2. Scales on head and { thorax (narrow curved { 1. Wing scales small and lanceolate. scales). Abdomen with { _Pyretophorus._ hairs. { { 1. Abdominal scales only on ventral surface. { Thoracic scales like hairs. _Myzorhynchus._ { Palpi rather heavily scaled. 3. Scales on head and { 2. Abdominal scales narrow, curved or thorax and abdomen. { spindle-shaped. Abdominal scales as tufts Palpi covered with { and dorsal patches. _Nyssorhynchus._ thick scales. { 3. Abdomen almost completely covered with { scales and also having lateral tufts. { _Cellia._ { 4. Abdomen completely scaled. _Aldrichia._ NOTE.—Of the above genera only _Cycloleppteron_ and _Aldrichia_ are unproven malarial transmitters. The female anopheline mosquito alone bites man, the male feeding on fruits and flower juices. The female absolutely requires blood for the development of her eggs after fertilization by the male mosquito. The anopheline mosquito bites at night or toward evening and selects some dark place or dark colored wall to sleep against during the day. Hence the advantage of a buff colored wall interior. It is well to remember that the malarial incidence may be kept down by killing the mosquitoes inside of a house by striking them with a folded paper or piece of wire gauze on a handle (fly swatter). It is not a bad plan to have a dark colored surface in a room to attract them and make their destruction easy. Anophelines do not like wind and seek protection of underbrush. As regards distance of flight from breeding places Metz has noted that _A. crucians_ were not distributed generally over 7000 feet and rarely were found between 7000 and 9000 feet beyond which distance they were not found. Some anophelines get accustomed to feeding exclusively on animals. Mosquitoes may hibernate through the winter and possibly cause new infections the following spring. Cases of malaria in the spring are however usually due to relapses. Mitzmain’s negative experiments with hibernating mosquitoes _prove man_ to be the _winter carrier_. [Illustration: FIG. 12.—Asiphonate (Anopheline) larva _Anopheles_. 2 Siphonate (Culicine) larva _Stegomyia_] The malarial zygote will not develop in the stomach of the mosquito if the temperature is below 16°C. (60°F.). It would seem that the zygote of _P. malariae_ will develop at a lower temperature than that of the other two species, _P. falciparum_ requiring the highest temperature.