284 ELEMENTARY STUDIES IN INSECT LIFE 



B. Mouth-parts biting, four wings. 



C. Front wings leather-like, usually narrower than hind 

 wings, which are delicate, and fold in repose in the man- 

 ner of a fan. Metamorphosis incomplete. 



ORTHOPTERA. 



CC. Front and hind wings similar in texture, frequently 

 with many cross-veins forming a network. Little or no 

 fan-like action in the closing of hind wings. Metamor- 

 phosis incomplete in some forms, complete in others. 



NEUROPTERA. 



CCC. Wing-covers, i.e., .the upper pair, shell-like, meeting 



in a straight line along the back, forming cases over and 



concealing the delicate infolded membranous wings proper. 



Metamorphosis complete. COLEOPTERA. 



CCCC. The four wings membranous. Front wings larger 



than hind wings; hind wings always small, and not folding 



fan-like in repose. Mouth-parts mandibulate, but in many 



forms there is present a tubular proboscis; the mandibles 



being in the form of jaws and the maxillae and labium 



fitted for taking liquid food. HYMENOPTERA. 



BB. Mouth suctorial. Four wings. 



C. Mouth perfectly suctorial. 



D. The front pair wings leather-like, with more mem- 

 branous apex (Heteroptera see page 184), or entire 

 wing parchment-like or membranous ( Homoptera see 

 page 185.) Metamorphosis incomplete. 



HEMIPTERA. 



DD. Four large wings covered with scales. Metamor- 

 phosis complete. LEPIDOPTERA. 

 CC. Mouth imperfectly suctorial. Four very narrow 

 fringed wings. Very small insects. Metamorphosis incom- 

 plete. THYSANOPTERA. 

 BBB. Mouth suctorial, mandibulate and maxillate bristles 

 present in some forms, and used for piercing. Two wings, 

 the hind wings being represented by a pair of knobbed, 

 thread-like organs. Metamorphosis complete. 



DIPTERA. 



APTERA. 



A. Abdomen composed of ten segments; ventral tube wanting 



on its first segment. Suborder Thysanura. 



(Fish Moths.) 



