PERFECT INSECTS WITH THE LARVAL HEAD. 9 



tion of other parts ; even if the untransformed parts are important to 

 the life of the animal. He believes this to be a natural consequence of 

 the segmentation of the body of the arthropods. 



2. The accidentally covered parts nevertheless go through all trans- 

 formations which are necessary for the insect to arrive at the imago 

 state. The second conclusion is of course not to be accepted, if the 

 facts recorded by Mueller are adopted. 



Morpho Eurylochus. 



Among about a dozen specimens of this butterfly brought home by 

 Professor L. Agassiz from Brazil, one male has retained the head of the 

 caterpillar. The specimens are from Canta Gallo, communicated by 

 Dr. Teuscher. Their perfect condition leads me to suppose they were 

 reared from the chrysalis. 



The quoted male is in perfect condition, and, as all others, entirely 

 well developed in size and in colors. The head of the caterpillar is 

 retained and perfectly preserved in shape and in color; the minute 

 yellow hairs which cover the head are in good condition, and the 

 spines are scarcely crumbled. Beneath the head the mentum is 

 broken off near the prothorax. Its lateral sutures are separated, and 

 the mentum hangs down as a kind of trap-door, being united with the 

 head only by a small anterior lobe. This kind of adjustment leads me 

 to suppose that the mentum was broken by the pushing out of the 

 spiral tongue of the imago. The opening is large enough to show that 

 the head of the caterpillar is empty inside. The skin between the 

 head and the prothorax is still preserved in the shape of a contracted 

 ring, which is open only for a small space beneath, where the mentum 

 is separated. The large dorsal plate of the prothorax is present, and 

 covers loosely the thorax of the imago ; on the left side the external 

 third is wanting. The palpi are rejected to the thorax, but the right 

 palpus has the two basal thirds covered by the skin of the caterpillar, 

 which is connected with the dorsal part of the prothorax. Behind the 

 palpus and rather near to it can be seen the free foreleg of the right 

 side. Its limbs are well developed, neither as stout nor as hairy as in 

 the other specimens. The left palpus, though not covered, seems to be 

 shorter and less hairy than the right one. The left foreleg is covered 

 by the femur of the middle leg. I am not able to state whether any 

 part of the skin of the chrysalis, either beneath the dorsal plate of the 

 prothorax on the middle and on the right, or on the entirely free left 

 side of the thorax, is present. Perhaps the skin of the chrysalis is 

 broken oft' just at the ring formed between the head and the prothorax. 

 I am unable to see the skin of the chrysalis inside of the head of the 



