454 INSECTA. 



TABANUS, Linnaeus, 



Or the Horse-Jlies. These Diptera are very similar to large flies, and well 

 known by the torment they occasion to cattle, by piercing their skin in order 

 to suck their blood. Their body is usually but slightly pilose. Their head is 

 as wide as the thorax, almost hemispherical, and with the exception of a small 

 space, particularly in the males, occupied by two eyes, generally of a golden- 

 green, with purple spots or streaks. Their antennae are about the length of 

 the head, and are composed of three joints, the last of which is the longest, 

 terminates in a point, has neither seta nor stilet at the end, is frequently lunate 

 above its base, and with from three to seven transverse and superficial divi- 

 sions. The proboscis of the greater number is almost membranous, perpen- 

 dicular, of the length of the head or somewhat shorter, almost cylindrical, and 

 terminated by two elongated lips. The two palpi, usually incumbent on it, 

 are thick, pilose, conical, compressed and biarticulated. The sucker inclosed 

 in the proboscis is composed of six small pieces, in the form of lancets, which, 

 by their number and relative situation, correspond to the parts of the mouth 

 in the Coleoptera. The wings are extended horizontally on each side of the 

 body. The alulae almost completely cover the halteres. The abdomen is 

 triangular and depressed. The tarsi are furnished with three pellets. 



These insects begin to appear towards the close of spring, are very common 

 in the woods and pastures, and produce a humming noise when on the wing. 

 They even pursue Man in order to suck his blood. Beasts of burden, having 

 no means of repulsing them, are most exposed to their attacks, and are some- 

 times seen covered with blood from the wounds they inflict. The insect 

 mentioned by Bruce, under the name of Tsaltsalya, which is dreaded even by 

 the lion, may possibly belong to this genus. 



T. bovinus, Lin. An inch long; body brown above, grey beneath; eyes 

 green ; tibia; yellow ; transverse lines and triangular spots of pale yellow on 

 the abdomen ; wings transparent, with russet-brown nervures. 



The larva lives in the ground. It is elongated, cylindrical, and attenuated 

 towards the head, which is armed with two hooks. The nymph is naked, and 

 ascends to the surface of the soil when about to divest itself of its skin, in 

 order to assume the form of a tabanus, and protrudes the half of its body 

 above it 



FAMILY IV. 



NOTACANTHA*. 



THE fourth family of the Diptera, as well as the preceding one, presents 

 antennae of which the third and last joint is divided transversely in the 

 manner of a ring, or which are even composed of rive very distinct joints; but 

 the sucker is formed of only four pieces, and the proboscis, the stem of which 



* Spiny-backed. 



