HABITS OF TWO PARASITES OF BLOW- FLIES. 



205 



The pro-piipal stage, i. e. after spiiniiiig tlie cocoon, niny last a, 

 fevv days or several iiioiitlis. In two specific instances observed 

 the pro-pupa changed to the pupa, the one 2 days after it was 

 exposed in the puparium, the otlier 5 days after. 



Some hibernating larva^ from tlie stock have been observed in 

 pupai'ium whicli they liad not yet lined, although four months 

 had elapsed since the date of oviposition. 



The Pupa. — Tlie pupa (text-fig. 7) is loose within the cocoon, 

 and is capable of slight movement. Tlie meconium now appears 

 to become slightly compressed, due to the process of meta- 

 morphosis. 



Text-figure 7. 



. Lateral and ventral as-pect of jmpie of A. luandncdtor. Greatly magnified. 

 The figure on left a few da^ s older than that on right. Original. 



During the whole })upal stage the afore-nientioned large white 

 particles are visible, at first scattered about in the abdomen and 

 later can be seen between the tergites and sternites. 



The pupa, which is glabrous throughout, is, at first, creamy 

 white with reddish-brown eyes and ocelli , in a few days the head 

 and thorax turn grey, gradually becoming black; meanwhile, the 

 sternites and tergites — widely separated over the distended 

 abdomen — begin to turn grey, and the eyes and ocelli darken ; 

 the legs and antenna^ similarly begin to show the coloration of the 

 adult, likewise the mouth-parts. The last larval skin splits across 

 the head dorso-ventrally backwards, and then appai-ently slips 

 back to the apex of the abdomen, from which it is disengaged by 

 movements of the abdomen and antenme of the male or the 

 ovipositor of the female. In no instance has the larval exuvium 

 been found attached to the pupa, but lying in a crumpled mass 

 beyond the apex of its abdomen. 



The length of the pupal stage was, in two specific instances, 

 found to be 7 and 10 days respectiveh' with a mean temperature 



