6 
WARBLE FLY. 
to be of a pear- or club-shape, white, and partially transparent, and 
marked across what may be called the back with sixteen short bands 
of very minute black or dark grey prickles, placed, for the most part, 
in alternate very narrow and broader stripes (see fig. 3, p. 5). The 
young maggot possesses (apparently as an instrument for tearing out 
food) a pair of crescent-shaped forks or diggers (see fig. 4, p. 5). These 
are of such excessive minuteness that they are only to be found with 
difficulty, and I have not as yet found them in any but very young 
maggots. 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. The material 
is cliitinous or horny, and the possession by the embryo (still worm- 
like) maggot of this apparatus for cutting or tearing is of considerable 
interest in connection with the first minute track (which shows as 
being cut or torn) down through the hide to the embryo maggot lying 
below. 
The power of pressure possessed by the maggots at this period of 
their life is enormous, from their capacity of inflating themselves with 
fluid until they are so hard that it is scarcely possible to compress 
them with the fingers, and likewise from their having (apparently) no 
power of discharging any of their contents. Thus they form living 
and growing plugs, quite capable of pressing back the tissues from 
around them, or from before the small hard tip; but not subject (so 
long as they continue inflated) to being themselves compressed. I 
had opportunities of watching this process of inflation both in the 
worm-shaped maggots and when they were slightly more advanced in 
growth to a club or lengthened pear-shape. On placing them in fluid 
suitable for absorption (as in glycerine and water, in which they would 
live for as long as eighty hours, or until the spiracles sank completely 
beneath the surface) they became hard and shiny, and with little trace 
of the segments which are so clearly marked when the maggots are 
fully developed; in fact, they were almost of a glassy smoothness, 
save for the short bands of minute prickles placed along a portion of 
the back. 
This power of inflation of the maggot appears to be an important 
agent in forming what is presently the open passage or warble-hole 
down to the cell beneath. The various stages of maggot life consist 
of the passage of the worm-like larva to the under side of the hide, 
where, at this stage, in the small inflamed patches or swellings (see 
p. 3) it lies free, that is to say, not enclosed in a cell or thickened 
tissue, merely in a small bloody sore, in which by the colour of its 
contents it may be seen to be feeding on the bloody matter. This 
