New York Agiucultuual Expekimknt Station. 281 



Albion 01' Geneva. Some indication's of tlie time of egg laying 

 were given by the evident age of some of tbe larvse found Octo- 

 ber 29. An occasional one less than half grown was found, but 

 most of them were full grown and a number had transformed 

 to pupae. 



TliG mine. — The young larvse feed upon the parenchyma usu- 

 ally in the upper side of the leaf. The skin is left intact. The 

 final result is a tentiform mine, which distorts the leaf as shown 

 at Plate XXXIX, Fig. 4. In this mine the larva lives and feeds 

 until full grown. Evidently no attempt is made to keep it clean, 

 as the droppings were always found scattered about, as shown 

 at Plate XXXIX, Fig. 2. This picture shows one of the mines 

 cut open and much enlarged. 



When full grown they Idave the old mine to pirepare for pupa- 

 tion. The manner of doing this is shown by a number of full 

 grown 'caterpillars which were placed on fresh leaves in the 

 laboratory October 31. They did not mine into the tissue, but 

 selecting the slightly curled edges of the leaves and placing the 

 body in a position nearly parallel to the side and far enough 

 away so that by bending the anterior two-thirds of the body the 

 head would touch the point of one of the serrations, begin to 

 spin strands of silk from this point to the main body of the leaf. 

 There were eight caterpillais, and all of them followed this plan. 

 At Plate XL, Fig. 1, a single point is shown, much enlarged, 

 held by the threads. The larvje worked very rapidly. In about 

 half an hour m,ost of them had made a network of silk extend- 

 ing about half an inch along the sides of the leaves. They 

 then began to work from the under side of the silk, and as 

 they clung to it began to spin as before. Brunn* suggests that 

 the weight of the caterpillar's body causes the margin of the 

 leaf to bend over. This undoubtedly has some effect, but as the 

 caterpillars feed on the parenchyma, under the tent, the wither- 

 ing tissues may play an important part in producing the desired 

 result. In about three hours most of the tents had the appear- 



nSecond Rci;oi't Cornell Univ. Agr. Exp. Sta., p. 151. 



