GEOMYZIB^E OSCINIDJE. 105 



This group, as here defined, includes the Geomyzidee and 

 Opomyzidse and a part of the Heteroneuridse of Loew. The 

 insects included in it are always small, and sometimes minute. 

 The larvae of those few species of which the habits are known, 

 live in the stems of various plants. The flies are almost al- 

 ways caught with the beating net. 



TABLE OF GENERA. 



1. Oral vibrissae present. . . . . . . . . 2 



Oral vibrissae wanting or indistinctly differentiated from hairs. . 7 



2. Wings with bristles along the costa; bristles of antennae plumose; sec- 



ond basal cell confluent with the discal cell. 



CURTONOTTJM* Macquart. 

 Flies not having the above characters. ...... 3 



0. Costal vein continuous about the wings; wings with markings; posterior 



cross-.vein very oblique; arista pubescent. HETEROCHROA Schiner. 



Flies not having the above characters. ...... 4 



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

 Mesonotum bristly in the middle on the front; arista pectinate on the 



upper side. . . . . . . . BALIOPTERA Loew. 



5. Under side of the front femora with bristle-like spines or strong bristles; 



arista pubescent. ....'.. . ... 6 



Front femora without such bristles; front with one proclinate and one 

 divaricate bristle on each side. . , ' . DIASTATA Meigcn. 



6. Second longitudinal vein flexuous. . . . ISCHNOMYIA Loew. 

 Second longitudinal vein not flexuous. . . ANTHOMYZA Fallen. 



7. Occiput flattened; wings spotted. .... OPOMYZA Fallen. 

 Occiput convex; wings not spotted. . SCYPHELLA R. Desvoidy. 



36. 



Small, bare species. Head hemispherical, face usually ver- 

 tical in profile ; oral border usually withoiit vibrissse ; front 

 broad, flat, sometimes with bristles at the vertex. Antennae 

 usually short; third joint usually rounded. Abdomen ovate 

 or elliptical; genitalia hidden. Wings moderately or very 



* This genus belongs more properly with the Drosophilidae. 



