i 9 6 THE STUDY OF INSECTS 



collection of pollen. After collecting a large load of pollen, often thrice as 

 large as the head (Fig. 336), the female moth places her eggs, by means 

 of her long, extensile ovipositor, into an ovary, usually of another flower 

 than that from which the pollen was collected. After oviposition, the 

 moth runs up to the tip of the pistil and thrusts the pollen into the 

 stigmatic opening. Thus is insured the development of seeds, upon which 

 the larvae hatched from the eggs placed in the ovary are to feed. As 

 many more seeds are developed than are needed by the larvae, the per- 

 petuation of the yuccas is assured. 



The full-grown larva leaves the yucca pod and makes its way to the 

 ground, where it spins a dense cocoon several inches below the surface. 

 The adult moth has a wing-expanse of about 1 inch. The wings are silvery- 

 white above. 



Family Cossid^e 



The Carp enter -moths 



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

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

 in this respect. The larvae are borers; many of them live in the solid 

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

 prolegs 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. 



The carpenter-moths 

 are of medium or large size. 

 The antennae of the males 

 are mostly bipectinate ; 

 those of the females are 

 either very slightly bipect- 

 inate or ciliate. In a few 

 species the antennae are 

 lamellate. The ocelli are 

 wanting, and the maxillae 

 are vestigial. See Figure 

 334 for type of venation. 

 The locust-tree car- 



Fig 337. — Prtonoxvstus rohmur, female. , . „ 



penter-moth , Frionoxystus 

 roblnice. — Figure 337 represents the female, natural size. The male is 

 but little more than half as large as the female. It is much darker than 

 the female, from which it differs also in having a large yellow spot, which 

 nearly covers the outer half of the hind wings. The moths fly in June 

 and July; the larvae bore in the trunks of locust, oak, poplar, willow, 



