Appendix. 133 



roots. Simpsont states that many are placed in cracks in the ground and 

 that a Mr. McPherson reports having found many among the clods of earth 

 in the orchard. Undoubtedly the larvae prefer to pupate under scales of 

 bark on the trunk and larger limbs or in other dry secluded places above 

 the ground — in breeding cages they almost invariably go to the top — but 

 it seems evident that under certain circumstances they may pupate on or 

 beneath the surface of the soil, and that clean smooth trees and clean 

 culture are valuable aids in the warfare against this pest. 



Having found a suitable place, whether it be on trunk or branch, in 

 barrel, box or storeroom or under a clod, the larvae hollows out a little 

 oval cavity with its jaws and proceeds to envelope itself in a thin tough 

 cocoon of silken threads intermingled with particles of the surrounding 

 substance. Figure h shows a larvae in a winter cocoon, on the under 

 surface of a piece of bark. If the cocoon is formed by a larvae of the first 

 brood, in July or early August, in two or three days it will undergo a 

 wonderful transformation — a complete change of form. It is then a pupae. 

 A larvae of the second brood remains as a larvae within its cocoon until 

 the following spring when it too transforms to a pupae. A pupae some- 

 what enlarged is shown in Figure j. Whether the change to the pupae 

 occurs in a few days as in the first brood or is delayed until spring as in 

 the second, the insect remains in the pupal stage only two or three weeks. 

 Then, by wriggling movements, aided by the spines on the back of each 

 segment, the pupae v/orks its way out of its cocoon and is born again. 

 It is then a most beautiful object — the moth. In breeding cages, moths 

 of the first brood emerged August 3, from cocoons that were spun July 19, 

 and in which the larvae pupated July 21. Moths of the second brood, which 

 had developed from eggs deposited September 5, and hatched September 12, 

 emerged May 29. 



To show more clearly the times at which the moths appear I have com- 

 piled the following table from breeding cage records for 1898-99. Beginning 

 July 7, 1898, when the first wormy apples were found, infested fruit was 

 gathered from time to time throughout the season and placed in cages. 

 The same process was followed in 1899. Careful record of the dates of 

 appearance of the moths was kept throughout the fall of 1898. In 1899, 

 during my absence the records were efficiently kept by Mr. W. J. Gilstrap, 

 a student assistant, until September 7, when he resigned. However, on 

 September 2, he observed that many moths of the second generation had 

 not emerged. It is, therefore, probable that they would have continued to 

 emerge at least until September 15, as in 1898. 



Bui. 30, New Series, Div. Ent. U. S. Dept. Agr. 



