42 
temperature of this water was 18° C. The third locality was an old 
canal bed so nearly dried out after a season of drought that the water 
lay in rather small puddles. In this case the water was very foul and 
aloze of the genus Lyngbya were present. The temperature of this 
water was 25° C., and the conditions were those of extreme stagnation. 
The first locality was discovered by the writer in company with Mr. 
Pratt and the second and third were found by Mr. Pratt. Later, the 
writer in company with Mr. Busck and Hospital Steward Smith, found 
empty pupa skins of A. guadrimaculatus in a dried up surface pool at 
the Washington Barracks, at a time when malaria was very prevalent 
among the troops. Iam informed by Dr. Thayer, of Baltimore, that 
Dr. Lazear found A. punctipennis breeding in a stone quarry near 
Baltimore, in the summer of 1899. Ross found in India that while the 
species of Culex generally bred in vessels of water around the houses, 
the species of the genus Anopheles bred in small pools of water on 
the ground. This point was made the subject of a special investiga- 
tion by the expedition of the Liverpool School of Tropical Medicine 
to Sierra Leone. While Culex larvee were to be seen in almost every 
vessel of water or empty gourd or flowerpot in which a little rain 
water had collected, in only one case were Anopheles larvee found in 
such receptacles. On the other hand, they occurred in about 100 
small puddles scattered throughout the city of Freetown—puddles 
mostly of a fairly permanent description, kept filled by the rain, and 
not liable to washing out during heavy showers. It was noticed also 
that the larvee seemed chiefly to feed on green water weed. 
In the interesting and important paper by Dr. J. W. W. Stephens 
and Mr. 8. R. Christophers entitled ‘*The distribution of Anopheles 
in Sierra Leone,” published in the report of the malarial committee of 
the Royal Society, July 6, 1900, it is stated that at Freetown not 
only do the larvee of Anopheles exist in the small pools in the rocks, 
but also in the pools by the sides of streams and in certain small 
drains, and that in the dry season, in the absence of the rock pools, 
Anopheles breeds freely in streams and drains; also, in the dry season, 
the adults exist in most parts of the town in dwellings, especially in 
overcrowded native huts and native quarters, ready to lay their eggs 
when pools appear. It is interesting to note, from this latter obser- 
vation, that the authors of the paper recommend the destruction of 
dirty huts and the prevention of excessive overcrowding. Outside of 
the city, in the ‘‘ bush,” Anopheles larve were present throughout the 
whole district. In the mountain streams, wherever there were suitable 
pools, multitudes of larve existed. In tracing the mountain streams, 
occasionally for a half mile or so, they found no larve, but then a 
rock pool occurred, and there they were again found in numbers. At 
Songo and Mabang they were able to detect Anopheles larve in the 
swamps. ‘They were not present in the main swamp water on account 
