themselves of the plague ; and the more liigli-bred and high-spirited 
the horse, and sensitive to foreign touch on the skin, the greater the 
annoyance and consequent risks. 
When on the wing taking its short flights, the fly appears of a 
brilliant shining black colour, and of shape and size figured at 
heading (life-size and magnified) ; but when at rest its single pair of 
wings are folded down along the back. When the abdomen of the 
female is swelled up by food, or by the presence of its single maggot 
before deposit, it looks not unlike a spider, whence its name of Spider 
Fly; when empty the flattened appearance gives the name of Flat Fly. 
The flies are tough and bristly or hairy; when seen magnified the 
general colour is of a horny, shining dark brown, lighter along the 
middle of the abdomen, and with various small tawny yellow markings 
on the fore body between the wings, and a large yellow spot or ring 
on each side in front just behind the head. Head and eyes shining 
black or brown ; face yellow, with a dark stripe up the middle. Mouth- 
parts are very peculiar, but for practical purposes it is enough to 
mention they include setae which can be driven deep into the attacked 
animal. Legs tawny, variously striped and ringed with darker tints, 
and somewhat bristly; and the strong curved claws, of which there 
are two on each foot (each claw bearing a side tooth), are also dark 
coloured or black. The two wings not very transparent, and with 
strong dark veins towards the foremost part. Length of body about a 
quarter to a third of an inch, of spread of wings about two-thirds of 
an inch. 
The very remarkable part in the history of this fly is that, like 
others of the genus Hippobosca, it only lives actively in the fly-state. 
The flies do not lay eggs , but the larvte or maggots hatch, and are 
nourished up to their full growth within the abdomen of the females ; 
one maggot only inside each fly. They then change to the pupal 
state, and are deposited in this state (or ready quite immediately to 
turn to it) in the shape of white roundish bodies often mistaken for 
eggs, and very like them, excepting that they are notched at one end. 
These rapidly change from white to a dark brown colour, somewhat 
resembling a laburnum-seed, and within this puparium the fly forms, 
and in due time escapes by cracking off the notched end of its hard 
covering. 
According to what may be called regular record, the fly feeds by 
blood-sucking, and its piercers, or setce, which resemble those of the 
gnat in their great length, point to this being the case ; nevertheless 
locally , and by those well used to observation, it has been told me so 
often that they feed on the moisture amongst the hair, that some 
further investigation as to how far this occurs would be useful. 
The following note is from an experienced local observer :—“ They 
do not seem to bite or sting, but evidently find nourishment in the 
perspiration given off by cattle during the period of their activity, 
i* e., the summer months. Well-groomed horses therefore afford least 
attraction for these flies.”—(D. D. G.) 
The point of the direct pain caused by the attack not being the 
chief cause of annoyance is thus noted in a good continental observa¬ 
tion :—“ They feed by blood-sucking ; still it is less by their sting (or 
puncture) than by their crab-like movements on the skin that the 
horses are made restive.”—(E. L. T.) 
