VII SARCOPHAGIDAE— MUSCIDAE 5 I I 



Kiinckel has recently observed that in Algeria several species 

 of this genus attack Locusts and destroy large quantities by 

 depositing living larvae in the Orthoptera. In North America 

 the Army-worm is decimated by species of SarcojjJiaga. 



Many of these Insects, when food is scarce, eat their own 

 species with eagerness, and it seems probable that this habit is 

 beneficial to the species. The parent-fly in such cases usually 

 deposits more eggs than there is food for, thus ensuring that 

 every portion of the food will be rapidly consumed, after which 

 the partially-grown larvae complete their development by the 

 aid of cannibalism. It is thus ensured that the food will raise 

 up as many individuals as possible. 



Fam. 38. Muscidae. — Bristle of antennae feathered. This 

 family contains many of the most abundant flies, including the 

 House-fly, Blue-bottles or Blow-flies, Green -bottles, and other 

 forms which, though very common, are perhaps not dis- 

 criminated from one another by those who are not entomologists. 

 The larvae live on carrion and decaying or excrementitious 

 matters. The common House-fly, Musca domcstica, runs through 

 its life-history in a very short time. It lays about 150 very small 

 eggs on dung or any kind of soft damp filth ; the larvae hatch 

 in a day or two and feed on the refuse ; they may be full-grown 

 in five or six days, and, then pupating, may in another week emerge 

 as perfect flies. Hence it is no wonder that they increase to 

 enormous numbers in favourable climates. They are thought to 

 pass the winter chiefly in the pupal state. The House-fly is 

 now very widely distributed over the world ; it sometimes occurs 

 in large numbers away from the dwellings of man. Of Blow- 

 flies there are two common species in this country, Calliphora 

 erythrocephala and C. vomitoria. The Green-bottle flies, of which 

 there are several species, belonging to the genus Lmilia, have the 

 same habits as Blow-flies, though they do not commonly enter 

 houses. The larvae are said to be indistinguishable from those of 

 Callipliora. 



The larvae of Eumyiid Muscidae are, when first hatched, 

 metapneustic, but subsequently an anterior pair of stigmata 

 appears, so that the larva becomes amphipneustic. They 

 usually go through three stages, distinguished by the condition 

 of the posterior stigmata. In the early instar these have a 

 single heart-shaped fissure, in the second stage two fissures exist, 



