CHEESE-FLY. 263 



larvae common in cheese, well known under the name 

 of hoppers, will be somewhat surprised to hear the 

 illustrious Swammerdam say, " I can take upon me 

 to affirm, that the limbs and other parts of this maggot 

 are so uncommon and elegant, and contrived with so 

 much art and design, that it is impossible not to ac- 

 knowledge them to be the work of infinite power and 

 wisdom, from which nothing is hid, and to which 

 nothing is impossible."* But whoever will examine 

 it with care, will find that Swammerdam has not 

 exaggerated the facts. 



The cheese-fly {Piophila Casei, Fallen) is very 

 small and black, with whitish wings, margined with 

 black. It was one of those experimented upon by 

 Redi to prove that insects, in the fabric of which so 

 much art, order, contrivance, and wisdom appear, 

 could not be the production of chance or rottenness, 

 but the work of the same omnipotent hand which 

 created the heavens and the earth. This tiny little 

 fly is accordingly furnished with an admirable instru- 

 ment for depositing its eggs, in an ovipositor, which 

 it can thrust out and extend to a great length, so 

 that it can penetrate to a considerable depth into the 

 cracks of cheese, where it lays its eggs, 256 in number. 

 " I have seen them myself," says Swammerdam, 

 *' thrust out their tails for this purpose to an amazing 

 length, and by that method bury the eggs in the 

 deepest cavities. I found in a few days afterwards a 

 number of maggots which had sprung from those eggs, 

 perfectly resembling those of the first brood that had 

 produced the mother-fly. I cannot but also take 

 notice that the rottenness of cheese is really caused by 

 these maggots ; for they both crumble the substance 

 of it into small particles, and also moisten it with 

 some sort of liquid, so that the decayed part rapidly 



* Bibl. Naturae, vol. ii. p. 63. 



