8 



BULLETIN 67, UNITED STATES NATIONAL MUSEUM. 



Fig. 8.— A stonefly, Pteronarcys regalis. 

 (From Comstock.) 



Trichoptera, and Mecaptera, they form the " neuropteroid " insects. 

 There are three suborders, as follows: 



Plecoptera. — The stoneflies (family Perlida?) are soft insects with 

 a rather slender, flattened body and large, many-veined wings (fig. 



8). The antenna? are long and 

 many-jointed, and in most cases 

 there are two many-jointed 

 caudal setae. A part of the 

 hind wings in the larger forms 

 folds up like a fan. The adults 

 take no food. The larva? and 

 the nymphs are aquatic, often 

 found under stones in streams. 

 The flies should be pinned and 

 the wings spread; when possi- 

 ble, however, it is well to pre- 

 serve some in alcohol. 



Anisoptera. — This suborder 

 includes one family, the 

 Ephemeridse or mayflies (fig. 163 b, c), so called, since the adult fly lives 

 but a brief period, longer, however, than one day. They are very 

 fragile creatures, with very short antennae and long, tapering bodies 

 ending in two or three slender setae, and have triangular, many- 

 veined wings. The legs are slender and very weak. They have in- 

 complete mouth-parts 

 and take no food. 

 Many species are 

 attracted to electric 

 light s in e n o r m ous 

 numbers. A remark- 

 able peculiarity is that 

 after they have issued 

 from the water and 

 have wings, they molt 

 again. This immature 

 winged condition is 

 called the " subimago," 

 and may be distin- 

 guished from the adult by the fact that the margins of the wings 

 are minutely ciliate. The larval and nymphal stages are passed 

 in the water, many feeding on vegetation, but some are predaceous. 

 They have leaf-like appendages or gills for breathing. They are 

 a favorite bait with trout fishermen, and are the models for 

 many of the artificial flies. Most should be pinned, but some speci- 

 mens saved in alcohol. 



fig. 9.— a dragonfly, plathemis lydia. 

 (From Packard.) 



