THE STRAIGHT-SEAMED FLIES 3021 



Although related to the gnats and midges by the nature of the slit 

 ^ s j. through which the pupa makes its escape from the larval skin, and 

 consequently referred to the section Orthorrhapha, the flies of this 

 family approach those of the second section in the shortness of their antennae, and 

 since all the Diptera with short antennae were formerly termed the Brachycera, as 

 opposed to Nematocera, these and the remaining families of the suborder are 

 often grouped together as Orthorrhapha Brachycera. Although the horseflies 

 ( Tabanidce] are often termed gadflies, the latter name is proved by Anglo-Saxon 

 literature to have been originally applied to the CEstrus group of the Muscida. 

 Horseflies 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 

 color. 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 (Htzmatopota pluvialis), a grayish 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 horsefly 

 ( Tabanus 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 or 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 GREAT HORSEFLY WITH 



affords no protection against their sharp needle-like jaws. SIDE VIEW OF HEAD> 



* r . (Natural size.) 



Judging from the account of a resident, horseflies 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 horsefly. 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' [doubtless one of the 

 family Asilidce] is said to feed on the horseflies; 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 horsefly comes, even if it 



