17 



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 ma}' be worth while once again to 

 emphasise the fact that, proper!)- used, the\- apply to any species of 

 the family Culicidre, 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 niosqnitoes 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 A'luies, the species of mosquitoes now 

 recognised as British are twenty-two in number. Many harmless 

 midges belonging to the genera Chirononius and Tanypus resemble 

 gnats more or less closely in outward appearance, but, apart from 

 other structural characters, may be distinguished hy 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 se.x. The males may be distinguished by their plumed 

 antennae, and in the genera Theobaldia, Culex, and Grabhaniia 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), v,'hich 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 



