76
Several fairly large varieties of the Muscidæ have been caught on diseased animals, with
their body cavities distended with blood, which, when submitted to microscopical examination,
have been found to contain innumerable Trypanosoma, These flies up to the present have not
been identified and placed in their respective species.
At Poona the Surra animals, especially mules, and at the Surra camp at Karnal the
horses were annoyed night and day by mosquitoes (Culicidæ), which were only kept in abey-
ance by making fires to windward of the animals and allowing the smoke to envelope them.
The following notes with regard to the above mentioned families of Diptera have been
principally abstracted from the works of the Chief British and American authorities on this
branch of science.
The body fluids of flies obtained from every available source were submitted to microscop-
ical examination. During a sojourn in a locality we engaged coolies to supplement our own
staff; consequently fresh supplies of Diptera were brought in several times daily. These were
carefully examined in the fresh state. In different districts one or other species of flies
generally predominates, but they vary also in number and kind according to the season of the
year.
In the plains the commonest variety is the " louse fly " which infest horses, cattle, sheep
and other animals, especially dogs. They belong to the family Hippoboscidæ, "head prone;
neck lying on the prosternum", which is again sub-divided into six genera of which Hippo¬
bosca the first is frequently separated as a sub-order under the term Pupi-para, on account of
the curious method of reproduction.
Walker includes Hippoboscidæ under the Eproboscidæ, Loew and Sacken objected to uniting
under the head of Brachycera, all those families which cannot be referred to the Nemocera,
especially to the union of the Hipposcidæ with the other Brachycera, since both the history
of their development and their internal and external anatomy essentially differ from them.
These authorities include them under a third section, Coriacea, co-ordinate to the Nemocera
and Brachycera and having the same systematic value.
" The species of this family pass their egg-like and larva state in the body of the
mother, and when born are pupæ, or larvæ just ready to assume the pupa state, as is proved
by their size, which nearly equals that of the parent fly, by their slight motion when first
extruded, by spiraculiform points which run down each side of them, and by their changing
into perfect flies. Each female produces a single egg. The proboscis consists of a pair of
hairy coriaceous valves, which include a very slender rigid tube or siphuncle, the instrument
of suction, which is found by the union of two setiform pieces."—(F. Walker.)
According to Dufour and Leuckart quoted by Packard,* the females of this species have
an irregular uterus-like enlargement of the oviduct, which furnishes a milk-like secretion for
the nourishment of the larvæ.
" The flies are parasites living largely upon birds but sometimes upon animals. The
whole body is depressed or flattened, and birds of prey are most usually affected. It is
rare to find a hawk, eagle or owl upon which several specimens of these peculiar flies can-
not be found. They move rapidly, and their first impulse is always to seek shelter when
driven from their original host. A few species are wingless, and among them is the so-called
" sheep tick" Melophagus ovinus, which is usually looked upon as a louse, and resembles one in
the prominent proboscis, the lack of wings, and the strongly developed legs, on which the
claws are very prominent."—(Smith.)
The Forest-fly or Horse-tick (Hippobosa equina) is very abundant in the New Forest,
Hampshire. The description given of it by Walker is as follows :—" Nigra, capite thoraceque
fulvo flavoque varis, alis sordide hyalinis, pedibus fulvis, tibiis posterioribus et femoribus nigro¬
subfasciatis, unguibus nigris. Long. 3—3½ ; alar. 8 lin," According to A. E. Omerod the
Forest-fly must be taken as a type of the division. It causes irritation both by blood-sucking
and by creeping, which it can do backwards, forwards, or sideways with great nimbleness,
on the parts of the animal especially preferred for infestation.
It is thought probable that the Indian cattle-fly belongs to the species Hippobosca¬
maculata (Leach).
Another set of troublesome creatures in India are the Gad-flies or Horse-flies belonging to
the family Tabanidæ. This order, I think, includes the " Bara Dhang" (Hindustani) and Hmet
(Burmese) which are probably varieties of the species T. lineola, the green-head fly, and T.
tropicus.
" They have short, broad heads, enormous eyes, and short, though many jointed, feelers.
The abdomen is oval, a little flattened, and the body is convex and powerful. The mouth
parts are well developed, consisting of a series of five sharp-pointed lancets, so rigid that they
readily pierce the skin and draw blood almost as soon as they touch. These flies appear in the
summer, chiefly abound in woods or the edges of woodlands, and sometimes in low meadows or
* Francis Walker
A. E. Packard .
J. B. Smith
A. E. Omerod .
H. Loew and Oaten
Sacken.
Smith sonian Institu-
tion.
Inseota Britannica " Diptera" .
.
.
Study of Insects (A guide to the)
.
.
Economic Entomology
.
.
Agricultural
Entomology
.
Monographs of the Diptera of North America
Bulletin of the United States National
Museum.
1853, London.
1869, United States, America.
1896,
Ditto.
1884, London.
1862—1873.
Smithsoniau
Institution, Washington.
1886, Washington.