﻿10 THE ENTOMOLOGIST. 



None of the larvce that died were small when found, and were 

 very active, moving freely up and down their burrows. Of the 

 seventeen that had already spun up not one showed any inclina- 

 tion to move about, but in one or two instances, when the lower 

 portion of cocoon was damaged, the damage was at once repaired. 

 It therefore seems that T. crahroniformis, here at any rate, spins 

 up ready to pupate either in autumn or beginning of winter, and 

 not in spring as stated by other writers. It seems, therefore, 

 that those larvae that do not spin up before December of one 

 year continue to feed during the following summer, and have a 

 two-year cycle at least from egg to perfect insect. 



S. cynipiformis is the commonest of the Sesiidse in this area 

 of Kent. Numerous woods were cut down during the winter 

 1912-13, leaving stumps of old oak trees in the ground. These 

 trees were all sawn off close to the ground, leaving some six to 

 nine inches exposed and covered with bark. I inspected a large 

 number of these stumps during March and April of this year, 

 and again during June and late July. During March and April 

 I took out some 120 larvse of all stages, some quite small — less 

 than a quarter of an inch — others apparently full-fed. All, large 

 and small, had spun themselves into a cocoon at the end of 

 burrow with frass round it. I put them into a zinc box with 

 holes in it for drainage ; filled box with some oak sawdust and 

 large pieces of bark. This box I put into a tin, covering with a 

 bell-glass. I put the whole on the hot-water tank of the house 

 and left them there, constantly moistening the sawdust. I 

 looked at them daily and found they had all tunnelled into the 

 oak bark, and continued to feed, eventually pupated and 

 emerged. I bred out on an average seventy-five per cent, of 

 larvse, large and small. At the end of April all larvse in stumps 

 had grown considerably. I repeated the operation with similar 

 results, but with a larger percentage of moths successfully 

 reared. During June I only found full-fed larvse and pupse. 

 Towards end of July I only found empty pupa cases — not a 

 single full one and no larvse. From this we can be sure that 

 Col. Nurse's deductions are correct — that the larval stage does 

 not last over one year. 



S. culiciformis is almost as common here in larval stage as 

 .the last. I overlooked numerous woods where birch trees had 

 been cut down during the winter 1912-13, through the spring 

 of 1914. From the beginning of February to the end of March 

 I went out, stripped the bark of the stumps about once a week, 

 and obtained over one hundred larvse. All had spun up and 

 were resting through the winter in their cocoons. I forced these 

 in the same manner as I did larvse of other Sesiids, and about 

 seventy per cent, emerged within a month. When I searched 

 for them during third week in April I found they were turning 

 to pupse, about fifty per cent, having already changed. I again 



