than are noticeable in the previous stages. The prickles are 
now strong enough to cause an unpleasant sensation when the 
mao-got crosses the hand, and to play an important part in its 
locomotive powers in its cell, and in the effect of the tissues 
caused thereby. The visceral contents are now thick, and 
obviously formed of the filthy matter in the cell. It is also 
now furnished with a small curved caudal aperture, placed 
nearly between the spiracles, from which some slight amount 
of discharge of contents can take place. As the maggot 
crrows the lining of the cell (fig. 9) increases in thickness, 
until it becomes well defined as a tough wall round the 
perforation, continuous with the upper part of the cell. When 
the creature has gained the condition named above, it under¬ 
goes no further great change until it turns to the chrysalis 
state. The spiracles become less radiated and darker, the 
Fig. 12.—Maggot of Ox Warble Fly, 
drawn from life, life size. 
I3 .—Chrysalis of Ox Warble Fly, side view, 
and showing contained fly. 
mao-a-ot also becomes darker, but the main points of its life 
now are to form, at the expense of the animal in which it 
lives, the material from which the fly will presently be 
developed, to start (unless means have been taken to pre¬ 
vent it) the next season’s attack on the herd. 
On April 21st, I pressed two maggots out of cows, and 
two days afterwards seven more, with very little force, five of 
them from cows, and the other two from yearling heifers. 
They were from f inch to i inch long, from f inch to a little 
more than ^ inch in width, and were slightly less m depth 
They were of an oval shape, and blunter at the mouth end 
than the other, and varied in colour from pale yellow to black. 
They kept up a regular contraction and expansion as t ie) 
lay on the table, and moved their mouth end from side to 
side in all directions. The breathing spiiacles at the^ ho e o 
the warble were noticeable as two black spots. Their bodies 
had from nine to ten rings going right round them. The skin 
