DIPTERA. 
59 
opposed to Nematocera,—these and the remaining families of the suborder are 
often grouped together as Orthorrhapha Brachycera. Although the horse-flies 
(Tabanidce ) are often termed gad-flies, the latter name is proved by Anglo-Saxon 
literature to have been originally applied to the (Estrus-growp of the Muscidce. 
Horse-flies are distributed all over the world, and vary but little in outward form, 
usually having large, fat bodies, and being generally of a dull reddish brown 
colour. They are all bloodsuckers, and the mouth-parts—which have been 
described at the commencement of the chapter—attain a high degree of perfection 
as piercing instruments. A common representative of the family in England is 
the so-called clegg (. Hcematopota pluvialis), a greyish insect which has a habit of 
pitching quietly upon the hands or face, and inflicting a sharp prick almost before 
the victim is aware of its presence. Fortunately, however, it is easily killed, for, 
instead of taking flight, it generally stays where it has settled, and allows itself to 
be crushed. A larger, though scarcer British species is the great horse-fly 
(Tctbanus bovinus), the female of which sucks the blood of 
large mammals, such as horses, asses, and cattle. The males 
always frequent flowers; and the larvae in form and habits 
show considerable resemblance to those of the daddy-long¬ 
legs, living in the soil and feeding upon the roots of grasses. 
In this way they spend the winter, reaching maturity in 
May, when they pass into the pupa-stage, the fully-formed 
insect appearing in June. In India these insects are known 
as elephant - flies, for even the thick hide of an elephant 
affords no protection against their sharp needle-like jaws. 
Judging from the account of a resident, horse-flies are a 
terrible plague in Florida. “ Cows, horses, and mules have a wretched time 
in the summer, when they are eaten alive, and come home with the blood running 
down them. When driving, we used to spend all our time killing these soft, 
fat-bodied insects, which die at the least touch—in fact, the commonest kind 
never seem in any case to live more than twenty-four hours, and those which 
come into the houses are always dead the next morning. Their sting is really 
painful. I remember one day, when walking through the flat woods, suddenly 
feeling something like a pin running into my arm, and, on looking down, found it 
to be an extra big horse-fly. The arm was most tender for days after, feeling as 
though badly bruised, and was so much swollen as to make it quite a difficult 
matter drawing any sleeve over it. The ‘ coachman-fly J [doubtless one of the 
family Asilidce] is said to feed on the horse-flies; and will sit through a whole 
drive on the collar, or some other part of the harness, or even on the steed itself, 
in order to pounce on the insects as they settle. The curious thing is that the 
horses seem to know the difference, for directly a horse-fly comes, even if it 
does not sting, they become restless, tossing their heads, and lashing with their 
tails, but the ‘ coachman ’ may rest on any part of them for an}' length of time, 
and never be interfered with, or driven off” 
The flies of the family Asilidce are generally of a somewhat 
slender build, the body being long and parallel-sided, while the legs 
All are provided with a short, powerful, piercing 
GREAT HORSE - FLY, 
SIDE VIEW OF 
(nat. size). 
Robber-Flies, etc. 
and wings are long and strong. 
