THE CANADIAN ENTOMOLOGIST 



Wings with a conspicuous infuscation along costa from apex 

 of first vein to apex of second. Food-plant unknown. 

 111. . . .^ fumicosta Malloch . 



5. Mesonotum with the disc broadly black, the yellow of the 



lateral margins not carried entirely across on posterior 



margin 6 



Mesonotum with a large black or reddish mark on disc, the 

 yellow of lateral margins connected along posterior 

 margin, and usually a large subtriangular or subquadrate 

 yellow mark on middle of posterior portion of disc 10 



6. Mesonotum with disc bare except for the dorso-central 



bristles 7 



Mesonotum with numerous short setulose hairs on disc in 

 addition to the dorso-central bristles 8 



7. Mesonotum with 2 pairs of dorso-central bristles; cheek 



nearly as high as c\"e; last section of fifth vein twice as 

 long as penultimate section. Food-plant unknown. 



Idaho lima M el ander . 



Mesonotum with 4 pairs of dorso-central bristles; cheek 

 about one-third as high as eye; last section of fifth \ein 

 four times as long as penultimate section. Food-plant 

 unknown. Arizona discalis Malloch. 



8. Orbits glossy black; antennae very small; pleurcc and abdo- 



men ahnost entirely glossy black. Food-plant un- 

 known. Ill deceptiva, sp. n. 



Orbits yellow; antennae of moderate size; pleune and abdo- 

 men largely yellow 9 



9 Small species, .75-1.5 mm. in length; last section of fifth 

 vein 23/^-3 times as long as penultimate section. Lar\Te 

 in serpentine mines in leaves of \arious legumes, cab- 

 bage, cotton, nasturtium, etc. U. S.; Canada; 

 Europe pusilla Meigen . 



Larger species, 2-2.5 mm. in length; last section of fifth vein 

 13^-2 times as long as penultimate section. Food-plant 



unknown. 'Cab; Arizona; Europe scutellata Fallen. 



10. Third antennal joint largely blackened; palpi blackened at 

 apices. Food-plant unknown. Maine; 

 111 variata Malloch . 



