29S 



NORTH AMERICAN DIPTKRA. 



not at all sharp, and no two writers agree as to what they 

 are; indeed there seem to be none. Curtonotum is not in- 

 eluded here, but will be found among the Drosophilidae. 

 Tauromyia, which v. d. Wulp thought might belong to 

 this group, is most assuredly not a Geomyzid. 



The larvae of those few species of which the habits are 

 known, live in the stems of plants. 



TABLE OF GENERA. 



1. Oral vibrissa; distinctly differentiated. ..... 2 



Oral vibrissa? absent or indistinctly differentiated from adjacent 



hairs. ........... 8 



2. Mesonotum bristly in the middle in front 3 



Mesonotum bristly in the middle on the posterior part only. 5 



3. Arista pectinate above; one orbital bristle. . . Balioptera. 

 Arista not pectinate; two fronto-orbital bristles. ... 4 



4. Cheeks as broad as the vertical diameter of the eyes; wings un- 



marked. Zagonia. 



Cheeks narrow; wings variegated {Heterochroa {Peratochtztus) 01- 

 nata Johnson) (3,4). . . . Spilochroa Will. 



5. Under side of front femora with bristles or bristle-like spines. 6 

 Under side of front femora not with bristles or spines. Diastata. 



6. Second longitudinal vein strongly cnrved forward, flexnons (p. 80, 



14). Ischnomyia. 



Second longitudinal vein not flexuous. ..... 7 



7. Face with a nose-like carina above; no postvertical bristles; front 



with one proclinate bristle on each side (1, 2) . 



Sinophthalmus . 

 Face not carinate; tworeclinate bristleson each side (5, 6, 7). 



Anthomyza. 



8. Occiput flattened; wings spotted 9 



Occiput convex; wings not spotted (8, 0, Scyphelld) . 



Chiromyia Rezzi. 



9. Arista long plumose. Scutops. 



Arista not plumose Opomyza. 



