(;38 INSPXTS AT HOME. 



enemy, rubbing their noses against the ground, shaking their 

 lieads, and rusliing about in all directions. Their exertions are, 

 however, useless. Sooner or later, the fly succeeds in depositing 

 her eggs just inside the nostril, and there leaves them. They 

 are soon hatched, and then the young larva, which is furnished 

 with hooked appendages to its head, crawls up the nostril, and 

 fixes itself in the frontal sinus. Its life then much resembles 

 that of the other insects of the family. 



Antelopes are known to be specially subject to the attacks of 

 the Gad Fly, and all African hunters say that the head of the 

 gnu is never found to be without at least one Gad P'ly grub in 

 the frontal sinus. 



We now come to the last great division of the Diptera, the 

 Thoracocephala, or those insects whose heads are sunk in the 

 thorax. Like the preceding insects, they are all parasitic, but 

 they differ in many points from them. In the first place, 

 there is the position of the head, to which reference has just 

 been made, and besides, the antennae are differently arranged, 

 and the mode of transformation is different. In consequence 

 of these peculiarities, it has been thought by several eminent 

 entomologists that these insects ought not to be ranked with 

 the Diptera, but to be constituted into a separate order, to 

 which the name of Homaloptera was given. If has now, how- 

 ever, been decided that they really are Diptera, though they 

 form a very divergent branch of that great order. 



They are divided into two families, the first of which is 

 named Hippoboscidse. This term is composed of two Greek 

 words, the former signifying a horse, and the latter, to feed 

 upon. How thoroughly appropriate is the word, anyone can 

 tell who has driven or ridden a horse when the Flies are 

 about. They are very active on foot, and can run sideways aa 

 fast as they can forward, burying themselves among the hair 

 or feathers of the creature which they attack. In some of the 

 insects the wings are entirely wanting, as is the case with the 

 very common Sheep-Tick [Melophagus ovinus). I need 

 scarcely say that the name is entirely a wrong one, inasmuch 

 as the Sheep-tick is an insect, and the true ticks belong to 

 quite a different class of beings. This, being very plentiful, 

 ■will serve as an excellent example of the Hippoboscidse. It 



