336 
The Warble-flies of Cattle 
Fortunately it was kept, and on re-examining it in 1892 Riley had no difficulty 
in recognising it as belonging to H. lineatum. 
The other case concerned Glaser himself in the course of his investigations. 
He was experimenting in June 1913 with a female of H. lineatum , which 
oviposited on some hairs which he held behind it. The same insect laid an egg 
on his trousers. The eggs on the hairs hatched in twelve days; that on his 
trousers hatched in eight days and the grub began boring into the skin of 
his leg. In If hrs. it had disappeared leaving a small round red spot. Four 
or five days later it could be felt through the skin, and seemed to be about 
2J mm. long. Early in September its whereabouts was indicated by swellings 
on the hip and the abdomen, and at the end of September Glaser judged, 
from a pain in swallowing, that it was at the lower end of the gullet. Thence 
it rapidly proceeded upwards, and in October he extracted it from his mouth. 
It was a typical oesophageal larva 7*5 mm. in length. 
III. Injuries to Cattle. 
The most obvious injury to cattle inflicted by warble-flies is reflected in 
the hide-markets, badly warbled hides being useless as leather. Every warble 
tumour of the current year means a hole in the leather—usually in the most 
valuable part, near the middle of the back—and though the openings of the 
tumours of previous years close up and no perforation remains, the new tissue 
is of a weaker consistency and a scar is left. To estimate the annual loss from 
this source only it would be necessary to collect statistics from all the hide- 
markets, and the matter would be very complicated, for the hides are graded 
and the percentage of attacked animals differs in each grade, and varies greatly 
in different localities. Miss Ormerod collected the opinions of a large number 
of hide-merchants. A fair sample of the replies she elicited is that received 
from Messrs. Richard Markendale and Co. of Manchester. In 1888 the firm 
handled 250,740 hides of which 83,580 were warbled, and they estimated the 
year’s loss through warbles at £16,716 1 . 
Other ill-effects of warble-fly attack which have long been recognised are 
loss of condition and of milk by “gadding,” and the deterioration of the flesh 
of the back at the time the larvae are entering the hide, an oedematous con¬ 
dition known to butchers as “licked beef,” necessitating the cutting away of 
considerable portions as unfit for human food. Massive infestation may be 
fatal, and it is probable that in a great many cases warble-fly alone was 
responsible for death attributed to various causes. 
The investigations which have led to a fuller knowledge of the life-history 
of the fly have revealed several other lesions for which it is accountable. 
Penetration, for instance, may have serious results, as Hadwen shows in the 
following passage: 
Following the penetration of the larvae down the hair follicles, serum is exuded which 
dries on the surface of the skin, completely covering its pores. The subsequent skin lesions 
1 Twelfth Report, p. 125. 
