THE FLY. 65 



The questions that you will naturally put to your- 

 self when you enter your breakfast-room^ and find 

 that the little intruders have already taken possession 

 of your choicest viands, are : " Whence come these 

 myriads of insects, of which, a few days since, scarcely 

 a single one was visible ? and what has been their 

 previous career?" We shall endeavour briefly to 

 answer these queries, and to detail a few of the best- 

 known facts in regard to the life-history of the Fly. 



" Few persons are aware," (to quote the words of 

 an old G-erman writer* on the subject) " that these 

 insects, which swarm around their heads, had pre- 

 viously crept imder their feet;" but that such is the 

 case, we have already mentioned in. treating of the 

 metamorphoses which the Fly undergoes, and of the 

 analogies that exist between its larva and the fully- 

 developed Worm (Letter IV.) ; and a reference to 

 this portion of the subject leads us first to consider 

 the mode of reproduction in the Fly, and of the 

 extraordinary powers that it possesses to multiply its 

 species. 



As we have glanced at the general anatomy of the 

 Fly, we may here mention, with reference to its 

 organs of reproduction, that they are never united in 

 the same creature, as we found to be the case in the 

 Worm; but in this insect the sexes are perfectly 

 distinct, the female beiag recognizable by the pre- 



* Keller, ' GescMchte der gemeinen Stubenfliege' (trans. 

 " History of the Common House-fly." A copy may be found in 

 tbe British Museum). 



