2g4 Philippine Journal of Science w 19 



seen in the warmer parts of the earth are largely composed of 

 males. 



No mention seems to have been made, in accounts dealing 

 with mosquito swarming, of Anophelines performing this in- 

 teresting act. Two years ago this month (in March, 1917) 

 having had occasion to descend Faculty Hill at the college cam- 

 pus, at dusk, I encountered two or three distinct swarms of 

 Myzomyia rossii Giles dancing in the air, at a height of about 

 2.5 meters above the roadway. Rapidly sweeping my hand 

 through the swarm I caught a few specimens for the purpose of 

 identification, as I did not observe at the time that they were 

 Anophelines, not Culicines. A note of the occurrence was made, 

 but no further observations were had and the matter was for- 

 gotten until March 4 of this year (1919) when, upon returning 

 home from my laboratory at 6.25 in the evening I encountered 

 four distinct swarms within 60 meters of my house, which stands 

 on a rise of ground at the foot of Faculty Hill. These swarms 

 were hovering at about 1.5 meters above the roadway; their 

 music was quite audible, and they were flying against a wind 

 having a velocity of 12 to 15 kilometers an hour, maintaining 

 themselves without the slightest difficulty at any point desired 

 (as, for instance, directly overhead) and following me as I 

 passed through the swarm. 



When my hand swept among them, in order to capture a few, 

 the whole mass darted off to right or left, or up or down the road, 

 with the greatest ease and with a decidedly concerted motion, 

 returning when the disturbance ceased. Hastening to the house, 

 I secured a net and returned to find that they were even closer 

 to the ground than before, the base of the swarm being less 

 than a meter from the roadway; but, as the entire swarm was 

 dancing up and down, the individuals frequently rose to a 

 height of 3 to 4 meters in the air. 



With a couple of sweeps of the net, I caught one hundred 

 twenty-seven individuals out of two of the swarms and I es- 

 timated that each swarm must have contained in the neighbor- 

 hood of a thousand individuals. 



On the evening of March 5 the same phenomenon was wit- 

 nessed about 100 meters farther up the same road, at precisely 

 the same hour. The road at this point was well shaded on both 

 sides by several high trees. The swarms in this case were very 

 much larger than those seen the previous evening. They ex- 

 tended higher into the air and seemed to dance with much more 



