GAD- OR BREEZE-FLIES. 167 
commonly found in the neighborhood of marshes, and our 
prairies with their numerous low andswampy places abound 
in them. Woods and pastures are also frequently visited by 
them. This is accounted for by the fact that the early 
stages of this insect are passed below the ground, in wet 
soil, and even in water. Their eggs are brown or black, 
spindle-shaped, and are deposited in groups upon aquatic 
plants and stems of grass. When the sun is very hot in sum- 
mer these insects are most active, and thousands of them fly 
about, and frequently torment the larger animals to such 
an extent as to make them perfectly wild and frantic. The 
moose and deer, attacked by such tormenters, lose all fear 
of man and plunge into rivers and lakes to escape their at- 
tacks; they soon _ be- 
come very poor, as 
they have no rest to 
feed excepting at night. 
Even the most rapid 
animalscan not escape 
these swift tormenters, 
which descend upon 
them and, choosing the 
most tender portions 
Of ate mesktl, avai 
their powerful probos- 
Fig. 137.—Mouth-parts of Tabanus. Greatly : : : 
enlarged. Original. cis (fig. 137) in it and 

do not withdraw it 
until satished with blood. A slight swelling, which soon 
disappears, shows where the skin is perforated. Their flight 
is so rapid that they can not only follow an express train 
but can make excursions into the country at the same time. 
This is frequently seen when one of them settles upon the 
window of a fast train in motion, and after awhile darts off 
some distance soon to return to its resting-place. It is be- 
lieved that such flies are agents in transmitting virulent dis- 
eases, when they leave an animal affected with one of them 
and introduce their proboscis into the skin of a healthy one. 
We have a large number of such insects in Minnesota, 
but all possess a very similar life-history, at least as far as 
