I30 B R I T I S H BLOOD-SUCKING FLIES
tergite are two pubescent flaps (cerci), which are the only hard parts of the
tenth or anal segment ; these are of no value in classification and are omitted
from most of the figures. The aedeagus (so-called) is a movable piece which
may appear very different in shape in diiferent mounts, according to whether
Its apex is directed backwards or downwards, an important point to remember
in making comparisons. The coxites have each two internal processes at their
base, a z'enfra/ root passing immediately beneath the aedeagus and a dorsal
root articulating with the base of the parameres ; as first pointed out by Root
and Hofiman the ventral root is a structure of considerable taxonomic importance.
The membranous area connecting the sternite with the aedeagus is in
some species entirely bare, in others more or less densely covered with microscopic
spicules, the condition of this membrane being apparently constant for
any one species.
The most surprising result of this examination has been the discovery that
on hypopygial characters iT. stig^na Mg. and C. parroti Kieff. fall in the same
group with C. nubeculosiis Mg. and C. riethi Kieff., a relationship which would
not have been suspected from their external appearance, though it is also
indicated externally by one or two other features such as the presence of 8 to lo
long bristly hairs on the margin of the scutellum instead of the usual 3 to 6, the
presence of a pair of small tubercles on the front, and the shape of the fourth
tarsal segment, which tends to be rather shorter than usual and is sometimes
more or less cordiform. Another result, less unexpected, has been that certain
species, notably C. vexans and C. fascipemiis (as hitherto understood in this
country) prove to be composite. The following appears to be a natural grouping
of the British species according to hypopygial characters :
A . Parameres fused at base ; aedeagus usually bifid at tip.
C. stigma, parroti, 7iubendosus, riethi.
Parameres quite separate, aedeagus never bifid.
1. Tergite with apico-lateral processes well-developed; usually with
median notch ; parameres various but without tuft of fine hairs at tip.
a. Ventral root of coxite foot-shaped.
C. vexans, albica7is, brumiicans, tru7ico}-n7n.
b. Ventral root of coxite simple (long or short).
C. fascipe7mis group, C. pictipe7i7iis group, C. cu7icta7is, heliophilus,
pu77lilus.
2. Tergite with apico-lateral processes reduced or absent ; without median
notch.
Parameres with fine hairs at tips.
C. pulica7-is, halophilus, i77ipu7ictatus, araiatiis.
Parameres simple.
C. obsoletus, chiopterus.
As IS so frequently the case among insects, the female genitalia offer very
much less tangible characters for classification than do those of the male ;
nevertheless, certain species are well distinguished by the form of their spermathecae.
The relationship of the four species C. stig77ia, parroti, 7iubeculosus
B
a.
a.
G E N I T A L I A OF CULICOIDES 131
and 7-iethi is confirmed by the fact that they all possess a single spermatheca
which is either of irregular shape or with an oblique opening into a wide duct.
Two more species {C. salinaritis and circimiscriptus) also possess a single
spermatheca, but in these it is of regular oval shape with a short neck opening
into a narrow duct. All the remaining British species (including those with
unspotted wings) have two functional spermathecae which are broadly oval or
slightly pear-shaped, and a third rudimentary one. It is interesting to note
that according to Root and Hoffman the same three types of spermathecae are
g
f 1
FIG. 52.—Spermathecae oi Culicoides : parroti stigma; c, Jiubeculosus ; d, riethi; e-g, puncti-
(e, Dardanelles ; f, Baghdad ; g, Madeira, two specimens); \i,pumilus ; i,circumscriptus.
found among the North American species, and, as in Europe, the large majority
of the species belong to the third group. The principal types are illustrated
in fig. 52.
The synonymy here suggested is mainly that which appears to me to be
probable from a study of the published descriptions ; much of it needs checking
from a re-examination of the types, where these exist (many are probably lost*
In a few cases I have come to conclusions different from those of Goetghebuer
regarding the significance of Kiefifer's names.
C. stigma Mg.
(Fig. S3, b-, fig. 52, b)
Ceratopogon stigma Meigen, 1818, Syst. Beschr. i, 73.
Culicoides kiefferi Goetghebuer, 1912, Ann. Biol, lacustre. 5, 3 (sep.).
Culicoides tinimacidatus Goetghebuer, 1920, Mem. Mus. Belg., 8, 57.
Culicoides cordiformatarsis Carter, 1916, Ann. Trop. Med. 10,'134.
Tergite of unique form, its distal margin divided into four lobes of which
the outer pair (the usual apico-lateral processes) are narrower and the inner
pair broader and more rounded, but all of about equal length. Sternite deeply
emarginate. Coxite of unusual shape, being widened on its inner face subapically
as well as basally ; 'ventral root short and blunt. Style with only
about the basal third swollen and hairy, tip rounded. Aedeagus with two long
sharp points.
Spermatheca single, of very peculiar form, globular with a thumb-like
appendix ; ring on duct not evident.