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but some differences. When first suspended, whicli it did from a pad 

 of white silk, the larva took the attitude of an oval, the head brought 

 near 12th segment ; a few hours later that of figure 6 ; and finally of 

 a right angle, the head continuing to droop. During the last two 

 hours there was a constant move of the head, which seemed to rub 

 itself on the anterior legs, and several times and vip to within one-half 

 hour of the change, the larva doubled itself up and brought its head 

 to the button of silk, as if greatly anuojed at something there. This 

 I noticed in both the larvae observed. Finally, the body was con- 

 tracted and lifted up as in Grapta, and a slight creej)ing movement 

 was seen, but there were no twitchings or twistings as in Grapta. 

 The creeping became stronger, advancing in waves, and the strain on 

 the anterior segments became severe, till the skin burst on the dorsal 

 line of 2, 3, and 4, and the top of the head also was rent. The slit was 

 oblique, and the ventral side was covered three segments beyond the 

 dorsal. When the body was exposed on dorsum at 10 and 11, the 

 ventral side was covered at 8 and 9, and the skin fitted tight, so that 

 as the body bent back in the movement to free the tail the skin was 

 pinched between the segments. The struggle became violent, the 

 segments all along the abdomen stretching to the utmost, and then 

 contracting forcibly, one telescoping into the next; and in tliis the slcin 

 folloived the segment, andioas draion in and held for an instant. As this 

 movement ran through the segments successively, the skin was pinched 

 at one joint after another, and the chrysalis was evidently rising 

 towards the silk as described by Dr. Harris. Unfortunately I was able 

 to see the transformation in but two examples of ArcMppus. In the 

 first one, I set myself to see how the whole change must have appeared 

 to Dr. Harris, as he had described it minutely. In the next one I 

 lifted the flap of skin till I saw the ligament. In so doing the whole 

 thing unhooked from the silk, and as it lay in my hand I pulled back 

 the skin and was able to look at the ligament with a lens. I also lifted 

 the chrysalis by the skin, and the ligament did not part. It did so 

 afterwards only by a strenuous effort of the chrysalis, and then remained 

 distended, with its forks in shape. The nature of this organ must be 

 determined by further observations. I had sent to a friend, who is an 

 experienced microscopist as well as entomologist, a chrysalis of inter- 

 rogationis which had been dropped in glycerine at the crisis of pupation, 

 and he writes me thus : — " I have examined the preparation, which was 

 in good condition except the separation of the chrysalis from the skin. 

 I see what you call the two ridges, which exist also in the caterpillar 

 and have between them the anus in both caterpillar and chrysalis. 



