496 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. 



ran reach from the lower end of its case, the latter being sewed to 

 the leaf surface (Z>, a). After each meal the caterpillar detaches 

 its case and moves off to another place. The cigar case-bearer thus 

 makes many small mines (Z>, 6), but its mining habit is only inci- 

 dental to its feeding. It derives its protection from its cases, which 

 it wears throughout its larval life, finally using the second as a re- 

 treat during its chrysalis stage. The pistol case-bearer renounces 

 mining altogether, making its case of silk, and enlarging it as it 

 grows. In feeding it makes irregular holes clear through the 

 leaf or eats their tissue down to the larger veins and the mid rib 

 after the manner of common leaf- feeding caterpillars. These spe- 

 cies of minute moths and several others that frequent the orchard 

 are thus noted for the great variety of skill they possess in their 



Fig. 7. — Apple twigs in fall showing Bucculatrix cocoons along lower sides, and scarred 

 leaves on which the caterpillars have fed. 



caterpillar stages as miners or as case makers. But one of them is 



famous as a cocoon builder. This is Bucculatrix poniifoliella, or 



THE RIBBED-COCOON-MAKER OF THE APPLE. 



As with the resplendent shield-bearer, autumn is the time when one 

 is most likely to make first acquaintance, with Bucculatrix in the 

 orchards. A search at this season along the under sides of the twigs 

 and branches of the apple trees is pretty likely to reveal little, whit- 

 ish, spindle-shaped objects, about a third of an inch in length, stuck 

 lengthwise against the bark. (Fig. 7, and pi. 2, ^L) A closer in- 

 spection (fig. 8) shows that each is fluted with a number of ridges 

 that disappear at the tapering ends; which character identifies them 

 as the cocoons of the Bucculatrix caterpillar. Ordinarily they are 

 scattered along here and there, but, when the caterpillars have been 



