INVESTIGATION OF LIFE HISTOEY. 27 



brown. Caudal appendages relatively shorter than in preceding stage, each provided 

 dorsally with a stout but short protuberance on its inner third, which bears a stout 

 bristle. 



Third-Stage Larva. 



More robust than in previous stage. Average length 25.8 mm. Average width 

 5.7 mm. Body shining black in color, mandibles, legs, mouth parts, antennae, and 

 lateral and ventral abdominal markings dark brown. Prothorax much wider than 

 long, wider behind . Dorsum of last abdominal segment and anal proleg chestnut-brown. 

 Dorsal abdominal plates nearly truncate behind, lateral margins of each raised and 

 thickened. These margins more prominent on the last three segments. On the 

 penultimate segment, each dorso-lateral margin forms a stout, blunt, overhanging 

 fold, while on the last segment each margin is drawn out into a stout tooth, pointing 

 backward. 



Median dorsal line prominent on all segments except the last. Caudal appendages 

 short, quite erect, with a large, stout dorsal tooth, and a small lateral tooth, both of 

 which are provided with spines. 



The Process of Molting. 



The larvae are active and feed voraciously; during this time their 

 bodies are greatly distended and the white portions of the integument 

 render the insect quite conspicuous. Just before the molting begins 

 they become sluggish and do not move about unless disturbed. The 

 body shortens and becomes thicker than normal. By moving the 

 head and posterior end of the body downward and toward each other 

 at regular intervals the integument is ruptured along the dorsal line 

 of all the thoracic segments. The head, mouth parts, and legs are 

 gradually withdrawn and a pure white larva crawls from the old skin. 

 Usually the sutures on the top of the head are broken as the larva 

 makes its escape. The molting process requires but a few hours, and 

 this is fortunate, as the larva is practically helpless while the trans- 

 formation is being accomplished. 



In nature the larvae often molt under litter on the ground, but 

 when they are feeding on caterpillars on the trees molting takes place 

 in holes or cavities in the trees . among masses of gipsy moth pupae, or 

 even in crevices of the bark. It is probably true that many of the 

 larvae pass through the two molts without descending to the ground. 



Length of Time in Larval Stages. 



The duration of time between the molts is influenced greatly by 

 high temperatures and food supply. In the spring of 1908, careful 

 records were kept of a number of larvae which hatched from eggs 

 deposited by beetles that were removed from hibernation in March 

 and early April. One of the objects of the experiment was to deter- 

 mine the length of time required by larvae that hatched early in spring 

 to pass through their transformations, and further, to determine the 

 possibility of such larvae developing a brood of beetles which would 

 become active and reproduce during the summer. A considerable 



