CLASSIFICATION 15 



minating in a distinct knob or club. Frenulum usually present. Chiefly 

 nocturnal in habit. Example, Callosamia (Fig. 237). 



Suborder Rhopalocera. Antennae simple, terminating in a dis- 

 tinct club and without conspicuous lateral processes. Frenulum absent. 

 Diurnal normally. Examples, Papilio (Fig. 27), Anosia (Fig. 244, A). 



14. Coleoptera. Metamorphosis indirect. Mouth parts mandibu- 

 late. Pro thorax large, as a rule. Wings four; front pair horny (elytra), 

 meeting in a straight line; hind pair membranous, often folded. Larvae 

 thysanuriform or cruciform. Example, Hydro philus (Fig. 28). About 

 one hundred and fifty thousand species. 



15. Diptera. Metamorphosis indirect. Mouth parts typically suc- 

 torial, but modified for piercing, lapping, rasping, etc. Prothorax small. 



B 



FIG. 27. Papilio troilus. A, Larva; B, larva suspended for pupation; C, chrysalis. Nat- 

 ural size. 



One pair of wings (mesothoracic) , membranous, transparent, with few 

 veins; wings rudimentary or absent, however, in most of the parasitic 

 species; hind wings represented by a pair of knobbed threads, or balan- 

 cers. Larvae cruciform, with the head frequently reduced to a mere 

 vestige with or without a pair of mandibles, and usually without true 

 legs, though pseudopods may be present. Example, Tipula (Fig. 29). 

 About forty thousand described species. 



16. Siphonaptera (Aphaniptera) . Metamorphosis indirect. Head 

 small. Eyes simple or absent. Mouth parts suctorial. Body laterally 

 compressed. Thoracic segments subequal. Wings absent or at most 

 quite rudimentary. Larvae with a head, mandibulate, apodous. Para- 



