CHAPTER XXVIII 

 THE TRICHOPTERA 



The Caddice (sometimes spelled Caddis) Flies, as the members of this 

 order are usually called, are rather soft-bodied insects ranging in size 

 from less than an eighth of an inch to an inch or more in length. 



The wings, though much reduced in a few cases, are almost always 

 largo and well developed, with numerous longitudinal, but few cross- veins. 

 They are membranous, the front pair somewhat leathery, and all are 

 more or less densely covered with hairs which in some species are rather 

 scale-like in foi'm. The hind wings are usually broader than the front 

 pair and when not in use are sometimes folded lengthwise. The position 

 of all the wings when at rest is with their hinder margins together over the 

 back of the insect and. their costas down at the sides of the body, upper 

 faces sloping downward and outward like a house roof (Fig. 224). 



The mouth parts of the adult are poorly developed though evidently 

 modified from the chewing type and it is probable that little if any food is 

 taken in this stage. The antennae are generally well developed, and in 

 some species they may be several times' as long as the body. The legs 

 are quite long and slender. 



The larvae (Fig, 225) somewhat resemble small caterpillars in form. 

 They are nearly all found in water, chiefly that of ponds or slow-running 

 streams, though a few inhabit rapid currents. The abdomen is soft, the 

 chitinous skin being delicate, and the larvae therefore construct cases of 

 various materials -as a protection for this portion of the body. 



The Trichoptera may be defined as: 



Insects which as adults have rather soft bodies: four memhranous wings 

 with numerous longitudinal and few cross-veins, and more or less closely 

 covered by hairs, folded over the body like a house roof when at rest: mouth 

 parts rather rudimentary: antennce and legs quite long, the former so7netimes 

 exceptionally so. Larvce living in cases, nearly always in the water. Meta- 

 morphosis complete. 



The adult Caddice-fi}^, though having well-developed wings, is not a 

 strong flier and these insects are therefore most frequently found near 

 water. 



The eggs are, at least usually, laid in clusters in a mass of jelly, and 

 are probably dropped into the water. On hatching, the larvae begin the 

 construction of cases in which to live. The materials of which these are 



226 



