202 MUSCID2E, OR FLY-TRIBE ; MAGGOTS. 



a few of them the larvae are aquatic, and the posterior part of 

 the body is prolonged into a respiratory tube, whence they have 

 received the name of " rat- tailed " larvae. This is the case with 

 the Eristalis above represented, and with several allied species. 



798. The form and habits of the family MUSCIDJE, or Fly 

 tribe, are generally known. The family is an extremely nume- 

 rous one, above 1700 species having been recorded as existing in 

 Europe, of which about half are natives of this country ; and 

 there are probably at least as many more, which have not been 

 described. The strong general resemblance which exists among 

 all the species, together with their small size, makes it difficult 

 to discriminate them readily. The larvse of these insects, com- 

 monly known as maggots^ are soft, worm-like, footless grubs, 

 possessing on the head a couple of retractile hooks, by which 

 they can cling to the substances on which they feed. They 

 devour various substances, both animal and vegetable, living, 

 recently dead, or far advanced in putrefaction. The eggs are 

 deposited by the female (as in other instances) in the neighbour- 

 hood, or in the very substance, of the food which is adapted for 

 the support of the larva, however little this may be to its own 

 liking. Some of these larvse are remarkable for their leaping 

 powers, whence they are commonly termed " hoppers." This 



is especially the case 

 with the larva of 

 the Piopkila casei, 

 or Cheese-hopper ; 

 whose mode of 

 springing into the 

 air is very curious. 



FIG. 529.-1. The CHEESE-HOPPER preparing to spring.- When preparing to 

 2. Natural size of the Larva. 3, 4. The Fly to which ], ap it first raises 

 it is transformed : natural size and magnified. 



itself on its tail ; 



in which position it is enabled to balance itself, by means of 

 some prominent tubercles on the last segment of the body. It 

 then bends itself into a circle ; and having brought the head 

 towards the tail, it stretches out the two hooks ,of the mouth, 

 fixing them into two cavities at the other extremity of the body. 



