100 
WARBLE FLY. 
\ 
observed, as they show that the passage could not be formed by 
ulceration, which would not have given clean smooth walls to 
the hole. 
The maggots in this state of warble differed in size; the smallest 
I measured was about half an inch long, and nearly worm-like in 
shape; rounded at the mouth-end, bluntly pointed at the tail, white, 
transparent, and marked across what may be called its back with 
Fig. 2. 
Fig. 2.—Young maggots, much magnified. Fig. 3.—Mouth-forks of very 
young maggot, much magnified. 
sixteen short bands of very minute black or dark grey prickles, placed, 
for the most part, in alternate very narrow and broader stripes. There 
was some variety in the shape of the maggots, according to whether 
they were alive and distended with fluid, or other circumstances ; but 
those I had at this stage were worm-like or spindle-shaped, and in the 
youngest condition the maggot was furnished with a pair of strong 
mouth-forks (fig. 3), which are a most important item in its structure, 
and, as far as I am aware, have not previously been noticed in the 
young maggot of this species of Hypoderma or Warble Fly. 
The apparatus may be described as consisting of a pair of 
crescent-shaped forks, placed nearly side by side, at the extremity of 
processes somewhat bent apart at the ends by which they are attached 
to the crescents, and attached by the other ends to the membranes or 
tissues forming the gullet or internal sac of the maggot (see fig. 3, 
showing, at 1 and 3, the crescent-shaped forks in slightly different 
positions, and at 2, the apparatus viewed sideways, so as to show the 
curved ends of the processes). The material is chitinous or horny, 
and the colour yellowish brown, and, though excessively minute, the 
hook forms a very serviceable cutting or dragging implement. 
The possession of this apparatus by the maggot in this early stage 
is a great confirmation of the belief that the creature gets down to the 
subcutaneous tissues of the hide simply by cutting its way forward. 
We appear here to have both cause and effect, for we find as a regular 
thing that there is a minute track down to the embryo warble beneath 
the hide, which said track has the appearance of having been cut 
or gnawed; and in the exceedingly young and still worm-shaped 
