xv, 3 Banks: Anopheline Mosquitoes 285 



vigor, the wind at that time blowing at only about 9 to 10 kilo- 

 meters an hour. Out of these swarms seven hundred ninety- 

 four mosquitoes were captured, all males, though sweeps were 

 made at the edges of the swarms in the hope that females might 

 be lurking on the outskirts. As night fell very rapidly, it was 

 impossible on either of these occasions to ascertain the presence 

 of females by observing a different character of flight between 

 the two sexes. 



It should be noted here that on the evening of the fifth a 

 great number of females of this species was taken in the house 

 at light, and they were also found in considerable abundance 

 clustering and flying close to the nipa roof of the veranda, a 

 favorite hiding place for Anophelines and a place where thou- 

 sands of them must be captured nightly by a certain little spider, 

 the habits of which are to be described elsewhere. 



Further observations, made on the evening of March 6 at 

 the same hour, revealed other interesting and important fea- 

 tures of this swarming of Anophelines. Having stationed 

 myself at 6.15 in the evening, at the upper part of the road 

 nearly opposite the Forestry Station, I noticed some half dozen 

 males of M. rossii flying swiftly up and down the road, about 

 1.5 meters above it. Within five minutes several hundreds had 

 assembled, and within five minutes more there were many 

 thousands, grouped roughly into three distinct clusters about 

 8 to 10 meters apart, each cluster connected with the others 

 by numerous stragglers. Selecting a favorable spot, which 

 would place the swarms between me and the sky, which was 

 then of a pinkish blue, I waited to see what would occur. 



At 6.30 the first female was seen to be caught by a male, 

 and the pair flew slowly and obliquely upward and away from 

 the swarm and was soon lost to sight. At intervals of about 

 fifteen seconds other females were observed and this continued 

 until 6.40; so that approximately fifty females were seen to 

 enter the swarm and to be seized by males, each time the pair 

 flying slowly but directly out of the swarm. Two pairs were 

 seen to separate after about thirty seconds in copulation. At 

 6.45 the swarms had diminished more than half and at 6.50 

 only a few stragglers could be seen against the rapidly darken- 

 ing sky. 



Whether the mosquitoes came from the thick undergrowth 

 at both sides of the road, as is probable, or whether they flew 

 up or down the road, it is impossible to say; but the rapidity 



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