ASSOCIATION WITH MAN 205 



While full descriptions, not only of the adults, but of the early stages of the 

 different species of malaria-bearing mosquitoes, together with some remarks 

 concerning the geographical distribution and habits, will be found in their ap- 

 propriate places under the systematic consideration of the genus Anopheles, later 

 in this work, some general consideration of their habits will be given here. The 

 general question of distribution is briefly mentioned under the head of geo- 

 graphical distribution of malaria. 



RESTING POSITION OF ADULTS. 



Much has been said concerning the resting position of Anopheles as compared 

 with that of other mosquitoes. It has been held that Anopheles always sits with 

 its body-axis at a considerable angle to the surface upon which it rests. This, 

 however, can not be relied upon for identification. When Anopheles rests upon 

 a surface, such as the wall of a room, the body is frequently held at only a 

 comparatively small angle to the surface ; in fact, it is sometimes held parallel, 

 but more often at a considerable angle. The angle at which the body is held 

 differs with the species and is characteristic for it. The hind legs are frequently 

 in motion but as a rule hang down with more or less of a bend at the knee joint. 

 In whatever position Anopheles rests, the beak and the rest of the body are 

 practically in the same plane, whereas with other mosquitoes the beak and the 

 abdomen are by no means in the same place. In Culex and Aedes, for example, 

 the appearance is that of being humpbacked. During hibernation, the hind legs 

 are drawn in, and, for the most part, the body is brought close to the wall, as 

 observed by one of the writers (Howard) upon Anopheles quadrimaculatus 

 hibernating in barns in southern Idaho. 



Giles has found an Indian Anopheles, which he claims has exactly the resting 

 attitude of a Culex. This caused him to give it the specific name culicifacies. 

 Grassi states that Anopheles superpictus holds itself rigidly perpendicular to the 

 wall, and the Sergents state that Anopheles hispaniola rests in the same perpen- 

 dicular attitude. Schiiffner has observed the same habit in a Sumatran species. 

 Peryassu states that Anopheles nimha rests and flies like a Wycomyia, with the 

 hind legs raised and curved forward over the body. 



SEMI-DOMESTIC AND WILD SPECIES. 



Several of the species of Anopheles seem to be on the verge of becoming do- 

 mesticated, like Culex pipiens, and the yellow-fever mosquito, and are commonly 

 found about houses. They attempt to enter houses at the times during which 

 they are active and, once inside, remain there. They seek cellars, attics, barns, 

 and outhouses for hibernation purposes. They often find shelter elsewhere, as 

 under culverts and other protected places, but they seem to prefer to get into 

 buildings if possible. 



Mr. A. H. Jennings has pointed out that, in the Canal Zone, Anopheles 

 alhimanus is the semi-domesticated form and occurs everywhere about houses 

 and villages. This species, in fact, is the great carrier of malaria in the Ameri- 

 can tropics. Away from civilization, in Panama and the neighboring countries, 



