258 INSECTS AFFECTING DOMESTIC ANIMALS. 



become buried out of sight. They seem to attach 

 themselves by their heads, and burrow their way 

 under the skin, completely devouring the soft flesh. 

 Occasionally a few are seen moving from one place 

 to another, but usually they remain fixed at one 

 point. The worms grow steadily in size, and the 

 hole in the flesh becomes larger every day. Some- 

 times the worm makes tunnels, but not to any depth ; 

 they usually stay on the surface. They evidently 

 produce considerable irritation, for the part is always 

 swollen and constantly bleeding. This swollen, gap- 

 ing appearance of the wounds, together with the con- 

 stant discharge of blood, are characteristic of the 

 presence of worms. It seems to require about a 

 week for the worms to become fully grown. At that 

 time they are about five-eighths to six-eighths of an 

 inch long. They then leave the sore and go into the 

 ground, where they pass the pupa state, and hatch 

 out as flies in from nine to twelve days." 



In the accompanying plate (VII) the eggs are 

 shown at a and b, the first representing a single egg, 

 greatly enlarged, and the second a bunch of eggs, 

 also enlarged ; the larva is represented at c, and the 

 puparium at d and e, the former showing the mode 

 of exit of the fly, which is represented at / and g. 



The egg of this insect is is inch long, whitish, and 

 cylindrical, with a longitudinal ridge on one side. 

 The full-grown larva is \ inch long by £ inch in 

 diameter. It is a whitish, footless grub, with trans- 

 verse rows of stiff, black bristles at each articulation. 



