HOW TO KNOW THE IMMATURE INSECTS 



3b. Head without strong thorns, or if at base of each antenna with a 

 protuberance, thus not sharp; pupae not living in galls, but usual- 

 ly free and not enclosed in larval skin, if enclosed the larval moult 

 does not resemble a muscoid puparium 4 



4a. Thoracic respiratory organs sessil; abdomen without strong thorns 

 or leaf like elevations; legs straight 5 



4b. Thoracic respiratory organs stalked, or if sessile the abdomen 

 with strong thorns or leaf-like elevations, or the legs are recurved 

 against base of abdomen and apex of thorax, or the coxae do not 

 conceal the stemopleura and the scape of the antennae is almost 

 globose; legs straight or recurved 8 



5a. Legs short, apices of hind tarsi projecting slightly beyond apices 

 of wings; antennae short, curved across middle of eye. 

 Fig. 560 Family BIBIONIDAE 



Pupation takes place in on earthen cell in the 

 ground. 



This family, numbering some 500 species, contains 

 a few members which are sometimes exceedingly 

 nimierous. The species pict\ired is our most com- 

 mon one. All of the members of the family seem to 

 be vegetable feeders. 



Fig. 560. Bibio 

 olbipennit Say. 



5b. Legs elongate, usually all tarsi projecting for a considerable dis- 

 tance beyond apices of wings; antennae elongate, extending to or 

 beyond base of wings 6 



201 



