ACROCERIILE. 71 



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

 were not clean like a moulted 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 were 

 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 larvae a fly belonging to the genus Acrocera. 

 The larvae of Astomella Lindelii, 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 GENERA. 



1. Antennae with a terminal bristle 3 



Antennae without terminal bristle or style 2 



2. Antennae short, third joint rounded, witli terminal bristly hairs. . 3 

 Antennae elongate. . 7 



3. Antennae inserted near the mouth. 4 



Antennae inserted toward the vertex 6 



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



PTERODONTIA Gray. 

 Wings without such spur; anal cell absent 5 



5. Proboscis rudimentary. . . . . . ONCODES Latreille. 



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



PHILOPOTA Wiedemann. 



6. Venation complete; eyes pilose OPSEBIUS Costa. 



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



7. Proboscis rudimentary. . .V 8 



Proboscis elongate 9 



8. Eyes bare (Mexico). APPELEIA Bellardi. 



Eyes pubescent. . . .. -. - . OCN.EA Erichson. 



9. Ocelli wanting; large flies. ... .. .' . LASIA Wiedemann. 



Ocelli present ; moderately large flies. . . EULONCHA Gerstaecker. 



