HABITS UF TWO PARASITES OF BLOW-FLIES. 



205 



The pro-pnpal stage, i. e. after spinning tlie cocoon, may last a 

 few days or several months. In two specific instances observed 

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

 exposed in the puparium, the other 5 dnys after. 



Some hibei-nating larvae from the stock have been observed in 

 pupari-am whicli tliey liad not yet lined, although four months 

 had elapsed since the date of oviposition. 



The Pupa.—T\\Q 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 tlie process of meta- 

 morphosis. 



Text-fio'ure 7. 



Lateral and ventral aspect of jJiipiE of A. manducator. Greatly niag-nified. 

 The figure on left a few da3s older tliau that on right. Original. 



Daring the whole pupal stage the afore-mentioned large white 

 particles are visible, at lirst 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 thoi'a.x turn grey, gradually becoming black; meanwhile, the 

 sternites and tergites — widely sepaiated over the distended 

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

 the legs and antennfe similarly begin to show the coloration of the 

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

 the head dorso-ventrally backwards, and then apparently slips 

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

 movements of the abdomen and antennte 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 respectively with a mean temperature 



