i7 
Family 
culicid^. 
Gnats or Mosquitoes. 
In view of the large amount of popular misconception that 
appears still to exist with reference to the meaning of the terms 
"gnat" and "mosquito," it may be worth while once again to 
emphasise the fact that, properly used, they apply to any species of 
the family Culicidae, so that, if we prefer to employ a word of foreign 
origin rather than the Old English gnat, our British species of 
Anopheles, Culex, etc., are as much entitled to be called mosquitoes as 
are tropical species belonging to the same genera, from many of 
which they would be indistinguishable to the untrained observer. 
Including certain non-blood-sucking forms belonging to the genera 
Corethra, Mochlonyx, and Aedes, the species of mosquitoes now- 
recognised as British are twenty-two in number. Many harmless 
midges belonging to the genera Chironomus and Tanypus resemble 
gnats more or less closely in outward appearance, but, apart from 
other structural characters, may be distinguished by the absence 
of the long, piercing proboscis, as also by the habit of holding 
up the front legs when at rest, whereas a gnat in the same position 
elevates its hind legs. In British, as in all mosquitoes with possibly 
one or two exceptions, the blood-sucking habit is confined to the 
female sex. The males may be distinguished by their p*lumed 
antennae, and in the genera Tkeobaldia, Culex, and Grabhamia by 
their elongate palpi. In Anopheles the palpi are as long as the 
proboscis in both sexes, but in the male their tips are thickened, bent 
outwards, and somewhat plumose. 
The preliminary stages of all mosquitoes are passed in water. 
The wriggling larvae and comma-shaped pupae of the common gnat 
{Culex pipiens , Linn. — Plate 8), which are familiar objects in cisterns 
and rain-water butts in summer, may be taken as types of those of 
the species belonging to the genera Theobaldia, Culex, and Grabhamia. 
In the case of the latter genus the eggs are usually laid singly. The 
eggs of the species belonging to the two former genera somewhat 
B 
