214 OUR HOUSEHOLD INSECTS 



born and bred in the open air, is, it would seem, more 

 remarkable than that the association should be a con- 

 tinuous and permanent one. As the nature of the food 

 on which they are reared necessitates, as a rule, that 

 they should pass through their earlier stages exposed, 

 it is rather curious that the perfect insects should 

 not confine themselves to similar localities, but should 

 also enter our dwellings, and often in such surprising 

 numbers. 



Nor is it, again, that they are so much more abundant 

 than all other species, and that, therefore, mere excess 

 of numbers causes them to be the species represented 

 indoors : that, in other words, we simply get the over- 

 flow from outside. Of course they are abundant this 

 is implied in their being pests but there are other 

 species equally so, of which it is the rarest occurrence 

 to find a specimen in the house. Take, for example, 

 the case of Sarcopliaga carnaria, the flesh-fly, which has 

 been several times referred to already. This is an insect 

 of most extraordinary fecundity : it is said that as many 

 as 20,000 eggs have been found in the ovaries of a single 

 female, and. in consequence, it is an extremely common 

 fly; but though its habits are similar to those of the 

 bluebottle, and it swarms round human dwellings, it is 

 very seldom seen indoors. The facts of its distribution 

 seem to show that it is far less dependent on man, and 

 far more inclined to ignore his movements, than our 

 household pests. It is an extraordinarily hardy insect, 

 and shows wonderful powers of adaptation to circum- 

 stances. Even in the matter of food, which is often 

 such a critical point with a larval insect, it can stand 

 some degree of variation, feeding not merely on meat, 

 either fresh or putrid, and wounds and ulcers on men 

 and other animals, but even on decaying vegetable 



