598 AN INTRODUCTION TO ENTOMOLOGY 



There are also included in this group of families those families 

 in which the fixed hairs or aculeae are retained over the general 

 surface of the wings, even though in some cases, as in the Nepticulidce, 

 the venation of the wings may be greatly reduced. The presence of 

 aculeas distributed over the general surface of the wings is believed 

 to indicate a generalized condition, as it is found elsewhere in the 

 Lepidoptera only in the Jugatae. As this condition is also found in 

 the Trichoptera, it was probably inherited from the stem foim from 

 which the Lepidoptera and the Trichoptera were evolved. In the 

 more specialized Lepidoptera the aculeas are confined to small areas 

 of the wing surface or have been lost. 



Family INCURVARIID^ 



This family and the following one differ from all other Frenatse 

 and agree with the Jugatae in having retained aculeae distributed over 

 the general surface of the wing (Fig. 710). In this family the venation 

 of the wings is but little reduced; the antennae are without an eye- 

 cap ; and the females, so far as is known, are furnished with a piercing 

 ovipositor. The moths are small or of moderate size. Many of the 

 larvae are miners when young, and later are case bearers. 



The family Incurv^ariidae includes three subfamilies, which are 

 not very distinct but which, however, are treated as families by some 

 writers. 



Subfamily Adeline.' — These tiny moths are characterized by 

 the unusually long and fine antennte of the males, which may be 

 twice or more than twice as long as the wings. Some of the species 

 are also conspicuous on account of their striking colors and markings. 



The larvas are elongate, cylindrical, with thoracic legs and five 

 pairs of prolegs. They are at first miners; later they live in portable 

 cases. They feed on the leaves of various herbs and shrubs ; but none 

 of our species is known to be of economic importance. Nearly all of 

 our species belong to the genus Adela. 



Subfamily Incurvariin^. — An interesting representative of this 

 division of the family Incurvariidae is the following well-known species. 



The maple-leaf cutter, Paracleniensia acerifoliella. — The larva in- 

 fests the leaves of maple, and occasionally is so abundant that it does 

 serious injury. The larva is at first a leaf-miner, like other adelids; 

 but later it is a case-bearer. 



The leaves of an infested tree present a strange appearance (Fig. 

 724). They are perforated with ntmierous elliptical holes, and 

 marked by many, more or less perfect, ring-like patches in which the 

 green substance of the leaf has been destro}-ed but each of which 

 incloses an uninjured spot. These injuries are produced as follows: 

 The larva, after living for a time as a leaf -miner, cuts an oval piece 

 out of a leaf, places it over its back, and fastens it down with silk 

 around the edges. This serves as a house beneath which it lives. 

 As it grows, this house becomes too small for it. It then cuts out a 

 larger piece which it fastens to the outer edges of the smaller one, the 



