OF WASHINGTON. 9P 



cases, both of which tends to make the exteriors regular. When 

 bits of sticks are used they are placed, as with leaves, at right 

 angles to the axis of the case. Sticks as large as one-fifth of an 

 inch in diameter are often used. The larva* were observed to eat 

 out a notch in the inner side of the stick when in place. It is 

 quite a task for one to fasten one of these large sticks securely, 

 and many times the larvae get into difficulties by adding sticks 

 that are so bouyant that they come up to the surface. The insect 

 thrusts its body out of the case, jerks and beats the water vio 

 lently until a chance foothold is secured, when it crawls to the 

 bottom. The larvae immediately begin to build themselves a 

 new case when deprived of the old one, and can complete a case 

 in one night. Experiments were tried by giving the larvae small 

 stones with which to build a case, and in no instance were the 

 larvae successful. Snail shells with living snails are sometimes 

 used in the cases. A cherry-pit was noted. One larva used two 

 wheat kernels which sprouted and caused some inconvenience to 

 the occupant. When cases were given naked larvae they imme 

 diately crawl into these head first, but in a short time one finds 

 them in their normal position. 



The contents of the alimentary canal of several larvae were ex 

 amined. In all instances vegetable matter such as leaves and 

 wood was found. The alimentary canal is remarkable on ac 

 count of the great development of the muscles, particularly the 

 circular. 



The first pupation was noted on April 28, and practically all 

 had pupated by May :6. Strong silken nets were found at either 

 opening of the case ; the cephalic opening being largest. In an 

 aquarium a few cases were found attached to the sides of the glass 

 jar, while in the pond they could attach themselves to the lower 

 side of leaves. Some were found standing on end in the bottom 

 of the pond. In all places it was noted that the insect and its 

 case were in such a position that no mud could enter the case by 

 the circulation. 



The pupae are very delicate, of a white, and later of a pink, 

 color. The most interesting structure is the lateral fringe of stiff' 

 hairs which was noted in the larvae. In the pupse these hairs 

 are larger and are present on the caudal end as well as the lateral 

 margin. By placing a case, containing a pupa, in a dish of water 

 containing carmine the circulation of water through the case was 

 observed. Without doubt this circulation is produced by a gen T 

 tie undulatory motion of the abdomen, which action would be 

 greatly aided by the fringe of hairs. 



The first adult emerged May 29. The pupa? break the ceph 

 alic net and swim to some projecting stick upon which they crawl 

 out of the water. The skin splits in the usual way and remains 

 fastened upon the stick by the claws for some time. Many adults 



