20 THE CANADIAN ENTOMOLOGIST. 



TWO NEW CANADIAN DIPTERA. 



BY !. M. ALDRICH, ASST. IX CEREAL AM) FORAGE INSECT INVESTIGA- 

 TIONS, U. S. BUREAU OF ENTOMOLOGY.* 



Exorista caesar, n. sp. 



A black and silvery species with black palpi; runs to couplet 5 

 in Coquillett's Re\'ision, p. 93, but does not have the characters of 

 either alternative of the couplet. 



Male — Width of front at narrowest compared with entire 

 width of head gi\'es for 8 males the decimals .263; .308; .233; .271; 

 .263; .254; .268; .300 — average, .270. These are micrometer 

 measurements. Ocellars normal, proclinate; frontals 10, rather 

 slender, reaching to the level of the arista; the uppermost stouter 

 and rather far before the \ertical; frontal stripe blackish, satiny, 

 wider than either parafacial, the latter subshining above, with 

 erect fine hairs which extend down below the anterior frontals a 

 little; these hairs are most striking above, across the ocellar region; 

 antennit black, third joint four times as long as the second, ex- 

 tending almost to oral margin ; arista thickened about 2-5 its length ; 

 parafacials narrow, silvery, bare; \ibrissae at oral margin, above 

 them a short dense row of small bristles extending hardly 3^4 of 

 the way to insertion of antennae (less in female) ; bucca about 1-6 

 the eye-height; palpi black; eyes densely hairy; proboscis short 

 and retracted. 



Mesonotum lightly cinereous between the rows of bristles, 

 which are on shining intervals; sides from humeri back more 

 silvery pollinose; dorsocentrals 4 behind, 3 before the suture; 

 inner dc 3 and 3; scutellum with 3 marginal pairs and a small, 

 nearly horizontal apical pair, also numerous long, erect hairs; 

 sternopleurals 3; pleurix? cinereous pollinose; calypters pure white. 



Abdomen shining black, anterior half of each segment silvery 

 pollinose, which is not sharply limited and leaves an indefinite 

 median black stripe; first segment with a pair of strong median 

 marginals; second with one or more pairs of discals, a pair of 

 median marginals and a pair of laterals; third segment with one 

 or more pairs of discals, and a marginal row of 10; hairs of abdomen 

 long and erect, more so toward tip. 



^Published by permission of the Chief of the Bureau. 



January, 1916. 



