mm H
APPENDIX A
T H E GENITALIA OF THE BRITISH CULICOIDES
WITH NOTES ON SYNONYMY
By F. W. Edwards, Sc.D., F.R.S.
No detailed comparative study of the male hypopygium of the European
Cuhcoides having hitherto been made, the opportunity has been taken of filhng
this gap in our knowledge in so far as concerns the British species. It was
already known from the researches of Carter, Ingram and Macfie (1920) on
the African species, and of Root and Hoffman (1937) on the American species,
that as m most other groups of Diptera, the male genitalia provide characters
of the highest importance for classification.
The scattered descriptions and figures hitherto published of the hypopygia
of the European species are mostly totally inadequate, as they omit any reference
to the organs which are of greatest importance for classification, the aedeagus
and parameres. Indeed, the only full description of the hypopygium of any
European Cuhcoides which I have been able to find in print is that by
Pomerantzev (1932) of C. mibeculosus Mg. ; this author gives a complete
account of the skeletal and anatomical structures. In addition. Root (1937)
has given good figures of two European species (C". chiopterus Mg. and C
obsoletus Mg.) which also occur in North America, and Vimmer (1932) has
adequately figured one species (C. trivittatus Vimmer) which is evidently very
different from any of those occurring in Brhain or North America.
In the present contribution, figures and brief descriptions are given of all
the species, now twenty-nine in number, which have so far been recognised as
occurring in Britain. The material of European Culicozdes in the British
Museum is extremely scanty, and very few species, additional to those found in
Britain, are represented by male specimens ; figures of these species are
added. ^
The figures here given all show the appearances in ventral view of specimens
mounted without pressure in Canada balsam, after clearing in potash and
staining with carbol fuchsin. It was found desirable to illustrate two or more
specimens of some species in order to demonstrate the amount of individual
variation to be expected as well as specific differences.
Reference to fig. 53 in which the parts are shown diagrammatically will
make clear the terminology employed, but a few further words of explanation
are desirable. ^
The hypopygium of Culicoides is of rather simple structure. To a chitinous
mig formed by a large dorsal plate {mnth tergzte) and a smaller ventral plate
{mnth stermte) are articulated the large forceps (consisting of two segments
the ..r./. and style), and protected by the tergite and coxites are the true
genital parts {aedeagus and parameres). Beneath the distal part of the ninth
9 129