46 B R I T I S H BLOOD-SUCKING FLIES
C. obsoletus is abundant in most parts of Britain, extending as far north as
Sutherland, though perhaps more numerous in the south. In bloodthirstiness
it is second only to C. inipimctatus, and everyone living in the country must be
only too familiar with its activities on warm summer evenings in the gardens.
Though most abundant in June, C. obsoletus may be found throughout the
summer, and in a damp autumn is sometimes very numerous again in September
and October, a fact which suggests that it has normally at least two broods in
the year.
In spite of its abundance the life-history of C. obsoletus is still very little
known, but it has been reared on a good many occasions and from very various
media ; in England from rather dry decaying fungi, from damp debris from a
tree-hole, and from sheep-dung in fields ; on the continent from fungi and also
from the muddy edges of springs. Its abundance in gardens and woods suggests
that its normal breeding places may be moist decaying vegetable matter, such
as accumulations of dead leaves.
Culicoides pulicaris Linnaeus
(Figs. IS, 16)
The precise identity of the midge to which Linnaeus actually applied the
name Culex pulicaris is to some extent a matter of conjecture, but it was
certainly one of the larger Culicoides, and the name is now in general use for
a common species which has somewhat milky wings clothed with hair on the
greater part of their surface and with rather sharply defined dark markings
which include three blackish spots on the front margin and a small dark spot
in the middle of the cubital fork. The wing-length is rather variable, but
averages about 2 mm.
FIG. 15.—Culicoides pulicaris, ~L.,\.yp\cs\-io-s:m-. Wmg of
The size and disposition of the dark markings of the wings, and also those
of the thorax, is subject to a good deal of variation, but nearly all specimens
may be grouped into one or other of two rather distinct varieties, each of
which has a lighter form in which the dark markings of the wings are so much
reduced that the wings appear mainly white. In the first variety (arbitrarily
chosen as representing the typical C. pulicaris) the hour-glass shaped dark
mark towards the tip of the front margin of the wing is broadest on the fold
above the upper branch of the median fork, the two branches of this fork are
N E M A T O C E R A — C E R A T O P O G O N I D A E 47
dark to the extreme tips, and the thorax is either unmarked or with three small
and usually separate dark marks. In the second variety (y^r.punctatus Meigen)
the hour-glass shaped mark extends farther across the wing and is broadest
above the fold above the upper branch of the median fork, there is a very small
pale area at the extreme tip of each of the two branches of this fork, and the
thorax usually has three fairly large irregular dark marks which are often
partially fused.
C.puUcaris occurs throughout Britain, and though usually less numerous
uffi V r T frequently (especially in moist seasons)
ufficiently abundant to be a most troublesome pest. Like most of the other
species. It IS most abundant and troublesome in the early summer • it is usuallv
most active in the afternoon or evening, though Goe'tghebuer'rep t^^t s
troublesome during the middle of the day p n as
floaH,t f C puluaris have on several occasions been found among
floating green algae in ponds. ^
Culicoides halopliilus Kieffer
(Fig. 17)
-I C.pul^car^s, of which it has been considered
the n o r' f r ^ wing-markings,
he mechan fork containing two dark spots or streaks instead of only one a
C i " " " ' ? W'ng-markings in many specimens are more suffuLd than
nd i f 'r^ ^ ^^ ^^e tip of the wing above
and including the upper branch of the median fork, but this is by no means