HABITS OF TWO PARASITES OF BLOW- FLIES. 



219 



pupariiim — with its posterior segments siuTor.nded by the me- 

 conial discharge, winch dries rapidly. So that when the larval 

 skin bursts and recedes, the pupa (text-fig. 15), which does not 

 entirely free itself from the larval exiivium, consequently becomes 

 anchored to the meconium. This has been observed by emptying 

 the larval contents of a puparium into a small glass tube. 



Text-figure 15. 



Pupa of K. hrevicoryiis. Groatlj' magnified. Original. 



The duration of the pupal stage is variable. "This was 

 obtained in one case only. A larva pupated during the night" of 



Sept.17-18, 1908, Tiie resulting adult female emerged 



at 10 A.M. Sept. 23, 1908, making a pupal stage of approximately 

 5;^ days. The average length of this stage for the first spring 

 generation (17 cases) was 9 days (May 14-23, 1909)" (6). 

 Another observer states : — " The pupal stage occupies about 

 five days" (8). Those pupje observed by the writer ranged from 

 8-12 days. " When first formed, the pupse are yellowish white, 

 the eyes garnet, with some duskiness at the caudal edges of 

 the abdominal segments soon afterwards; the mandibles, legs, 

 a,ntenn£e, and wing-pads gradually become dusky, and about 

 48 hours previous to eclosion, the head, thorax, arid abdomen, in 

 succession, begin to show dai-k colour, the head and thorax 

 together becoming a, deep black before the abdomen shows very 

 much colour, and then, after about 6 hours, the latter tra*ns 

 gradually but lupidly black. About 20 hours l)efore eclosion the 

 colour is jet-black, which just pi-eceding emergence changes nearly 

 to the colour of the mature adult. At eclosion the adults are 

 fully coloured.'*' (6.) 



The pupal exuvium, which is very stiff, is a golden brown, and 

 does not recede as in the Braconid, but appears to be broken up 

 in parts; pieces which retain the outline of the antennie are 

 frequently found loose; similarly, pieces from the head and legs 

 can be found; the abdominal portion seenis tliinner, and is usually 

 attached to the apex of it when the insect emerges. 



