Eightieth Thousand.] 
NOTES 
ON 
OX WARBLE FLY, or BOT FLY, 
Hypo derma Bovis , De Geer. 
2 13 
1, Ox Warble Fly ; 2, maggot; 3, chrysalis. 
The Ox Warble Fly, or Bot Fly, is a two-winged fly, upwards 
of lialf-an-incli in length, so banded and marked with differently - 
coloured hair as to be not unlike a Humble Bee. The face is 
yellowish ; the body between the wings yellowish before and black 
behind : and the abdomen whitish at the base, black in the middle, 
and orange at the tip. The head is large ; the wings brown ; and 
the legs black or pitchy, with lighter feet. 
The female is furnished with a long egg-laying tube; but 
whether she inserts her eggs into the hide or lays them on it has 
not been made out with certainty. 
Egg-laying takes place during the summer; it may begin in the 
month of May, but the time varies with the weather, and with the 
cattle being on low land or hill pastures, and other circumstances. 
The egg is oval and white, with a small brownish lump at one end. 
When full-grown the Warble-maggot is the shape figured 
above. 
The mischief may first be found on the flesh side of the hide 
early in the winter. Specimens received from Messrs. Hatton, 
Hereford, on November 13tli, showed the first appearance as small 
swellings bluish in colour, as if half a large shot was under the 
skin, and much inflamed round. The maggots were very minute 
and blood-colour, and lying free (not in a cell) with a fine channel 
down through the hide to where they lay. 
