OVO-VIVIPAROUS INSECTS. 



Ill 



third of an inch, and he computed that there were 

 about 20,000 young in the coil*. When this extra- 

 ordinary fecundity is considered, we need not wonder 

 at the countless swarms which appear as if by magic 

 upon a joint of meat during hot weather. 



Like most female insects, the mother-fly dies in a 

 few days after giving birth to her numerous brood ; 

 but, iHilike the oviparous flies, she seems to take a 

 considerable time to deposit the whole. It would be 

 impossible indeed for her pouch to contain the larvae 

 if they were all hatched at the same time ; and there- 

 fore it has been so ordered by Providence that they 

 should arrive at maturity in succession. From the 

 early death of the mother, Reaumur conjectured that 

 they did not scruple to eat their way through her 

 bowels ; but he disproved his supposition by a most 

 decisive experiment. He took a fly which had already 

 deposited a few larvse, and closed the natural opening 

 of the pouch with sealing-wax, so that it was impos- 

 sible any more could make their exit there. The 

 mother lived several days longer than she would 

 have done, had she been left at liberty to produce 

 her young; but not one of them attempted to force a 

 passage, after being slmt up for ten days. 



Another large grey fly with brick-red eyes (species 



A B 



A, large grey blow-fly, with the abdomen opened, showing the 

 young maggots. B, breathing apparatus of the maggot of a 

 large grey blow-fly. 



* Reaumur, Mem. iv. 417. 



H 2 



