152 Journal New York Entomological Society. [Vol. xvi. 



ian species of the latter genus he groups in two subgenera, based largely 

 on the structure of the scutellum and the arista, and on color. On 

 examining European specimens of Meigen's brevipennis I think it de- 

 serves generic separation from the other species, and that Bezzi is cor- 

 rect in placing it under Elachiptera Macq. 



The following table contains the known North American species, 

 together with two which are considered new. 



1. General color yellow or reddish yellow 2 



General color black 3 



2. Mesonotum with three longitudinal black lines eitnota Lw. 



Mesonotum with two lines attenuata, new species. 



Mesonotum without longitudinal lines flavida Will. 



3. Head, except sometimes the antennae, wholly black 4 



Head more or less marked with yellow 5 



4. Scutellum without small tubercles nigricornis Lw. 



Scutellum with small tubercles nigriceps Lw. 



5. Dorsum of abdomen red, with brown margins formosa Lw. 



Dorsum of abdomen black 6 



6. Mesonotum with two longitudinal lines composed of grayish yellow, microscopic 



hairs bilineata Adams. 



Mesonotum without such lines 7 



7. Shining, second costal segment incrassate 8 



Subshining, second costal segment at most but little thickened... languid Lw. 



8. Scutellum with tubercles costata Lw. 



Scutellum without tubercles .penita, new species. 



Crassiseta attenuata, new species. 



Head yellow, frontal triangle shining, nearly reaching antennae, ocellar dot 

 black ; sides of front and face with faint tinge of silver ; upper margin of antennae 

 and arista black ; latter broad but rapidly attenuated on outer third. Thorax yellow ; 

 mesonotum with two sublateral, black lines ; scutellum without tubercles. Halteres 

 yellow. Abdomen shining black. Legs yellow, infuscated on tip of tarsi ; the right 

 hind tibia is swollen and black, but this is probably pathological, or in some other 

 way abnormal. Wing with a tinge of brown. Length 3 mm. 



One specimen from San Jose de Costa Rica, collected by Prof. 

 P. Biolley. 



Crassiseta penita, new species. 



Head black ; front yellowish anteriorly, trontal triangle large, shining ; occiput 

 slightly grayish pruinose, triangle projecting downward from vertex, shining ; an- 

 tennae reddish yellow, arista black ; mouth parts tinged with yellow. Thorax shin- 

 ing black; mesonotum scrobiculate^ except laterally and on two subdorsal ridges 

 anteriorly ; scutellum scrobiculate, without tubercles ; halteres yellow. Abdomen 

 shining brownish black, anteriorly tinged with yellow. Legs reddish yellow ; tibiae 

 and tarsi fuscous, the anterior tarsi being daik brown. Second costal segment of 

 wing only slightly incrassate. Length 3 mm. 



Two specimens from Wisconsin. 



