214 MOSQUITOES OF NORTH AMERICA 
distance, if necessary, to lay their eggs. Where, however, a suitable breeding 
place lay near at hand they did not appear to pass it over. 
“ (2) The maximum distance of flight of A. rossi is not known with certainty, 
but under the conditions at Mian Mir the experiments showed that they flew to 
and fro a distance of more than half a mile. 
“ (3) The breeding places of A. fuliginosus were in no case nearer than 1000 
yards from the situation where the adults were captured. 
“ (4) In the later part of the season it was difficult to understand where adult 
A. culicifacies came from unless distances of half a mile or more were traversed 
by this species. 
“Tt is obvious that in any attempt to estimate the probable efficacy and 
practicability of efforts at destruction of ‘ anopheles,’ these conclusions are ex- 
tremely important.” * 
The Sergents in Algeria found that the breeding-places are generally to be 
found from 100 to 300 meters from infested houses, but in the case of the railway 
station of Ighzer-Amokran, absolutely isolated in the Valley of the Soumman, 
the station contained adult Anopheles while the nearest breeding-place was dis- 
tant one kilometer. The mosquitoes found in the station were in good con- 
dition. The authors do not mention the possibility that they were brought there 
in the railway coaches. Further observations by these authors, at Mondovi, 
showed adult Anopheles at a distance of two kilometers from breeding-places 
but they ascertained that this distance was traversed by successive short flights. 
It is obvious, then, that these mosquitoes do not progress by direct flight for 
considerable distances but usually spread by other means. A succession of short 
flights, e. g., from areas in which they are abundant, will carry them farther 
than by any single direct flight. Moreover, the adults are frequently carried by 
railroad trains and in other conveyances for long distances. This question we 
have considered in regard to mosquitoes in general in another section. 
That Anopheles perhaps may be carried, exceptionally, for considerable dis- 
tances by winds is indicated by the observation of Surgeon A. C. H. Russell, 
U.S. N.; he sent us a specimen of A. annulipalpis Arribalzaga, with the state- 
ment that it was one of a considerable number of mosquitoes blown aboard the 
U.S. 8. Newark in June, 1903, at anchor off Montevideo, more than two miles 
from the shore. Carter credits Goldberger with the observation that Anopheles 
albimanus appeared on board a ship, at Vera Cruz, anchored half a mile from 
shore. 
In a most suggestive address, delivered before the Section of Preventive 
Medicine of the Congress of Arts and Sciences at the St. Louis Exposition in 
1904, entitled “ The Logical Basis of the Sanitary Policy of Mosquito-Reduc- 
tion,” Dr. Ronald Ross considers the whole question of the spread of mosquitoes 
from their breeding-places, both in communities in which anti-mosquito work is 
being carried on and from outside breeding-places from which cleared areas may 
be restocked. He states that the problem which governs the prophylaxis of 
malaria through mosquito control may be stated in the following words: “ Sup- 
pose that a mosquito is born at a given point, and that during its life it wanders 
* A Monograph of the Anopheles Mosquitoes of India. S. P. z 
Calcutta, 1904. PD q' James and W. Glen Liston; 
