ACROCERIDyE. 71 



sylvestris, nearly full grown. The skin of the legs and thorax 

 were not clean like a mo\ilted skin, but dirty and opaque, as 

 though eaten out, and the skin of the abdomen when present 

 was torn and shriveled. From this I concluded that the mag- 

 gots came out of the spiders, and from their size must have 

 nearly filled them. The maggots varied considerably in size, 

 the largest being a quarter of an inch long, while others w^ere 

 not more than half as large. The hinder half of the body was 

 thicker than the front half and nearly spherical. They hung 

 head downward, holding to the web by their jaws and were 

 also partly supported by threads under and around them." 

 The author of the foregoing, J. H. Emerton, reared from other 

 specimens of these larvte a fly belonging to the genus Acrocera. 

 The larvae of Astomella LlndeHl, according to Brauer, are so 

 lodged in the abdomen of the spider that the posterior termi; 

 nal stigmata are in relation with the lung-tubes of the spider. 

 The eggs are said to be deposited on dried twigs. 



TABLE OF GEXEKA. 



/I. Antennae with a terminal bristle. ....... 3 



Antenna; witliout terminal bristle or style. ..... 2 



2. Antenna; short, third joint rounded, vvitli terminal bristly liairs. . 3 



Antennae elongate. .......... 7 



o. Antennae inserted near tlie mouth. ...... 4 



Antennae inserted toward the vertex 



4. Wings with a stout costal spur near the tip of the auxiliary vein. 



Ptekodontia Gray. 



Wings without such spur; anal cell absent. . . • . • ■ 'J 



N c^ \^ — •■' 



5. Proboscis rudimentary Oncodes Latreilie. 



Proboscis elongate, directed backwards (Central and South America). 



Philopota Wiedemann. 



(i. Venation complete; eyes pilose Opsebius Costa. 



Venation more or less obsolete; eyes bare. . . Ackocera Meigen. 



7. Proboscis rudimentary .8 



Proboscis elongate .......... 



8. Eyes bare (Mexico). Appeleia Pellardi. 



Eyes pubescent. ....... Ocn^cEa Erichson. 



9. Ocelli wanting; large flies Lasia Wiedemann. 



Ocelli present; moderately large flies. . . Eueoncha Gersta3cker. 



