592 Insects. 
THE HOUSE FLY. (Musca domestica.) 
This insect lays its eggs in sinks, dunghills, or any other 
place where there is decaying vegetable matter tolerably 
moist. The larvae, or maggots, are thick and fleshy, with- 
out legs, but having the mouth furnished with hooks, by 
means of which they drag themselves along when they 
wish to move. They go into the pupa state without 
throwing oif the skin of the maggot ; and when the per- 
fect insect appears, it forces off a kind of cap from one 
end of the pupa case, in order to make its escape. The 
Blue Bottle flies (Musca eryihrocephala and Vomitoria) are 
only too well known from their habit of depositing their 
eggs upon our meat in summer. In the Flesh fly (Musca 
or Sarcophaga carnaria) and some allied species, the eggs 
are hatched within the body of the parent, which thus 
deposits living larvae upon the decomposing animal 
matter that constitutes their food. These flies are so 
prolific and their larvae so voracious that Linnaeus says 
the progeny of them would devour a horse as quickly as 
a lion could do it. 
THE GNAT. (Culex pipiens.) 
This is an insect which deserves the observation of the 
naturalist, not only for the very curious conformation of 
its proboscis (which so quickly and powerfully pene- 
trates into our skin, and through which it sucks our 
blood into its body), but also for the several metamor- 
phoses it undergoes before it arrives at its winged state. 
The Gnat deposits its eggs upon the surface of stagnant 
water, and sets them upright one against another, in the 
form of a small boat : after floating upon the water for 
several days, as soon as the time of hatching arrives the 
