30 BRITISH BLOOD-SUCKING FLIES NEMATOCERA—CERATOPOGONIDAE 31
it must be noted that in 1938, in the course of investigations regarding the
aerial drift of small insects, A. C. Hardy obtained several specimens of
C. pulicaris over the middle of the North Sea.
Whether or not control is feasible, some form of protection from the attacks
of Culicoides is often highly desirable if not essential. Screening is difficult
owing to the minute size of the insects, but some form of mask provided with
a respirator might sometimes be used with advantage by out-door workers.
Smudges and repellants are much used by holiday-makers. In regard to the
former, tobacco smoke is usually helpful, but R. L. Coe has found that a more
efficient alternative in keeping a tent clear of midges is the smoke from burning
incense. A great variety of repellants has been suggested for application to
the skin or hair, but most of them are transitory in their effects, and some are
unsuitable for general use. The following are among those recommended :
(a) A mixture of oil of lavender, i part, and elder-flower water, 20 parts.
FIG. 2.—Diagram of \Wng of a biting midge {Culicoides). I and 2, first and second radial cells. 3,
basal cell. 4, median fork. 5, cubital fork, x, cross-vein.
(Recommended by a writer in Home Gardening, May 1928 ; said to be very
efficacious, one application lasting a whole evening).
{b) Oil of pennyroyal (recommended by J. G. Myers in West Indies).
\c) A mixture of oil of thyme, i part, concentrated extract of pyrethrum
flowers in mineral oil, 2 parts, and castor or olive oil, 5 parts (recommended by
C. Graham MacNay in Canadian Entomologist, August 1938)-
{d) Oil of white birch is effective, but its odour is unpleasant.
\e) Citronella,, i oz., liquid petroleum, 4 oz. (recommended by R. Matheson
as least injurious to the skin).
( / ) Oil of cassia, i oz., brown oil of camphor, 2 oz., lanoline 3 oz., paraffin
wax to stiffen (recommended by Bacot and Talbot 1919; confirmed by A. WMcKenny
Hughes).
The British species of Culicoides were reviewed by Edwards in 1926, 14
being then recognised as distinct. This number has now been increased to
27, mainly by the separation of similar forms which the revision undertaken
in connection with the present work showed to have been confused. These
27 species may be distinguished by the following key :
3-
4-
5
KEY TO BRITISH SPECIES OF CULICOIDES (FEMALES)*
Wings either unmarked or with a single dark spot on the front margin and no additional
pale areas ^
Wings with light spots on a dark ground or numerous dark spots on a light ground (m'aVkings
may be faint) ^^
Wings scarcely I mm. in length and nearly bare ' ^ ^ " 'chi'opterus M g .
Wings longer and hairy nearly all over ^
Body black, wings milk-white ' ^
Body brownish or mouse-grey, wings creamy-white or greyish .'.'.".'.'6
Large species (wing about 2-5 mm.) ; wing with a deep black spot on middle'¿f'front
margin
Small species (wing 1-3 mm.) ; no definite dark spot on wmg heliophilus Edw.
5. Thorax greyish about shoulders, otherwise black and unmarked ; halteres stigma Mg.
Thorax with three confluent black stripes on a greyish ground, and numerous black dots
on shoulders ; halteres black j^ieff.
6. Wmgs creamy-white, often with black hair over radial cells 7
Wings uniformly greyish
7. Legs dark 8
ao. bi^iaf'c^k^ ih ^a^ir^ ^o n wmgs almost confined to radial cells vaelxbaicnasn Ss t aWegr ciw.
Black hair tending to extend in a patch below radial cells 'brunnica7is sp n'
9. CLa-r ger (w, in•g - i - c -2^ -mlinmn .); cunc^t ans Winn.
bmaller (wmg i mm.) j. -r \ , " Winn.
10. lliorax with numerous dark brown dots, at bases of hairs u
Thorax otherwise, markings larger if present
11. Wings with grey clouds on a pale ground ; a dark spot in cubital fork 12
Wings with roundish pale spots on a dark ground ; a pale spot in cubital fork 13
12. Legs mainly blackish nubeculosusM^.
Legs pale • , , • T^- SA
j i , . Kieft.
M , cross-vein ; the lower branch of cubital fork pale circumscriptus Kieff.
IN 0 dark spot over cross vein ; lower branch of cubital fork dark salinarius Kieff.
14. W ings with second radial cell entirely or {pictipennis) mainly dark, and with pale markings
on a dark ground, surface hairy °
Wings with second radial cell mainly pale, and'wi'th'd^Ä'm'a'rking^'ori "a'pak'gr'o'u'nd,'or
else largely bare °
15- Wings with two pale spots on front border, none round 'tip '.'.'.'.'.'.'.'.'.".'. 16
Wings with pale areas round tip in addition to those on front margin 18
16. Hairs present in basal cell V " -V " cV '
No hairs in basal cell . .'.'.•.'.'.•.'.'.'.'.'.•.'.'.•. fasctpcnms Staeg.
17- Thorax brownish, scutellum paler
Thorax dark brown, including scutellum
18. Median fork dark except at tip
Median fork with a pale spot in or near b^s'e'
19- -Thorax with conspicuous marki - - ^
Thorax unmarked
.pallidicornis Kieff.; cubiialis sp. n.
odiatus Austen
. . .truncorum sp. n.; simulator sp. n.
cmgs . odibilis Austen
20. Tip of second radial cell pale ; 'spoi 'in'm'edian'fo'r'k le've'rwith di^ !
21.
20
one above it. .pictipennis
Staeg.
more distally than the one
. . . maritimus Kieff.
22
Second radial cell all dark ; spot in median fork extending
above it
Whigs bare except at tip .'.'.'.'.'.'.'.'.'.'.'
Wmgs hairy on the distal half or more'.'.'.'.'.' ^
on Ae^LgTi e ' t , ?^^ " " " " " " ^^ " remembered that ir ^^
reco-.nisId f n-in .T ^ extensive, and the amount of hair is less,
.nised duung the prmtmg of this book, are described ,
on pp. 146-8.
: in that sex the pale areas
Two additional species,