LEPIDOPTERA 



601 



like organ, which hooks into a well-developed frenulum hook (Fig. 

 726); in most cases the costal spines are well developed; this is 

 shown in the accompany- 

 ing figure; and the anal 

 lobe of the fore wing is 

 sometimes quite distinct. 

 With the exception of 

 several gall-making spe- 

 cies oi Ectcrdemia , the lar- 

 vae of all species of which 

 the life-history is known 

 are miners within the 

 tissues of leaves (rarely in 

 fruits) or in bark. They 

 show a preference for trees 

 and shrubs, but some mine 

 in the leaves of herbaceous 

 plants. The larva at first makes a very narrow linear mine. Thismine 

 may continue as a linear mine, gradually broadening throughout its 

 course, or it may at some period abruptly enlarge into a blotch . When 

 full-grown, the larva, with few exceptions, leaves the mine and, drop- 

 ping to the ground, spins a dense, flattened cocoon amongst rubbish 

 or on the loose surface soil. (Braun '17.) 



More than seventy species have been described from our fauna, 

 and doubtless many more are to be discovered. The Nepticulid^ of 

 North America was monographed by Braun ('17). 



Fig. 726. — Wings of Ohriissa ochrefasciella, male. 

 (After Braun.) 



Family COSSID^ 



The Carpenter-Moths 



This family includes moths with spindle-shaped bodies, and nar- 

 row, strong wings, some of the species resembling hawk-moths quite 

 closely in this respect. The larvse are borers; many of them live in 

 the solid wood of the trunks of trees. The wood-boring habits of the 

 larvcB suggest the popular name carpenter-moths for the insects of 

 this family. 



These moths fly by night and lay their eggs on the bark of trees, 

 or within tunnels in trees from which adult carpenter-moths have 

 emerged. The caterpillars are nearly naked, and, although furnished 

 with pro-legs as well as true legs, are grub-like in form. The pupa 

 state is passed within the burrow made by the larva. When ready 

 to change to an adult, the pupa works its way partially out from its 

 burrow. This is accomplished by means of backward-projecting saw- 

 like teeth, there being one or two rows of these on each abdominal 

 segment. After the moths have emerged, the empty pupa-skins can 

 be found projecting from the deserted burrows. 



