Packard.] 



INSECTS AS ARCHITECTS. 



309 



convert them into sacks which they bear about with them, 

 much as in tlie caddis worms. The 3'oung clothes moth 

 (Fig. 243, a, its sack ; 6, chrysalis) bites off pieces of the 

 woollen cloth on which it feeds, sticks them together by 

 means of a silky secretion, and thus forms a close, dense 

 sac. As it grows, instead of throwing away the sac it has 

 outgrown, it makes a slit on each side, fills in the rent with 

 new material, and adds more to the mouth, thus enlarging 

 and refitting its house. 



Certain small caterpillars of the Acrobasis and other allied 

 genera economize their excrement, constructing between the 



Fig. 241. 



Mauy-chambered Grape Gall. 



leaves of the birches, on which they feed, little trumpet- 

 shaped cases out of the little black pellets. 



Tlie case of the "basket worm" is a curious object. Fig. 

 244 (a, moth ; &, wingless female ; c, larva ; rf, case) repre- 

 sents the different stages of growth of a small species found 

 in Florida by Mr. T. Glover. Our common basket worm is 

 a familiar object in the middle and southern states. Its 

 case is about two inches in length, and while the interior is 

 lined densely with silk, on the outside are stuck pieces of 

 cedar twigs and leaves, sometimes half an inch in length. 

 We have seen the young just after leaving the egg beginning 

 to build their cases, which are at first broad and shallow like 

 a basket ; and it is a comical sight to see the little tiny 

 worms creeping rapidly along, their tails held straight ui) in 



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