CHAPTER XXII 

 THE WINGS OF THE TRICHOPTERA 



The order Trichoptera as heretofore recognized includes those insects 

 the larvffi of which are commonly known as caddice-worms and the adults 

 as caddice-fiies. This is a well-defined, homogeneous group of insects. 

 There is, however, a group of moth-like insects that have been included in 

 the order Lepidoptera which so far as the structure of their wings is con- 

 cerned and in some other respects are more closely allied to the Trichoptera 

 than they are to the Lepidoptera, this is the Micropterygina. 



To continue to include the Micropterygina in the Lepidoptera raises a 

 question of phylogeny to which I can find no answer; while the transference 

 of this family to the Trichoptera removes this difficulty. This phase of the 

 subject is discussed later, in the concluding part of this chapter. 



Although the Micropterygina are closely allied to the caddice-flies, there 

 are differences between the two groups that warrant the regarding of each 

 as a distinct suborder. I therefore propose the division of the Trichoptera 

 into two suborders, the Phryganeina or aquatic Trichoptera andtheMicrop- 

 ten^gina or terrestrial Trichoptera. 



The distinction in habits between the Phryganeina and the Microp- 

 terygina is not an absolute one. Among the Phryganeina the lan'S of the 

 genus Enoicyla live under moss at the foot of trees, chiefly in woods and 

 often at great distance from water; and, on the other hand, the known 

 lar\'as of the genus Micropteryx, as now restricted, might be considered as 

 semi-aquatic since they live in wet moss. 



SUBORDER PHRYGANEINA 



The Aquatic Trichoptera 



The suborder Phryganeina includes those Trichoptera in which the 

 wings are clothed with long silky hairs, the tracheation of the wings of the 

 pupa is reduced, and the larvae are aquatic. 



(a) THE MORE GENERAL FEATURES OF THE WINGS OF THE PHRYGANEINA 



The two pairs of wings are membranous and usually more or less densely 

 clothed with long silky hairs. The fore wings are denser than the hind wings 

 and are often slightly coriaceous ; in a few forms the wings are naked. The 

 hind wings are shorter than the fore wings; but they are usually broader; 

 this is due to an expansion of the anal area of the hind wings. In a few- 

 species the hind wings are reduced so that they are smaller than the fore 



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