120 SECOND ANNUAL REPORT OP 



tached to it, the insect which attacks it cannot be classed among the 

 injurious species. The plant has a peculiar wooly or hairy whitish- 

 green appearance, and in the month ot September its leaves may fre- 

 quently be found rolled up after the fashion shown at the left of Fig- 

 [Fig. 95.] ure 9^ with the larva inside. 



^'' ^^few * "b^ r ^'^ s r °H °- t' ,e l ea * i s S en " 



^V /„dS$k iiliiF^ era ^ v q i 'ite uniform, and is 



made in the following man- 

 ner : Extendingitself on the 

 midvein, with its head to- 

 wards the base of the leaf, 

 the larva attaches a thread 

 to the edge, at about one- 

 fourth the distance from the 

 base to the point. By a 

 " © tension on this thread, it 



draws this edge partly toward the opposite one, and fastens it there, 

 being assisted in the operation by the natural tendency of the leaf to 

 curl its edges inwards. Fastening a thread here, it repeats the ope- 

 ration until the edges meet, and then it proceeds to firmly join them 

 nearly to the apex, leaving a small aperture through which to pass 

 the excrement. During hot days the larva remains concealed in the 

 leaf, and towards evening comes out to feed, though sometimes it 

 feeds upon its house, eating the leaf down halfway from base to point. 

 It then abandons it and rolls up a new one. In the breeding cage, 

 when placed in a cool shady room, the larva seldom rolls up the 

 leaves, but feeds at random over the plant, and when at rest simply 

 remains extended on a leaf. From this we may infer that its object 

 in rolling the leaves is to shield itself from the rays of the hot August 

 and September sun; for the plant invariably grows on high naked 

 prairies. 



The young larva has a large head, larger than the third segment, 

 which is the largest in the body. The head preserves its general form 

 through the successive moults ; it is light bluish, thickly covered with 

 papillre of a dirty-white color, and there are also a number of light 

 orange papillas of a larger size scattered among them. The skin of 

 the caterpillar is green, but the general hue is a dirty-white, owing to 

 the entire surface being very closely studded with white or whitish 

 papillae with dark-brown ones interspersed. These prominences are 

 hemispherical, hard, opaque, shining, and the larva feels rough and 

 harsh to the touch. 



At each moult some of these papillae disappear, especially all the 

 brown ones, the body increases in size so that the head is smaller than 

 the third segment, the green color of the skin becomes more appar- 

 ent, the body is softer to the touch, and the whole larva assumes a 

 neater appearance. 



