Reports of the Honorary Consulting Entomologist. 703 
From careful study of the history of the ox bot-fly, or warble- 
fly — the CEstrus (Hgpodermus) hovis — joined to the recent 
experiments made by JMr. Stratton, there does not appear to be 
any doubt that from the time that the first ulceration takes 
place, by which an opening is formed into the coming swelling, 
that the maggot within can be rapidly and surely killed, with 
little trouble or expense. 
In Mr. Stratton's recent experiments, the simple application 
of a little mercurial ointment, placed on the orifice, killed the 
maggot. A little arsenite of copper (commonly known as Paris 
Green, or Scheele's Green) likewise killed the maggot, but 
caused some slight inflammation ; and a little pitch served the 
same purpose, excepting in one instance, where the maggot was 
not quite certainly dead on examination. The mercurial oint- 
ment acted the best, as it not only killed the maggot, but rapid 
decomposition followed. 
These applications were tried when the warble was in the 
advanced stage it attains in spring, but would, as far as we see, 
act equally well as early as about October of the previous year. 
The warble-fly deposits her egg during the summer, and the 
maggot, which takes its position within the lower layers of the 
hides, is at first quite smooth in its skin, and lies without 
causing noticeable harm, and also, as far as is known, without 
communication with the air ; but afterwards (at its first moult) 
it gains a skin set with patches of rainute prickles, by means of 
which irritation, and then ulceration, is set up, and the opening 
formed. 
This takes place towards autumn, and by passing the hand 
along the back and loins of the cattle, the warble may be 
detected as soon as it is as large as a nut ; and early attention 
would be of great service to the cattle, and further is of great 
importance relatively to saving loss on the warbled hide. 
At first the cavity is very small, and whilst it is still only a 
small sore, healing will readily take place on removal of the 
cause of irritation ; but after some months, when the maggot has 
nearly attained its full size, it has been found, by the observa- 
tions of German anatomists, that a growth which much re- 
sembles that of the various layers of true skin has formed over 
the inner surface of this maggot-inhabited hole in the hide ; 
consequently, when the maggot has left it, although the cell 
may draw together, there appears good reason why the already 
healed surfaces should not unite. 
Other points in the habits of the fly may be brought to bear 
on reducing the amount of attack, and when it is advanced, such 
methods of action as pricking the grub, or squeezing it from the 
warble, will destroy it; but the measures needed are those 
