40 THE PARASITES OF THE HONEY BEE. 



transformations just as the exhausted host is ready to die, issue 

 from their bodies as flies, closely resembling the common house- 



fly. 



A small fly has been found in Europe to be the most formid- 

 able foe of the hive bee, sometimes producing the well-known 

 disease called " foul-brood," which is analogous to the typhus 

 fever of man. 



This fly, belonging to the genus Phora (Fig. 32, Phora incras- 

 sata,; a, larva; b, puparium; c, another species from Mammoth 



33. Phora and its Young. 



Cave), is a small insect about a line and a half long, and found 

 in Europe during the summer and autumn flying slowly about 

 flowers and windows, and in the vicinity of beehives. Its white, 

 transparent larva is cylindrical, a little pointed before, but 

 broader behind. The head is small and rounded, with short, 

 three-jointed antennae, and at the posterior end of the body ai-e 

 several slender spines. The puparium, or pupa case, inclosing 

 the delicate chrysalis, is oval, consisting of eight segments, 

 flattened above, with two large spines near the head, and four 

 on the extremity of the body. 



When impelled by instinct to provide for the continuance of 

 its species, the Phora enters the beehive and gains admission 

 to a cell, when it bores with its ovipositor through the skin of 

 the bee larva, laying its long oval egg in a horizontal position 

 just under the skin. The embryo of the Phora is already well 

 developed, so that in three hours after the egg is inserted in the 

 body of its unsuspecting and helpless host, the embrj^o is nearly 

 ready to hatch. In about two hours more it actually breaks ofi" 

 the larger end of the egg-shell and at once begins to eat the 

 fatty tissues of its victim, its posterior half still remaining in 

 the shell. In an hour more, it leaves the egg entirely and buries 

 itself completely in the fatty portion of the young bee. 



