LAKVAL HABITS OF THE TIGER BEETLES. 163 



At emergence, the eyes are pale brown and gradually become darker by 

 the development o£ the iris and retinal pigment, until the end of about ten 

 days when the process appears to be complete. Differentiation of the 

 appendages of the adult begins at their distal ends. Cuticular pigment 

 develops only when the cuticula is mature. The appearance of pigment is 

 coincident with final hardening. At the end of twelve days pigment has 

 appeared on the tips of the mandibles and a little later on the tips of the 

 mandibular teeth. It proceeds ffbm these toward the proximal portions, and 

 by the 13th or 14th day the process is complete. On or about the 13th day 

 the tarsal claws are pigmented, and a day or two later the proximal portion 

 of the tibia shows pigment which moves toward the more distal portions. 

 Coincident with the development on the tibia, pigment appears on the outer 

 border of the trochanters and later develops at the attachment of the principal 

 muscles and tendons of the leg (PL 24. fig. 14). 



The Last Ecdysis. — The first movement possible in the pupa is that of the 

 tarsal claws. The legs, early in the process of moulting, are moved outward 

 from the body and slightly straightened. For this the trochanter muscles 

 a.nd the muscles of the femur are used. Their attachments are hardened and 

 pigmented and movement is accordingly possible. By vigorous movements, 

 -especially of the legs and mandibles, the pupal skin is ruptured and the 

 continuation of the movement frees the imago. 



The bristles of the adult assist in the removal of the exuvium. Their 

 arrangement is well illustrated in the legs (PL 24. fig. 14) and other 

 appendages, where they occupy much space inside the pupal skin. This 

 function of the bristles was suggested by Miall and Denny in their work on 

 the Cockroach. 



The Imago. — After emergence, the imago remains in the cell for several 

 days, the pigment of the body meanwhile developing. The only specimen of 

 purpurea that was brought to maturity emerged on August 11th and about 

 eighteen hours afterwards had apparently reached an adult colour. It lived 

 for ten days longer, during which time it underwent a series of colour-changes 

 that will be described elsewhere. 



In nature, adults appear in the latter part of each August. They feed 

 during the early fall, and in early October dig holes in some little bare bank 

 in a meadow or go into the hole of some other insect for hibernation. They 

 have been dug, in late October, from such situations, being apparently helpless 

 from the cold. Specimens hibernating in captivity appeared in the latter part 

 of March. They reach sexual maturity late in April, lay eggs and die. 



Summary and Comparison. — The life-history of Cidndela jmrpurea may be 

 summarized as follows : — The eggs are laid in May; larvge reach the last stage 

 in August, hibernate, begin to feed again in April and pupate in July ; the 

 adults emerge in August, feed for a time, hibernate and come out in the 

 second spring still sexually immature, reach maturity in the first warm days 



