82 BRITISH BLOOD-SUCKING FLIES
Chrysops sepulcralis Fabricius
(Plate 19)
In Ch?ysops sepulcralis the upper surface of the body is deep black in the
male and bronze-black in the female ; the absence of pale hairs along the
posterior borders of the segments of the abdomen in the male give it a much
blacker appearance. In other respects, apart from the approximated eyes in
the male, the two sexes are closely similar and do not show the striking colourdifferences
of caecutiens and relicta. A small but useful further mark of
identity is a prominent angle on the outer margin of the transverse band on
the wing, on the anterior side of the third longitudinal vein and just before its
fork (see pi. igV
Verrall (1909, p. 435) describes the eyes in the male of this species.
British specimens of this species range in size from 6-5 to 9 mm. in the male
sex, and from 7 to 9 mm. in the female. Verrall (1909, p. 436) speaks of C.
sepulcralis as the smallest British species of the genus, but occasionally
females of quadrata are smaller than the average sepulcralis.
The present species is decidedly the rarest of the British Chrysops, although
in certain localities in the south of England it is common enough at the proper
season. Nothing is known of the occurrence of C. sepulcralis in Ireland, and
with the exception of a record from Perthshire the British localities are confined
to Hants and Dorset. \'errall, however (1909, p. 439) wrote : " It is very
probable that the so-called ' black variety ' of C. caecutiens mentioned by Duncan
in 1837 [p. 455] as having occurred in Sutherlandshire and in the south of
Scotland may refer to this species."
On June 30th, 1905, six females of the present species were taken, with
man}' other Tabanidae, in a meadow near Aberfoyle, Perthshire by Mr. W.
Evans (1907, p. 54), and were examined by Verrall, who noted them (1909,
p. 438) as being in some ways different from the typical females of this species.
The collector stated that they were " not uncommon."
The first specimens of C. sepulcralis to be recorded as British were two
males, taken at Studland Heath, Dorset, on August 3rd, 1895, by Capt. Savile
Reid, and in more recent years the species has been captured in large numbers
on Wareham Heath and Morden Heath by Miss E. K. and Mr. N. D. F.
Pearce. The latter authors (1917, p. 257), wrote: " . . . The male sits on
grass stems round the edge of the swamps, and rises for short flights when
approached." The males in this locality were said to be " solitary or sparse,"
but the late Mr. B. D. Burtt found them much more numerous in north-east
Dorset, near the Hampshire border. In a field-note Mr. Burtt says he " saw
any number of male C. sepulcralis flying low, about 12 to 9 inches above the
marsh, or settled half-way up rush and grass stems, where they clung like black
triangles, with eyes glowing. In some the eyes appeared copper-coloured, in
others half green to almost pure jade green. . . ."
The preliminary stages of C. sepulcralis do not appear to have been
observed.
According to Krober (1925, p. 20) the distribution of this species is " north
BRACHYCERA—TABANIDAE 83
and central Europe," and in 1920 (p. 100) the same author gave its occurrence
as Germany, Denmark, Lapland, Sweden, Finland and Russia. It appears to
be absent from the French fauna, which is rather surprising since in England
the principal locality is on the Channel coast. Goffe (1931, p. 59) points out
that the British specimens do not entirely agree with Krober's description of
the species, and Surcouf (1924, pp. 218, 219), while making a similar comment
upon specimens named by Lundbeck, lists the closely related C. maurus
Siebke as British.
Subfamily TABANINAE
Genus HAEMATOPOTA Meigen
DUN-FLIES or CLEGS
The practically universal occurrence of the common Cleg, Hae^^mtopota
phwialis Linn, throughout the British Isles, coupled with the aggressiveness
of the females, renders this species one of the most familiar of British Horseflies.
Three other species of the genus occur in this country. The range of
H. crasstcorms in the British Isles, if less extensive than that of H.pluvialis, is
still wide, but the other two species, H. bigoti and H. italica are of more local
occurrence.
The characteristic shape and colouration of Haejnatopota can be studied
when one of these insects has quietly alighted for the purpose of sucking blood.
The body, in all cases, is narrow and elongate, and the wings in the resting
position meet together at the base and then diverge slightly, sloping somewhat
like the roof of a house. The British species of the genus are sombrely coloured
flies, with dusky bodies only partially relieved by more or less distinct greyish
markings. The wings are suifused with drab-grey (brown in crassicornis) and
in all cases bear the distinctive markings characteristic of the genus. These
consist of pale " rosettes " which always occupy the same relative positions.
The eyes in the living insect are shining coppery-green, bluish green, or brassygreen,
with the upper and lower margins and three horizontal and partly zigzag
lines dark brown.
The early stages oi H. pluvialis have been studied by Cameron (1934), and
notes of some of his conclusions will be found under that species (p. 85). '
Although extremely bloodthirsty and pertinacious in their attacks and
when numerous making their presence felt by both human beings and domestic
animals, the females oi most species of Haematopota are somewhat sluggish
flies, and when actually sucking blood may easily be caught with the fingers
or in a glass tube. Males sometimes hover in the air after the manner of
Syrphidae (Hover-flies), as was observed bv the late Major E. E Austen in
Palestine, near Jaffa on April 29th, 1918. Six males of the species later
described by him as Haejuatopota sewelli were taken at 9.0 a.m. while hovering
poised m the air in front of a tent on the outside of which two females of the
same species were resting.
Cdonel Yerbury, on the other hand, described this motion as " dancing,"
and Verrall (1909, p. 329) writes : " the males sometimes dance in hot sunshine