HEX A POD A. 8 1 



GG. Wings with branching veins and comparatively few 

 cross-veins, or veinless. 

 H. Tarsi two- or three-jointed. 



I. Posterior wings smaller than the anterior. 



p. 98 CORRODENTI A. 



II. Posterior wings as large as or larger than the 

 anterior ones. (Certain Stone-flies.) p. 93. 



PLECOPTERA. 

 HH. Tarsi four- or five-jointed. 



I. Abdomen with setiform, many-jointed anal fila- 

 ments. (Certain May-flies) p. 86. EPHEMERIDA. 



II. Abdomen without many-jointed anal filaments. 

 J. Prothorax horny. First wings larger than the 



second, naked or imperceptibly hairy. Second 

 wings without, or with few, unusually simple, 

 veins. Jaws (mandibles) well developed. Palpi 



small, p. 599 HYMENOPTERA. 



JJ. Prothorax membranous or, at the most, 

 parchment-like. Second wings as large as or 

 larger than the first, folded lengthwise, with 

 many branching veins. First wings naked or 

 thinly clothed with hair. Jaws (mandibles) in- 

 conspicuous. Palpi long. Moth-like insects. 

 p. 186 TRICHOPTERA. 



LIST OF ORDERS OF THE HEXAPODA. 



THYSANURA. HEMIPTERA. 



EPHEMERIDA. NEUROPTERA. 



OUONATA. MECOPTERA. 



PLECOPTERA. TRICHOPTERA. 



ISOPTERA. LEPIDOPTERA. 



CORRODENTIA. DlPTERA. 



MALLOPHAGA. SIPHONAPTERA. 



EUPLEXOPTERA COLEOPTERA. 



ORTHOPTERA. HYMENOPTERA. 

 PHYSOPODA. 



