2
out process involves more young camels than old ones ; of the Surra animals
received in Sohawa last year, 77 per cent. were under 9 years old.
MONSOON TOURS.
8. LAHORE AND LYALLPUR.—A programme for touring in Lahore and
Lyallpur districts in July had been arranged, but in both cases the tours were
abandoned after a few days observation as the rains were later than usual and
it was not easy at the time to find Tabanus even in its well-known haunts.
However a certain amount of information was obtained :—
In Lahore district, Tabanus was found in Rakhs Bengali, Terrah and
Kot Lakhpat.
In Lyallpur district, Tabanus is present along the shaded banks of
canals. Stomoxys is found almost everywhere in a canal colony.
9. BIKANIR STATE.—In August I toured in the State to obtain informa-
tion as to the cause of the outbreaks of Camel-Surra, of which outbreaks a
preliminary investigation had been made in January 1910. A report has been
made to you on the subject but the outbreaks in this State have a general as
well as a local interest and for this reason the circumstances of general interest
are summarised below.
10. Bikanir State occupies a large portion of what is known as the
"Great Indian desert;" outbreaks of Surra have been noticed from time to
time in the Bikanir Camel Corps (Ganga Rissala) and the Shutar Khana,
but the one which has been under investigation occurred in the monsoon
seasons of 1908 and 1909 which were characterised by excessive rainfall. As
a result, in 1910, the Ganga Rissala had, out of a strength of about 500, only
205 survivors, and of these about 130 were suffering from the chronic form
of Surra. It was shown that the camels which had Surra were not (except
in a very few cases) purchased with it, nor had they been beyond the limits
of the State. In one place, the Ghaggar nullah, containing Tabanus enters
the State and in the same portion of the State there is a little irrigation ; but
it was shown that the camels had not been there either at the time of the
outbreak. It was shown that this outbreak occurred when the camels were
grazing in desert country consisting of sandhills where the only water is that
of wells about 80 yards deep and where, even after heavy rain, the water is
quickly absorbed in the sand.
Surra was also found rife in the breeding herds in the State ; these are
continually on the move within the State and the source of infection in them
is impossible to trace, but the fact remains that they spend the Surra season
in similar desert country also.
At a typical desert village I found Surra in a yearling camel also which
had not been outside the village allotment.
11. This sandy desert country appeared the most unlikely place for Tabanus
to breed in. My observations in August were 'made at and around the same
village and the only biting fly present was a Lyperosia (Lyperosia minuta,
Bezzi). Neither Stomoxys nor mosquitoes were found in the desert villages
although both occur in the city of Bikanir and at the Durbar's Garden at
Gajner.
The Lyperosia occurred in swarms on every camel ; they often travel
some distance on the camels and can be found on them at night as well as in
the day-time ; they particularly favour the lower part of the neck, the region
of the hump and the knees. The irritation they cause is intense and the
camels try to dislodge them by violently rubbing against each other ; perhaps
inoculation sometimes occurs in this way, but it is more likely that these small
flies, which are present in such numbers, act as mechanical transmitters of
the disease. It is intended to experiment with the fly next July to definite-
ly ascertain its powers in this direction. Lyperosia appears to have been only
once before suspected on good grounds as a transmitter of trypanosomiasis, i.e.,
amongst cattle in Rhodesia (Montgomery and Kinghorn).
12. That Camel trypanosomiasis may spread in years of heavy rainfall in
the Bikanir desert is a rather startling fact. No such outbreaks have been
seen in the Punjab deserts. Lyperosia may sometimes be found in them, but
as a rule are scanty in number ; the only exception to this I have seen is the