420 INSECTS INJURIOUS TO VEGETATION. 



are rather beneficial than injurious to the animals they infest. 

 His principal work on this subject I have not yet seen. The 

 maggots of the CEstrus bovis, or ox bot-fly, live in large open 

 boils, sometimes called wornils or wurmals, that is, worm-holes, 

 on the backs of cattle. The fly is rather smaller than the horse 

 bot-fly, although it comes from a much larger maggot. The 

 sheep bot-fly ( Cephalemyia ovis) lays its eggs in the nostrils of 

 sheep, and the maggots crawl from thence into the hollows in the 

 bones of the forehead. Deer are also afflicted by bots peculiar 

 to them. Our native hare, or rabbit, as it is commonly called, 

 sometimes has very large bots, which live under the skin of his 

 back. The fly {(Estrus buccdtus) is as big as our largest humble- 

 bee, but is not hairy. It is of a reddish black color ; the face 

 and the sides of the hind-body are covered with a blueish white 

 bloom ; there are many small black dots on the latter, and six or 

 eight on the face. This fly measures seven eighths of an inch, or 

 more in length, and its wings expand about three quarters of an 

 inch. It is rarely seen ; and my only specimen was taken in the 

 month of July, many years ago. 



At the very end of this order is to be placed a remarkable 

 group of insects, which seems to connect the flies with the true 

 ticks ^nd spiders. Some of these insects have wings; but others 

 have neither wings nor poisers. Of the winged kinds there is 

 one (Hippobosca equina) that nestles in the hair of the horse ; 

 others are bird-flies {Omilhomyia), and live in the plumage of al- 

 most all kinds of birds. The wingless kinds have sometimes 

 been called spider-flies, from their shape ; such are sheep-ticks 

 {Mcllophagus ovis), and bat-ticks (Ni/cteribia). These singular 

 creatures are not produced from eggs, in the usual way among 

 insects, but are brought forth in the pupa state, enclosed in the 

 egg-shaped skin of the larva, which is nearly as large as the body 

 of the parent insect. This egg-like body is soft and white at first, 

 but soon becomes hard and brown. It is notched at one end, and 

 out of this notched part the inclosed insect makes its way, when 

 it arrives at maturity. 



The flea {Puhx), may almost be considered as a wingless kind 

 of fly. Its proboscis seems to be intermediate in its formation 

 between that of flies and of bugs ; its antennte are concealed in 



