228 DIPTERA OR TRUE FLIES. 



this species may briefly be summed up as follows : The 

 flies lay their eggs in putrid and decaying substances, but 

 especially in horse - manure ; they deposit their eggs in 

 batches, each fly producing from seventy to one hundred and 

 fifty ova, and these often hatch in a day ; the larvse are 

 dirty - white footless grubs, which cast their skin twice, and 

 then in a week they become full fed, stop feeding, and the 

 skin hardens into a brown puparium case. This stage, still 

 in the dung-heaps, may last a week or several weeks, depend- 

 ing on the weather. Larvae, pupa, and flies may be found 

 all the year round. The house-fly lives by sucking up its 

 food. They annoy us and our animals to feed off the sweat. 

 The spaces round the eyes of animals are favourite places ; they 

 sometimes cause much annoyance to horses. N'umerous other 

 species of Muscidas and Anthomyidse are called house-iiies, 

 the technical differences of which we cannot enter into. The 

 house-fly is destroyed wholesale by a fungus, Empuga musca, 

 the spores of which germinate in the body, and the mycelia grow 

 out, killing the fly and fixing it, as we so often see, to the 

 window-panes. 



Another noxious fly sometimes found in houses, stables, 

 cowsheds, and pigstyes is called the Biting Fly (Stomoxys 

 calcitrans), which sucks the blood out of animals, and even 

 attacks man : it is one of the true Muscidse. It is provided 

 with a sharp piercing proboscis (fig. 115) with which it pene- 

 trates the skin of its victim. 



Ticks, Forest Flies, &c. (Eproboscidea). 



The Eproboscidea are the Sheep-ticks, Forest or -Horse Flies, 

 and Bird Flies. They are generally called Pupipara, and 

 present many peculiarities, which can only briefly be referred 

 to here. Some resemble spiders in appearance, but the number 

 of their legs soon identifies them. They are all parasitic in 

 habits, living upon warm-blooded animals. Some are quite 



