41 



forms of aquatic insects in their immature stages. 



are printed in italics. 



are not remarkably different from the adults. The wings develop externally 



Gills 



many, minute, around 

 bases of the legs 



7 pairs on hack 



3 leaflike caudal gill- 

 plates 



internal gill chamber 

 at end of body 



wanting 



Other Peculiarities 



immense grasping lower 

 lip 



immense grasping lower 

 lip 



jointed beak for punc- 

 turing and sucking 



Habitat 



rapids 



all waters 



slow and stagnant 



waters 

 slow and stagnant 



waters 

 all waters 



Pood-habits 



mainly carnivorous 



mainly herbivorous 

 carnivorous 



carnivorous 



carnivorous 



of the same species, being more or less wormlike, having wings developed 

 mentary, or even wanting {larvae proper). 



Rear End of Body 



a pair of fleshy pro 

 legs with numerous 

 claws on them 



do., with paired larger 



hooks at tip 

 a long tapering tail 



paired hooked claws 



variable 



see next table 



Other Peculiarities 



mostly living in port- 

 able cases 



head small, often ap- 

 parently wanting 



slow or stagnant waters carnivorous 

 all waters see next table 



guished from aquatic larvae of other groups by the absence of true legs. 



Fleshy Legs, or Pro 



LEGS 



variable 



wanting 



wanting 



one beneath the mouth 



/ in front, 2 at rear 



end of body 

 wanting 

 wanting 



stout paired beneath 



j wanting 



usually wanting 



Other Peculiarities 



Habitat 



flat lobed body with 

 row of ventral suckers 



swollen thoracic seg 

 ments 



"fans" on head for 

 food-gathering 



live mostly in soft 

 tubes 



depressed form 



tubercle covered spin- 

 dle-shaped body 



shoals 



rocks in falls 



pools (at surface) 



rocks in rapids 



all waters 



still water (at surface) 

 beds in pools 



rapids under stones 



shallow pools 



Food Habits 



herbivorous mostly 



diatoms, etc. 



herbivorous 



herbivorous 



herbivorous 



herbivorous 

 carnivorous 



carnivorous 



