298 Agricultural Experiment Station, Ithaca, N. Y. 



(Figs. 55 and 58). By May 20th, its hibernating case with its 

 spring additions (Fig. 60) is discarded for another and larger cigar- 

 sliaped case (frontispiece and Fig. 58) which the caterpillar deftly 

 makes from pieces of the npper and lower skins of the leaves 

 (Fig. 61). Protruding themselves from these cases, . they 'eat 

 through one skin of the leaf and mine out the inner tissues over an 

 irregular area, as far as they can reach and not let go of their case 

 (Fig. 63). In the latter part of June, they cease feeding, securely 

 fasten the cases to the leaves or branches, and change to pupae 

 within. The moth (Fig. 56) emerges in about three weeks, and 

 soon lays minute, pretty, yellow, pitted eggs (Fig. 64) among the 

 hairs on the young leaves. The egg stage lasts about two weeks, 

 the little caterpillars emerging about July 15th. They work as 

 miners in the tissue of the leaf for two or three weeks, then aban- 

 don their mining habit and construct their curious little curved 

 eases from bits of the skins of the leaves. By September 15th, 

 they have all migrated to the twigs, where they pass the winter in 



these cases (Fig. 59). 



]^atural Enemies. 



We have not met with any natural enemies of this case bearer, 

 but in 1891, Mr. Fletcher bred a 'few minute hymenopterous 

 (Chalcid) parasites from the cases in Canada. 



How to Combat it. 



It is practicable to fight this case bearer in its caterpillar stage 

 only ; and it is then so well protected in its case as to render its 

 •destruction dependent upon very thorough work. 



Extensive experiments in Canada by Dr. Young, of Adolphus- 

 town, Ont., have demonstrated that there is but little hope of 

 reaching the caterpillars while they are in their winter quarters 

 on the twigs. Dr. Young sprayed his trees in the winter with 

 kerosene emulsion, using it both cold aud warm (probably diluting 

 it with nine parts of water), and failed to destroy the cater- 

 pillars in their little cases. Perhaps a stronger emulsion might 

 have been more effective, but it is very doubtful if any spray will 

 reach the insect in its winter quarters. Thus the only time when 

 it can be effectively reached is when it is actively feeding in the 

 spring. 



We have had no opportunity of carrying on any experiments 

 against the insect; but we advised all of our correspondents in 



