192 



Eckstein (F.). Die Verbreitung von Anopheles in Bayern und ihre 

 mutmassliche Bedeutung fiir die Einschleppung der Malaria. 



[The Distribution of Anopheles in Bavaria and its Importance 

 in connection with the Introduction of Malaria.] — Zeitschr. angew. 

 Ent., Berlin, viii, no. 2, May 1922, pp. 229-282, 1 map. 



Some of the earHer results of these investigations, made in 1919-21, 

 have been noticed [R.A.E., B, viii, 171]. 



The female of Anopheles plumheus (nigripes) does not appear to go 

 far from the tree-holes that constitute its breeding places. The larvae 

 are most frequently found in beech trees, probably because they 

 commonly provide suitable hollows. It appears to hibernate in the 

 egg stage and to have 2-3 generations in the course of a summer, 

 the number depending largely on the early transfer of the eggs into 

 water by heavy showers, and under particularly favourable conditions 

 a fourth generation may be possible. A. plumheus is not plentiful, 

 probably owing to the specialised breeding places required. It is 

 widely distributed, and has been found at altitudes of about 3,300 ft. 

 Being distinctly a forest species, its importance as a carrier of malaria 

 is extremely slight and probably non-existent in practice. 



The female of A. maculipennis hibernates in cellars, sheds and 

 untenanted rooms, sometimes in stables. It prefers more sheltered 

 and drier positions than those sought by the females of Culex pipiens. 

 Very slow-flowing clear water is preferred for oviposition, but rain- 

 water barrels with fairly clean contents are also used. The males 

 appear somewhat earlier than the females from the same batch of 

 eggs ; they remain near the breeding place. The development of 

 A. maculipennis requires 3-4 weeks and in each of the three years 

 there were three generations. 



A. bifurcatus is not so particular as A. maculipennis in its choice 

 of breeding places, polluted water — such as flows from factories — 

 being used, and it also seems to be more numerous in high districts. 

 It is less prone to enter stables, preferring the open air. In general 

 it is more aggressive and bites at all times of the day, even in cool, 

 rainy weather, which is rarely the case with A. maculipennis. It 

 hibernates in the larval stage. The fact that nearly all the larvae 

 in a breeding place are of the same size is against the assumption 

 that females can hibernate also. The hibernated larvae seem to 

 complete their development by the middle or end of May, sometimes 

 earlier, so that the adults are present from mid-May onwards. From 

 this date the larvae disappear until August and September. Even in 

 October the females bite readily. In September and October they 

 lay the eggs from which the hibernating larvae hatch. A. bifurcatus 

 thus appears to have only two annual generations. As it is quite 

 possible that a high-lying locality apparently free from A. maculi- 

 pennis may also seem free from A. bifurcatus owing to the examination 

 being made when the larvae have completed development, a second 

 spring examination or one in autumn must be made before the locality 

 can be pronounced to be free from infestation. 



The author's observations point to A. maculipennis being, like 

 A. bifurcatus, but more so, a pest of domestic animals rather than of 

 man. If cattle and goats are housed together, more mosquitos settle 

 above the goats, probably because they seek the darkest corners. 

 Few mosquitos occurred in stables, and where horses and cattle were 

 kept together they remained near the latter. 



