256 MANUAL OF NATURAL HISTORY. 



1 5. Family. — Mottled - winged Flies (Anthracidae). 



Antennae short, wide apart, ending in a pear- 

 shaped joint, very slender at tip ; proboscis 

 short ; head nearly spherical ; thorax slightly 

 elevated ; abdomen somewhat square, often 

 hairy ; wings variously mottled and spotted ; 

 legs long, slender. Fly in sunshine with 

 great agility. 



16. Family. — Vesicular -Flics (Aeroceridae). An- 



tennae minute, inserted close together ; head 

 minute, nearly all eye ; thorax elevated ; 

 body round, inflated ; wings deflexed, wing- 

 lets very large, covering balancers, wings 

 with the veins often indistinct. Slow-mov- 

 ing ; found upon plants and among flowers. 



17. Family. — Hornet -Flies (Asilidae). Antennae 



with third joint clavate, ending in a 2-jointed 

 seta ; head transverse, depressed ; eyes late- 

 ral ; lower part of face bearded ; proboscis 

 moderate, porrect in front ; thorax narrowed 

 in front ; body long, clothed with bristles ; 

 wings incumbent. Predacious ; active in 

 sunshine; make a humming noise. 



18. Family. — Large-eyed Flies (Hybotidae). Pro- 



boscis short, horizontal ; head small, globu- 

 lar ; eyes occupying nearly its entire surface ; 

 clypeus slightly hirsute ; thorax greatly ele- 

 vated ; abdomen narrow ; wings with a dis- 

 coidal post-medial cell ; thighs of hind legs 

 often thickened. Active ; prey on other in- 

 sects. 



