves, while that of R. perplexa Kieff. occurred upon the 

 roots of a sedge. 



Key to species 

 Males 

 a Stem of fifth antennal segment one-quarter longer than the basal en- 

 largement 

 b Abdomen light yellowish or yellowish orange ; tibiae fuscous straw, 

 tarsi dark brown or black, basal enlargement of fifth antennal 

 segment with a length twice its diameter, the ventral plate roundly 

 emarginate, the dorsal plate short, deeply and narrowly emargin- 



ate. Reared from rolled ash leaves 



fraxinifolia Felt, C. ai572a 



bb Abdomen fuscous yellowish, the segments margined posteriorly with 



dark brown, basal enlargement of fifth antennal segment with a 



length twice its diameter, the ventral plate very deeply and 



roundly emarginate c i n c t a n. sp., C. 722 



bbb Abdomen pale orange, basal enlargement of fifth antennal segment 

 with a length twice its diameter, the ventral plate broadly and 

 roundly emarginate, the dorsal plate very short, deeply and 

 roundly emarginate ungulata Felt, C. 1221 



