thorax, resembling dusty streaks. The abdomen is white or 
yellowish at the base, black in the middle, and orange at the 
end. The legs are black, with red feet; the wings of a 
brownish colour, and unspotted, and with two large alulets. 
The body between the wings is yellowish before and black 
behind. The female is furnished with a long egg-laying tube, 
or ovipositor, which is described by Reaumur as consisting of 
four tubes, one within the other, and the insect is capable of 
pushing them out like a pocket telescope. The outer tube is 
hard and shelly, and the inner one is terminated by five sharp 
points, of which three are hooked, and longer than the others. 
The fly is without any sucker ; the antennae are very short, 
proboscis and palpi obsolete, thorax smooth, and the body in 
the female very long. It is found from Norway and Sweden 
to the South of Europe, also in Asia, Africa, South America, 
&c., in fact in almost all parts of the world. 
In Norfolk and Suffolk these flies are reckoned useful by 
the ignorant, and as the GEstrus selects the healthiest 
cattle, the farmers prefer those cows which have on their 
backs three or four lumps or “ bots ” produced by this insect. 
The fly seldom appears until June. 
The cattle have a great dread of this fly. At the first 
sound of its buzz they at once gallop off in extreme terror, 
with tails stretched out and necks extended, endeavouring to 
get out of reach of their winged assailant. From the appear¬ 
ance of temporary madness in oxen when pursued by this 
insect, the Greeks applied the term “ oestrus ” to any sudden 
fit of fury, or sudden impulse in man. 
In places where ploughing with oxen is practised, the 
attack of this insect may be dangerous, as they at once 
become perfectly unmanageable, and, whether in harness or 
yoked to the plough, will run directly forward. 
The female fly is observed to be very expeditious in 
oviposition—not more than a few seconds. She fastens on 
the back of an ox or cow, leaving only one egg in a place, 
with an interval of one or two inches between each insertion. 
While she is performing the operation the animal attempts to 
lash her off, as it does other flies, with its tail. 
Bracy Clark, a great authority on Bot Flies, and other 
writers, state that when cattle are attacked by the Warble 
