The pupa of Tanypus also resembles that of the Culicidce. The respiratory trumpets are long and cylindric. The pupa, however, remains mainly below the surface, attached by its (armed) tail. Further, it has suckers on the dorsal side of the abdomen.

Duration Of Pupal Stage

Taylor gives the following data: S. fasciata, minimum, two days; C. confirmatus, two days; C. jamaicaensis, two days; C. sollicitans, three days; Ce. albipes, two days.

Emergence Of The Imago

As the time approaches for the emergence of the imago the pupa becomes less active, and if disturbed, will not dive far below the surface. Silvery streaks due to air appear on the dorsal surface, and the pupa becomes extended, lying beneath the dorsal surface film. A crack appears in the chitinous coat, and the thorax of the mosquito, with its head bent back underneath, emerges. Then follow the wings and abdomen, while at this time the extremities of the legs still remain in the pupal case, and it is at this stage particularly that the process occasionally fails, for the legs remain attached to the pupal skin, and the mosquito cannot free itself, but in its struggle is eventually drowned. If the process proceeds normally, the head gradually is unbent and the legs drawn out, the front legs bending forward and upward at the "knee joint," and the hind legs backward and upward. The fly, when first hatched, rests quietly on the surface of the water, or, if disturbed, does not fly far. The wings, however, harden sufficiently for flight in about five minutes, but it is not until considerably later-some hours probably-that they attain their normal character.

Celli gives the duration of the complete life cycle as thirty to thirty two days "in the favorable season," and states that from April to September there are ordinarily four or five generations.

Ficalbi has calculated that in four generations from the mother stock two hundred millions would be born. This period is greatly in excess of those given by Taylor, whose observations were made in Havana. He gives as the period from egg to winged insect: C. nigritulus, minimum, nine days; C. confirmatus, seven days; C. jamaicaensis, six days; C. sollicitans, eight days; Psorophora howardii, six days; Ce. albipes, seventeen and a half days; U. lowii, eight and a half days.

Fecundation Of Mosquitos

This takes place soon after the emergence of the imago, so that it is rare, according to Taylor, to find an unfertilized female. Pairing takes place in sunshine, and the male is described as taking an inferior position, by some, while others describe the male as seizing the female. Annett and Dutton have described swarms of males (anophelines) dancing in midge like fashion in the evening. Eggs are laid even by unfertilized females, but they do not develop into larvae.

Length Of Life Of Mosquitos

In captivity they may be kept alive for as long as six months if provided with sugar, dates, bananas, or sherry and water, etc. In nature it would be safe to assume that their life is even longer; the hibernation of anophelines we shall consider later.

Time Of Biting

Though the Culicidce, more especially the Anophelince, on the whole, are nocturnal in their habits, yet many bite during the day time, and in fact not at night. Thus S. fasciata, Durham states, begins biting about sunrise, 6 a. m., but mainly from 12 o'clock noon to 2 p. m., while from 3.30 p. m. to 5 p. m. they cause little trouble, and after dark they are not met with. Ficalbi states, with regard to the same species, that it attempted to bite on the second day after hatching; succeeded in doing so on the third day; it then took three days to digest the meal, and on the fourth day fed again. Taylor states, however, with regard to S. fasciata, that it will bite during the day or night if hungry. C. confirmatus, C. tceniorhynchus, etc., also bite day and night; Cellia albipes will also bite during the day.