32 SYNOPTIC KEY 



27(28) Mouth parts arising from the hind parts of the lower 

 surface of the head and consisting of bristle-Hke organs 

 inclosed in a jointed sheath. (Comstock, 121; Lutz, 

 80.) Order Hemiptera (Homoptera) 



28(27) Mouth parts in normal position; mandibles not bristle- 

 like. 29 



.29(43) Wings net veined with very numerous veins and cross- 

 veins. 30 



30(38) Tarsi consisting of less than five segments. 31 



31(34) Antennae inconspicuous, awl shaped and slender. 32 



32(33) First and second pairs of wings nearly the same length; 

 tarsi three jointed. (Comstock, 89; Lutz, 42.) 



Order Odonata 



33(32) Second pair of wings either small or wanting; tarsi 

 four jointed. (Lutz, 40; Comstock, 86.) 



Order Plectoptera or Ephemerida 



34(31) Antennae usually conspicuous bristle-like, threadlike, 

 slightly or strongly club shaped or feather-like. 35 



35(38) Tarsi two or three jointed. 36 



36(37) Second pair of wings smaller. (Comstock, 98; Lutz, 

 76.) Order Corrodentia 



37(36) Second pair of wings broader or at least of the same 

 size as the first pair. (Comstock, 93; Lutz, 50.) 



Order Plecoptera 



38(30) Tarsi consisting of five segments. 39 



39(40) Abdomen with setiform, many-jointed anal filaments. 

 (Lutz, 40; Comstock, 86.) 



Order Plectoptera or Ephemerida in part 



40(39) Abdomen without many-jointed anal filaments. 41 



