WARBLE-FLIES. 225 
their way directly through the skin into the host, instead of 
entering the mouth and thence making their way beneath 
the skin, where they are found in large tumors. Dr. Cooper 
Curtice was the first to draw the attention of entomologists 
to this fact. The life-history of these insects is about like 
this: the eggs are deposited by means of a horny and blunt 
tube, the ovipositor, which ends in a trifid tip, and shows 
by its structure that it could not be used to perforate a 
tough skin; this takes place early in the season, about the 
time when the cattle begin to shed their winter hair, and 
fore-legs, sides, belly and heels are selected for this purpose. 
The eggs are glued to the hairs in a similar manner as was 
described in other bot-flies. From here they are removed by 
the animals, which at this period are continually licking 
themselves to remove the old hairs. In this manner they 
reach the mouth, where the salivarapidly dissolves the hard 
shells of the eggs and the young larve already formed inside 
are liberated. © These young andspiny worms find their way 
down the gullet, and after boring through its walls, wander 
about in the tissues of the host; when they reach theskin they 
form the peculiar swellings known as warbles. Here they 
mature, and boring their way out, drop to the ground into 
which they enter, and where they contract into the dormant 
pupalstage. In about four weeks the winged insects ap- 
pear, to start againa new cycle of life. The larval stage 
lasts from nine to ten months; during this period and es- 
pecially while forcing their way through the tissues of the 
host, they cause inflammations and frequentiy injure the 
animals to such an extent that they lose flesh and become 
very poor. They cause apeculiar greenish and slimy discolor- 
ation and appearance of the flesh of their hosts, which is 
termed by the butchers: ‘‘licked beef;’? when leaving the skin 
they produce holes in it called by tanners, ‘‘warbles.”’ 
These parasites are not common in Minnesota, hence we 
lose but little by their injuries. But a little further south 
they cause immense losses, which a Chicago newspaper, 
that made an investigation of the amount of damages 
caused by this fly in 1889, stated to be $3,337,565. This 
was for the markets of Chicago alone, so that the loss for 
the whole country must have been many times greater. 
