26 



ZOOLOGY DIRECTIONS 



32 (31) Abdominal segments without long lateral filaments or 

 conspicuous tufts; often Avith minute gill filaments, Cyl- 



:.giiis 



caudal 

 sataa 



tarsal 

 claws - 



Fig. 11 Fig. 12 Fig. 13 Fig. 14 



Stonefly nynrnh Dsunselfly nyn^ih Dragonfly nymph teyfly nynph 



indrical larvae, generally living in portable cases 



ORDER TRICHOPTERA (larvac) 



33 (28) No prolegs on abdomen 34 



34 (35) Labium, when extended, much longer than head; at rest 



folded upon itself like a hinge and extending backward be- 

 tween the bases of the forelegs order odonata (nymphs) 



35 (34) Labium not capable of extension beyond head 36 



36 (43) Biting mouth-parts 37 



37 (40) Two or three conspicuous caudal setae. (Some larvae 



with two projections from the posterior extremity of the ab- 

 domen have no gills on either thorax or abdomen. These 

 are Coleoptera (larvae). If gills are present along sides of 

 either thorax or abdomen go on with 38) 38 



38 (39) Three caudal setae; gills on sides of abdomen; tarsal 



claws single (see fig 14) order ephemerida (nymphs) 



39 (38) Caudal setae usually two; gills mainly under thorax. 



Tarsal claws two (see fig. 11) order plecoptera (nymphs) 



40 (37) With no caudal setae 41 



