194 Journal New York Entomological Society, t^'o'- xxiv, 



cases hardly extending to the base of the abdomen, the wing cases to the 

 third abdominal segment, the leg cases to the fifth abominal segment ; dorsum 

 of the abdomen nearly smooth, the posterior extremity broadly rounded. 



Diarthronomyia occidentalis new species. 



Numerous small midges were reared by Mr. P. H. Timberlake in 

 September, 1912, from small, oval, thin-celled galls on the leaves of 

 Artemisia hcterophylla, collected at the Sweet Water Dam, San 

 Diego County, Cal., and also from flower buds taken in the Puente 

 Hills near Whittier. It was also reared from a similar, nearly verti- 

 cal solitary or clustered grayish or almost black oval gall on the under 

 side of leaves of Artemisia tridcntata collected at Salt Lake City, 

 Utah, in May, 1915. The species is a small one, the gall resembling 

 very closely that produced by the European chrysanthemum midge, 

 D. hypogcca H. Lw., and the adults have a close affinity with this 

 species, though they may be easily distinguished therefrom by the 

 somewhat smaller size and the smaller number of antennal segments. 



Gall. — An oval, thin-walled, pubescent cell, length about i mm., attached 

 to the under side of the leaf and at an oblique or nearly vertical angle to the 

 supporting surface. Gall grayish on A. heterophylla or grayish or nearly black 

 on A. tridentata. The galls in the flower buds are recorded by Timberlake 

 as apparently the same though rather thinner walled. 



Female. — Length 1.25 mm. Antennae extending to the base of the ab- 

 domen, sparsely haired, pale flesh-colored; 14 to 15 subsessile segments, the 

 fifth with a stem about one-fifth the length of the cylindric basal enlargement, 

 which latter has a length two and one-half times its diameter; terminal seg- 

 ment slightly reduced, narrowly rounded apically. Palpi ; first segment small, 

 globose, second smaller, subglobose. Eyes black; face yellowish. Mesonotum 

 yellowish brown. Scutellum and postscutellum pale yellowish ; abdomen pale 

 reddish, fuscous yellowish distally. Legs pale yellowish, the claws slender, 

 evenly curved, unidentate, the pulvilli a little shorter than the claws. Ovi- 

 positor about half the length of the abdomen, the terminal lobes rather long, 

 roundly tapering to a narrowly rounded apex, sparsely setose. 



Male. — Length 1.25 mm. Antennae extending to the third abdominal seg- 

 ment, sparsely haired, pale yellowish; 15 or 16 segments, the fifth with a stem 

 three-fourths the length of the cylindric basal enlargement, which latter has 

 a length two and one-fourth times its diameter; terminal segment produced, 

 with a length about three times its diameter. Palpi ; first segment short, sub- 

 quadrate, second smaller, subquadrate. Coloration similar to the female, ex- 

 cept that the abdomen is pale yellowish and the genitalia fuscous and the legs 

 paler than in the female. Genitalia ; basal clasp segment short, stout, broadly 

 triangular; terminal clasp segment short, stout, with a conspicuous tooth 

 apically ; dorsal plate moderately long, triangularly emarginate, the lobes 



