THE BREEZE FLY. 
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nal atmosphere, such is not the case with the inhabitant of the 
animal gall. An opening is always preserved in the upper part 
of the swelling, and the tail of the grub is tightly pressed against 
the aperture so as to ensure a constant supply of air. 
In the months of May and June, these swellings maybe found 
in great plenty. They are mostly seen upon young cattle, and 
I as a general rule are situated close to the spine. So common 
indeed are they, that out of a whole farm-stock of cattle I have 
seen almost every cow under the age of four years attacked by 
the Breeze Fly, and counted from two or three to twelve or 
fourteen upon a single animal. It is said that as many as forty 
have been detected upon a single cow, but such an event has 
not come within my own observation. 
The swellings caused by the Breeze Fly are called Wurbles, 
or Wornils, and can be easily detected by passing the hand 
along the back. Strangely enough, the cow does not appear to 
feel any pain from the presence of these large parasites, nor 
does she suffer in condition from them, although it would seem 
that they must keep up a continual drain upon the system. In- 
deed, some experienced persons have thought that, instead of 
being injurious, they are absolutely beneficial. 
When the grub has reached its full development, it pushes 
itself backwards out of the gall, and falls to the ground, into 
which it burrows. Presently, the skin of the pupa becomes 
separated from that of the larva, and the latter dies, and becomes 
the habitation in which the pupa lives. The head portion of the 
skin is so formed that it flattens when dry, and can easily be 
pushed off, like the lid of a box, permitting the perfect fly to 
escape. Even when the insect is still in its pupal condition this 
lid can be removed, so that the pupa can be seen within its 
curious habitation. I may mention here that insects which are 
thus covered while in their pupal state, so as to show no traces 
of the creature within, are said to undergo a ‘ coarctate 9 meta- 
morphosis. Nearly all the diptera are examples of the coarctate 
insects. 
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Before we close the subject of parasites, it will be needful to 
give a brief account of one or two parasitic insects which possess 
