MOULTS OF THE MAGGOT. 
9 
its growth that the spiracles were developed to their angularly kidney¬ 
shaped form, and the maggot assumed the compressed oval shape in 
which it is best known. It was still white, but opaque, and with the 
segments well-marked; and the early part of its work being done, and 
the warble-passage open, it has no occasion noiv to bore its way, and ceases 
to be furnished with a form fitted for perforation. 
Other alterations of a very practical bearing also take place at this 
time, or follow on this most important of the moults. The skin of 
Fig. 9. 
Fig. 10. 
Fig. 11. 
Fig. 9. —Muscles within skin of maggot, much magnified. Fig. 10 —Prickles of 
maggots, much magnified. Fig. 11. —Full-grown maggot, magnified. 
the maggot becomes furnished within with a powerful coat of muscles, 
extending over it like basket-work, which give it a power of contraction 
and expansion. Externally in this stage the skin of the maggot is 
furnished with a much larger amount of prickles arranged in more 
numerous bands, than are noticeable in the previous stages. The 
prickles are now strong enough to cause an unpleasant sensation 
when the maggot crosses the hand, and to play an important part in 
its locomotive powers in its cell, and in the effect on the tissues caused 
thereby. The visceral contents are now thick, and obviously formed 
of the filthy matter which is caused by the perpetual irritation of the 
suction of the mouth-end of the maggofc'at the bottom of the sac. It 
is also now furnished with a small curved caudal aperture, placed 
nearly between the spiracles (see fig. 8, p. 8) from which some slight 
amount of discharge of contents can take place. 
Fig. 11 shows the maggot about four times the natural size, in its 
fully developed state, with the tips of the pair of spiracles indicated in 
the centre of the tail-end. It is, as is well-known, when full-fed, and 
for much of its previous life, of a bluntly oval somewhat compressed 
shape, of various shades of colour, from whitish to deep grey or 
brownish, and marked with cross-bands, which, under the magnifier, 
are seen to be formed (as figured above) of minute prickles. 
