132 Second Report on Economic Zoology. 
Notes on the Sheep Nasal Fly ( (Estrus ovis). 
The following information lias also been sent the Board concerning 
the Sheep Nasal Fly, which is more or less prevalent all over Great 
Britain : — 
“ This fly is sometimes erroneously called the Sheep Gad Fly. 
Bracey Clarke, Steel and others wrote upon it under this name, and 
hence, except by Miss Ormerod, the name has been carried 011 in 
print. The Gad or Breeze Flies are Tabanidre , a perfectly distinct 
family from the CEstridm or Warble Flies. The Gad Flies, Breeze 
Flies or Blimps cause annoyance by ‘ biting ’ animals. Their larvae 
are harmless. In the Warble Flies or GEstvidse it is vice versa. The 
name Sheep Gad Fly is wrong both scientifically and in popular 
parlance. 
“ The adult has also been wrongly described as being ‘ something 
like an overgrown House Fly.’ This statement was made undoubtedly 
as a slip by Kiley thirty-five years ago, and should not be copied, as 
there are flies which are found in connection with sheep that have an 
appearance something like the ‘ House Fly,’ whereas the Sheep ‘ Nasal 
Fly ’ has not. The CEstridse and the Musciclse have nothing in 
common. 
“The description of the Sheep Nasal Fly ( CEstrus ovis) is as 
follows : ‘ Head, pale brown ; thorax, pale brown to ashy grey, 
mottled and spotted with black spot-like tubercles; abdomen, dull 
brownish to slaty grey, sometimes appearing ash-grey with dusky 
spots and with a dull silvery sheen when alive ; legs, pale tawny to 
yellowish brown. The wings are quite colourless and transparent, 
the poisers or halteres almost white and covered by the large basal 
alula or winglet, a flap-like structure at the base of the wings.’ Both 
males and females By about on warm sunny days for the purposes of 
copulation, etc. 
“ On two occasions ‘ maggotty heads ’ have been sent me in which 
the larvae were found in March varying from 4 mm. up to the mature 
size. This clearly points to parthenogenetic reproduction. 
“ The Sheep Nasal Fly certainly deposits its eggs on the nostrils 
of the sheep, for I have on several occasions observed the curved ova 
in and around the nostrils. Brauer, however, was inclined to believe 
that the young were hatched alive, so probably both eggs and young 
are produced. 
“The larvae use their hooks and ventral suckers to aid their 
progress, and also their two anal papillae. Miss Ormerod pointed 
