THE CANADIAN ENTOMOLOGIST. 229 



Chilosia Aldrichi, n. sp. (Named after Prof. J. M. Aldrich.) 



Eyes bare, arista scarcely pubescent, scutellum without bristles, legs 

 black. 



Female. — Shining black, almost bare. Front trisulcate, coarsely 

 punctate, yellow pilose. Face shining on middle portion, powdered on 

 the sides, between the lateral sutures and the eyes short pilose, below the 

 antennae deeply concave, below the tubercle slightly so. Tubercle round, 

 projecting as far as the apex of the third antennal joint. Cheeks shining 

 black, white pilose. Occiput shining olivaceous, light pilose. Ocellar 

 area with a few black hairs. Antennal joints one and two black, third 

 flattened, oval, slightly longer than broad, reddish-brown, darker above. 

 Arista basal, almost bare, black, somewhat incrassate at base. Dorsum 

 shining black, lightly punctate, very sparsely short yellow pilose, humeri 

 dark. Pleura shining, pilose like the dorsum. Scutellum black, shining, 

 more strongly punctate than the dorsum. Abdomen oval, widest at the 

 apex of the second segment, everywhere shining black ; black pubescent 

 in the middle, and short white pilose at the sides anteriorly. Legs black ; 

 front pairs, including the coxfe on the under side and posterior tarsi at 

 apex, very indistinctly golden pubescent. Wings subhyaline, indistinctly 

 tinged on the basal half with brownish, long, rather slender, veins brown. 

 Apical cross-vein without stump, except at the base. Teguk« while. 

 Length, 9 mm. AI., 8 mm. 



Three specimens ; Craig's Mt., Idaho ; Prof. J. M. Aldrich. 



The colour of the third antennal joint in this species varies from 

 very dark reddish to almost black. 



TABLE OF NORTH AMERICAN SPECIES OF CHILOSIA. 



1. Eyes pilose 2 



Eyes bare 8 



2. Legs black Aldrichi, n. sp. 



At least the tibite more or less light-coloured 3 



3. Third joint of the antenna' light reddish-yellow or yellow 4 



Third joint of the antennae black or reddish-brown 5 



4. Abdomen shining (female), arista black 25 



Abdomen largely opaque (female), arista brown 28 



5. Third antennal joint nearly square 6 



Third antennal joint rounded 7 



6. Face in profile almost vertical below the antenna'i, produced consid- 



erably below the eyes lasiopthalvia. 



