32 BRITISH BLOOD-SUCKING FLIES
22. Smaller (wing barely I mm.), wing-markings very faint chto;ptenis Mg.
Larger (wing about 1-4 mm.), wing-markings less faint obsoletus Mg.
23. No spot in cubital fork 24
A small separate dark spot in cubital fork 25
24. Smaller (wing about 1-5 mm.), thorax unmarked impunctatiis Goet.
Larger (wing about 2 mm.), thorax with markings delta sp. n.
25. Two dark marks in median fork, one near base halophilus Kieft.
Only one dark mark in median fork, towards tip pulicaris L.
Culicoides stigma Meigen
(Fig. 3)
This is one of the most easily recognised species of Culicoides, having the
body mainly sooty-black and the wings milky-white, with a single deep black
spot in the middle of the front margin. The thorax exhibits no definite pattern,
though it has some ill-defined greyish areas on the shoulders and posteriorly ;
the legs are blackish and the halteres yellow.
C. stigma is one of the largest species of the genus, having an average
wing-length of 2-5 mm.
NEMATOCERA—CERATOPOGONIDAE 33
FIG. 1—Culicoides stigma Mg. Wing of
In the south of England C. stigma is a decidedly uncommon insect ; the
very small number of specimens in the British Museum are from the counties of
Herts., Middlesex, Devon and Notts. It may be commoner in the north as
Mr. H. Britten has taken numerous examples in and around Manchester.
Dates of capture are mostly in May and June, with one record in September.
Some specimens were taken biting at sunset, the bite being painful. Some
of the specimens from Manchester were reared from larvae found among
floating green algae at the edge of a small pond.
Culicoides parroti Kieffer
This strikingly distinct species might be confused with C. stigma on account
of its milk-white wings with a single deep black spot occupying the second
radial cell, but a glance under a lens is sufficient to separate the two. The
thorax of C. parroti is mainly light greyish, with numerous small blackish dots
on the shoulders and three rather irregular blackish stripes, which tend to
fuse, the lateral stripes being abbreviated in front ; the halteres are mainly
blackish, with only the tip yellowish.
C. parroti is one of the rarest of our British Culicoides ; the first British
specimens were obtained by H. Britten near Manchester in May 1922, and
it has also been recorded from Herefordshire by J. S. Steward.
The specimens from Manchester were reared from larvae found among
floating green algae at the edge of a small pond, in company with larvae of
C. stigma ; those from Herefordshire were taken feeding on a horse.
Outside Britain C. parroti has been recorded from Algeria and Turkey ;
the original specimens were taken feeding on a donkey.
Culicoides nubeculosus Meigen
(Fig. 4 and Plate i)
The grey pattern on the wings, with a conspicuous black area covering the
radial cells and a second darker area beyond this, together with the stippling of
FIG. 4.—Culicoides nubeculosus Mg. Wing of
dark brown dots on the thorax, are characters which will sufficiently distinguish
this species from all others of the genus in Britain except the very similar C.
riethi. For the separation of these two a closer inspection is necessary, but
obvious diagnostic features are to be found in the thorax and wings. In C.
nubeculosus the dark dots on the mesonotum are rather larger and tend to run
together ; the scutellum is j^ellowish at the sides, but largely dark in the middle,
the dark area including a yellowish or greyish spot in the middle of the posterior
margin ; the wings are rather densely hairy over most of the surface, some hairs
being present in the area below the radial cells. The dark markings of the
wings are usually rather diffuse, as shown in fig. 4, but may be more sharply
defined (as in a series of specimens from Wareham Heath) ; in the latter case
It IS difficult to distinguish between C. nubecjdosus and C. puncticollis.
C. nubeculosus is one of the largest species of the genus, having an average
wing-length in the female sex of 2-5 mm.
In Britain C. nubeculosus is widely distributed, but decidedly local. It is
sometimes abundant about farms, having been taken in such situations in
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