S. N. SAPRE 111
Veterinary Research Institute, Mukteswar, who
reported: "The diagnosis of tuberculosis
was confirmed and the strain of tubercle
bacillus isolated proved to be of the bovine
type".
A high incidence of tuberculosis was noticed
in cattle on this Farm in 1939-40, though, at
present, it has been considerably reduced by
judicious management and suitable preventive
measures. It is highly probable that this sheep
contracted infection from the bovine stock on
the farm, particularly as the bovine strain of
tubercle bacillus was responsible for the
disease.
SOME OBSERVATIONS ON THE LIFE-HISTORY OF THE DOG TICK
RHIPICEPHALUS SANGUINEUS (LATREILLE) AT MUKTESWAR*
By S. N. SAPRE, B.Sc., G.B.V.C., Research Scholar, Imperial Veterinary Research Institute,
Mukteswar-Kumaun
(Received for publication on 1 December 1943)
THE greater part of the material used in this
work was received from Bombay and Baroda.
The observations were made at Mukteswar (alt.
7,500 ft.).
R. Sanguineus does not appear to adapt it-
self as readily as Boophilus australis to the at-
mospheric conditions existing at Mukteswar,
and specimens of this species could only be
collected in very small numbers from local dogs.
Christophers [1907] made an extensive study
on the life-history of R. sanguineus under Indian
conditions but this was incidental to his work
on the life-cycle of Babesia canis in this species
of tick. It is evidently on this account that his
records are not complete and do not indicate
the temperature at which the specimens were
reared. Nuttall [1914], at Cambridge, worked
out the life-history of this parasite in some de-
tail at 30°C. The present observations on the
non-parasitic stages of the tick were carried
out at 22°C., a temperature slightly lower than
that used by Nuttall, and a relative humidity
of 80 to 90 per cent. In all cases the parasitic
stages of the tick were accomplished on the
dog.
I. Observations relating to oviposition. Two
batches, the first of 29 and the second of 20
gravid females, were kept under observation.
Oviposition commenced three to six days (av.,
four days) after the gravid female left the host,
the process of oviposition lasting 14 to 18 days
(av., 15.6 days). The female survives 2 to 14
days (av., six days) after oviposition ceases and
lays 1485 to 3556 (av., 2140) eggs.
II. The duration of egg stage. The duration
of the egg stage as calculated from the com-
mencement of oviposition to the date of emer-
gence of the first larva was found to be from 25
to 40 days (av., of first batch 31.9 and of the
second batch 31.3 days).
III. The larval stage. More than a 1,000
individuals were observed. These divided into
16 batches were put on the host for feed, the
host being maintained at 1.4 to 11.6°C. The
percentage of engorged larvae recovered on the
fourth day was 62 to 75, on the fifth day 14 to
30 and on the sixth day 1 to 2 only. In one
instance alone engorged larvae were recovered
on the third day, and these were very few. The
non-parasitic period of the larval stage was 24
to 30 days at 22°C.
IV. The nymphal stage.
About 325 indivi-
duals were divided into six batches. The tem-
perature at which the host was maintained was
2.9 to 5.1°C.
The percentage of engorged
nymphs recovered on the fifth day was negli-
gible, that on the sixth was 40 to 54.5, on the
seventh 28 to 45, on the eighth 5 to 9.5 and
on the ninth 1.2 to 6.3. The non-parasitic
period of the nymphal stage varied from 30 to
43 days. Of the 325 nymphs 193 emerged as
females while 129 as males. The sex ratio was
approximately 2 males to 3 females.
V. The adult stage. 49 females and 32 males
in two batches were put on the host to feed.
The host was kept at 11.0 to 14.6°C. Daily re-
coveries of replete females were 9; 22; 6; 6; 4;
1, 1, from the 9th to 15th day.
SUMMARY
R. Sanguineus requires three hosts upon which
to feed. At 22°C. the oviposition lasted for 15
days, the egg stage was 31 days, parasitic
periods for larvae, nymphs and adults were 4,
61 and 10 days and the non-parasitic periods
were 27, 36 and 25 days respectively.
The
parasitic periods of the parasite remained
constant irrespective of the variations in tempe-
*Paper read at the Indian Secience Congress held
at Baroda, January 1942.