40'6 Report of the Department of Entomology of the 



together on a single leaf, and as one leaf is consumed a fresh one is 

 involved in the web, to be destroyed in like manner. By these 

 operations there was soon formed a nest which, on being dissected, 

 was found to be composed of the remnants of several leaves tightly 

 woven together by silken threads. Interspersed in the cluster were 

 the caterpillars themselves together with their molted skins and 

 excremental particles. The nests were subsequently abandoned and 

 the caterpillars marched " en masse " to higher leaf clusters or to 

 the top of a terminal shoot, spinning webs as they advanced. As 

 they approached maturity during the latter part of June the cater- 

 pillars were more active and ravenous. Whole leaf clusters were 

 covered with webs and then completely devoured with the exception 

 of the midribs, larger veins and stems. The injuries to the seedlings 

 varied somewhat in extent but colonies of caterpillars from one 

 dozen to two dozen in number usually completely defoliated a plant, 

 while in the axils of the shoots and stretching from the tips of each 

 shoot to the central stalks of the seedlings were the tenuous webs 

 of the insects. Plates XLV and XL VI. The tents were at first whitish 

 and compact, but on exposure to the weather and from stains due 

 to moisture acting on the excrement and fragments of leaves they 

 became discolored and ragged. On pupating, towards the latter 

 part of June, the caterpillars spun their cocoons in the webbing in 

 the tops of the seedlings; and in this operation, as in feeding, the 

 social instinct was strongly manifested. As if by a given signal the 

 larger number of them ceased feeding and, abandoning the foliage 

 and taking positions in the web that were parallel to and apparently 

 of equal distance from their neighbors, they spun their cocoons side 

 by side, forming a cluster as illustrated in Plate XLI. 



breeding records. 



Some caterpillars of padellus were observed feeding on cherry 

 seedlings on June 23, 1909, and judging from their sizes and markings, 

 all of them were at this time apparently mature. On June 28 some 

 of the larvae commenced to pupate, and on July 9 the first moths 

 made their appearance. At this latter date a few caterpillars had 

 not yet spun up. The moths lived in the breeding cages through 

 July and one specimen survived until August 18. 



In 1910 mature caterpillars of malmellus were found on apple 

 seedlings on June 21. Five days later they commenced to spin 

 cocoons and nearly all of them were in the pupal state by the first 

 week in July. A few moths appeared July 6 but the adults were 

 out in their largest numbers about July 14. Although the majority 

 of them had transformed a few larvae were still unchanged at this 

 latter date. Egg deposition was first observed on July 18, when 

 practically all of the moths had emerged. One moth lived until 

 August 10. 



