How to distinguish Mosquitoes from other Flies 



adult state may, for example, be briefly described in the following 

 way: 



The adult mosquito lays its eggs on the surface of water. The 

 eggs float on the water for some days (two to four), after which 

 time they hatch and permit of the escape of the larva. 



The larva is a free swimming, worm-like animal, which eats 

 greedily and grows rapidly, casting its skin several times in the 

 process, till it reaches its full development. At this stage it 

 suddenly changes its form ; casting its skin, the worm -like larva 

 assumes a comma shape, and so becomes the pupa or nympha. 



During the pupal period the insect ceases to eat ; profound 

 anatomical changes take place within the pupal skin, whereby the 

 masticatory mouth parts of the larva are converted into the suctorial 

 apparatus of the adult insect or imago. After a certain number 

 of days the pupa-case ruptures, and the adult insect is liberated, 

 furnished with wings and legs adapted for a life in the air. 



The Diptera have been divided into two great groups, termed 

 Orthorrhapha and ^yclorrhapha, according to the manner in which 

 the pupa-case splits to permit of the escape of the perfect insect. 

 In the Orthorrhapha, which includes the Culicidoe (mosquitoes), the 

 ChironomidcB (midges), the Simulidce (sand-flies', the Cecidomyidce 

 (gall-midges), the Mycetophilidce (fungus-midges), the Tipulidce 

 (daddy-long-legs), the TabanidcB (horse-flies), etc., the pupa-case 

 splits longitudinally down the median dorsal line. In the Cyclor- 

 rhapha, which includes the Syrphidce (hoverflies), the Oestridce 

 (bot-and warble flies), the Muscidce (houfee flies, tsetse flies, blue and 

 green bottle flies, flesh flies, etc.), the perfect insect escapes by the 

 splitting off of a cap from the head end of the pupa. 



The members of some of the above families are not infrequently 

 mistaken for mosquitoes, especially the ChironomidcB or midges, the 

 Cecidomyidce or gall-midges, the Tipulidce, the Simulidce, and the 

 Psychodidce or owl-midges. Mosquitoes may, however, be easily 

 distinguished from any other flies by the following characters : 



(1) They possess a long sucking proboscis.* 



(2) The veins on their wings are covered with scales. 



(3) The arrangement of their wing-veins is characteristic and 



different from that of the members of any other family. 



* Except in the genera Corethra and MocJilonyx. 



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