1913] Agromyza and Cerodontha. 311 



glossy black, median vertical suture narrowly pale yellow; scutellum 

 sub-opaque, brownish-black; apical pair of scutellar bristles strongest. 

 Abdomen rather narrow; shining black-brown; hypopgium normal in 

 size. Legs black-brown, knees distinctly yello\y; tarsi yellowish 

 brown, no distinct bristles on posterior surface of mid tibia. Wings 

 narrow, clear, veins on basal half pale yellow; costa brown, first division 

 about half as long as second; inner cross vein at distinctly anterior 

 to end of first vein and middle of discal cell; outer cross vein at dis- 

 tinctly more than its own length from inner and very slightly before 

 middle of wing; veins 3-4 on last sections almost parallel; last section 

 of fifth vein about one-fourth longer than penultimate section. Hal- 

 teres yellow, knob whitish. 



Length slightly over 1 mm. 



Type: Cat. No. 15575, U. S. N. M. 



Locality: Fort Collins, Colorado, reared from mine in 

 Agropyron, July 28, 1910, (C. N. Ainslie). Webster's No. 

 6611. 



36. Agromyza dubitata, new species. 



'Female: Frons black, center stripe opaque, orbits shining at 

 base of bristles; breadth of frons a httle over one-third the width of 

 head, of each orbit about one-half the width of center stripe; four 

 rather weak orbital bristles present, situated on near to inner margin 

 of orbit; the orbital hairs less numerous than in calif orniensis; ocellar 

 region shining black, raised, the ocelli in an equilateral triangle; an- 

 tennse black, rather smaller than in preceding species, the third joint 

 not so regularly rounded at apex on upper surface; arista similar to 

 calif orniensis, but slightly shorter; face brown-black, opaque, concave 

 in profile; cheeks brown, almost as in preceding species; proboscis 

 yellow; palpi spatulate, with several moderately strong end bristles; 

 occiput narrow on upper half. Mesonotum shining black, bristled as in 

 preceding species, but the pair of bristles between posterior pair of 

 dorso-centrals shorter and more widely placed; pleurae, squamae, post- 

 no tum and scutellum as calif orniensis. Abdomen shining black; ovate; 

 last segment with the hind marginal bristles moderately strong. Legs 

 almost entirely black, the knees brownish, or the tibias and tarsi brown. 

 Halteres yellow, knob paler. 

 Length 3-4 mm. 



Type: Cat. No. 15576, U. S. N. M. 



Locality: Beverly, Massachusetts, July 19, 1869, (Bur- 

 gess). Other localities: Cottage Beaulieu, Ottawa, and He 

 de Montreal, Ottawa, Canada, June and July, 1906. Nine 

 specimens. 



Food-plant unknown. 



