Blood-Sucking Flies other than Mosquitoes 257 
Flies, ’ mentions Portschinsky as stating that in the Gdov District of the St. 
Petersburg Government, in Russia, cow-flies are such a pest to man that agri- 
cultural operations have to be carried on at night, while in parcs of Siberia 
settlers have to abandon infested zones. 
One of our smaller cow-flies, Pabanus trilineatus is a frequent visitor in houses, 
blundering in and alighting on the window-panes. It is the commonest cow- 
fly onthe coast. Itis grey, and has three whitish lines on the abdomen. It can- 
not be described as blood-thirsty as regards man. On the other hand, cows, 
horses and donkeys suffer at times severely from its attack. Some months ago 
on the Craig public road I observed two donkeys, presumably mother and 
young, badly worried by scores of this fly. The colt wasthe greater sufferer. 
principally because it never went out of the district, being too young to be used 
in draft, and because lameness in a leg restricted its activity. I was then at 
work on the insects of that district, which I visited two or three times a week for 
several weeks, and on nearly every visit I passed the colt, which was always 
crowded with flies. It was plainly so tired and disgusted at contending with 
them that it had given way to despair, and now hardly troubled itself about 
them, but generally allowed them to exercise their blood-thirsty proclivities at 
their own sweet will. The flies attacked chiefly the central line of the face, the 
back of the ears, the shoulders and the lower parts of the feet—just those parts 
of their bodies that could not well be reached by the tail. The colt was 
quite sore on the face, ears and thighs, while from both animals blood freely 
trickled at several places. 
A cow-fly we have to dread is Tabanus pellucidus, large, nearly an inch long, 
thorax grey, abdomen chocolate brown with small grey spots on centre and 
sides, wings smoky. It is abundant in the interior and fairly plentiful on the 
coast. It is very blood-thirsty, is fond of attacking one’s back and shoulders, 
and will follow us for considerable distances. It is very persistent in attack, 
returning again and again if driven off. Fortunately for the attacked, it 
betrays its approach by a loud hum, and with a little care and watchfulness 
one easily gives1 its quietus by means of a slap or the killing-bottle. Its prick- 
ing is intensely sharp, as know from personal experience. 
More blood-thirsty yet, more persistent in attack, and more successful too, 
as it is almost silent in its approach, is a species of Chrysops, very common in 
woody and bushy places, such as the Botanic Gardens and the foreshore where 
the courida is dense. It is the exception if I go into the bushy parts‘of the 
Botanic Gardens, and am not dogged by this Chrysops. In fact, its low soft 
hum is generally the first insect sound to greet my ear. This is a brown fly, 
with four grey lines on the thorax, and three lines of grey spots on the abdomen. 
The wings are brown on the upper margin and across the middle, while the 
antenne are long, brown, and taper to a point, which is blackish. It is fond of 
attacking the face and neck, quietly alighting on one ’s hat and then c awling 
cautiously down to one’s face or neck to indulge in a drink of blood. I never 
let it get so far as to drive its proboscis into me, for as soon as its hum ceases I 
know it is on my hat or shoulder, whence it has then got to take to flight in a 
great hurry, or pay the death penalty. Once only in the Ogle courida I allowed 
