FURTHER OBSERVATIONS ON THE BIONOMICS OF
                  THE OX WARBLE-FLY (HYPODERMA LINEATUM
                                  DE VILLERS) IN INDIA *

                                                BY

                    B. N. SONI, B.Sc. (PB.), B.Sc. AGRI. (EDIN.)

                Imperial Veterinary Research Institute, Mukteswar

                (Received for publication on 26th January 1939)

                      (With Plate XXXVI and one text-figure)

                                      INTRODUCTION †

THE present author [1938], in a previous article on the bionomics of
Hypoderma lineatum in India, stated that the extent of infestation with this
species in the hill bulls of Garhwal and Kumaun exceeds 50 per cent and
that, apart from punctures in the skin caused by this pest, the affected cattle
suffer from a loss of condition during such time as the larvae are in the sub-
cutaneous tissues of the back. It was also shown that the pest is indigenous
to Mukteswar (Kumaun hills ; altitude 7,000 feet) and that it takes nearly
51 days for the larvae to mature in the backs of cattle under local condi-
tions. In the same article, a reference was made to the continuous occurrence,
for a period of about seven months, of the oesophageal forms of H. lineatum
in the hill bulls at Mukteswar. In the present paper it is proposed to record
a few further observations on the bionomics of the pest which the author
has been able to make at this Institute and also during his surveys in different
parts of the country.

                                SEASONAL OCCURRENCE

A report published in the Veterinary Record [March 1935], under the
heading ' The Warble-fly Campaign in Scotland,' includes a review of Dr.
Stewart MacDougall's experimental work on the control of this pest. In
this review it is suggested that ' dressing for the destruction of larvae must
begin by the third week of March.' This suggestion is based on the ob-
servation that, in Scotland, as illustrated by a seasonal occurrence calendar,
the earliest larvae emerge from their hosts after the second week of March.
If the seasonal occurrence of H. lineatum at Mukteswar were presented by
means of a similar calendar for the round of the year, it would be seen that

* Presented at the Indian Science Congress, held at Lahore in January 1939.
† Since the foregoing observations were made, these larvae have been found to
occur during a continuous period of nearly 11 months in the same breed of cattle
at Mukteswar, the significance of which will be discussed in a separate article.

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