The CANADIAN BNTOMOLOGlSt. 233 



Food-plants. — Though we have every reason to beUeve from the facts 

 as given that Vaccmmtn vacillans is a natural food-plant, I am not 

 satisfied that it is the only local food-plant. I have spent many hours, 

 both of daylight and at night, in the search for augustus larvse on the same 

 plant, and have never yet found a caterpillar of Henrici. Mr. Edwards's 

 discovery of a full-grown larva on wild plum suggests that other species of 

 Primus may be the food, and this is borne out by the coloration of the 

 insect, which renders it very conspicuous on a green surface, and the rosy 

 tints here and there on vacilla?is are altogether too ill-defined to make it 

 any the less so on that plant. Although wild plum is not found here- 

 about. Primus pennsylvanica and P. cimeata* are common, and are likely 

 to prove the usual food-plant locally. 



I was unable to secure any wild plum, or I should have tried my 

 larvae with it ; they would not touch cultivated varieties when Vaccinium 

 was to be had, and I did not risk losing them by removing the latter from 

 the breeding-glasses. 



Pupation. — When ready to pupate the caterpillar descends from the 

 plant and turns to chrysalis among the twigs and dried leaves on the 

 ground. When from their actions it became evident that my larvae had 

 finished eating, they were placed in a box with a plentiful supply of 

 rubbish, among which there chanced to be an old alder leaf caked over 

 and nearly black with dried "honey-dew." This was found by all three 

 caterpillars, and on the lower surface (as it lay) they took their stations 

 preparatory to casting the last larval skin. 



The Change to Chrysalis. — I witnessed the ecdysis of the chrysalis 

 of all of the three insects which pupated, though the greater part of the 

 precursory peristalsis took place during my absence. The skin split first 

 along the thoracic dorsimeson, and was more or less torn as the soft pupa 

 worked its way out. The latter was dingy gray-green on the wing-cases 

 and abdomen ventrally, dusky orange-brown on the dorsum. The series 

 of pits (distributed as in augustus) were not as marked as would have 

 been expected from the deep fovese of the larva, the pigment in them was 

 dark brown instead of black, and appeared to be absent in some. By 

 morning the chrysalids were brownish-yellow, sprinkled with pitchy spots, 

 the pits scarcely noticeable, the straw-coloured spiracles standing out in 

 sharp contrast. During the succeeding 24 hours the skin became steadily 

 darker, the spiracles remaining light until the final coloration was attained. 



*Recently separated from P. piimila according- to Britton and Brown. 



