Flight and Attraction of Mosquitoes 103 



feet or less from the water surface. It was then 

 that Le Prince, looking over the side of a flat 

 bottomed boat toward the clear sky line, dis- 

 covered the first appearance of the flight of Anoph- 

 eles accompanied by Culex. The flight was from 

 west to east and quite marked. He then selected 

 a place on the opposite bank of the canal from the 

 propagation area and faced it. As it became 

 darker, the quantity of flying Anopheles increased, 

 and, by bending low and looking past a dark 

 object at the clear sky line, hundreds of Anopheles 

 could be seen passing by in one definite direction. 

 They not only traveled in a fixed direction but 

 many appeared to hurry about it. After dark the 

 flight was reduced to practically nothing. During 

 the period of flight, the observers were bitten 

 continuously. Soon after the flight ceased one 

 could remain on the east bank (in the path of the 

 recent flight) and be attacked only once or twice 

 in an hour's time. All night long on the west 

 bank, near the propagation area, and between it 

 and the French canal, hundreds of mosquitoes 

 surrounded and bit an observer. There was no 

 secondary flight period, although observers re- 

 mained to note if this occurred. 



During subsequent evenings, the flight was 

 recorded ; it started about the same time each day. 



