36 DRAGON FLIES VS. MOSQUITOES. 



come swarm upon swarm of the females intent upon satis- 

 fying their depraved taste for blood. This explains why 

 they appear on the field of action almost immediately 

 after the cessation in the strong breeze ; on the supposi- 

 tion that they were blown far inland, this sudden reap- 

 pearance would be unaccountable. 



So local are the ranges of the Culicidje, that every ob- 

 server has noted that they may be seen year after year, 

 flying in tall columns, and breeding swarms in exactly 

 the same localities as the year previous. " E. L. A." ^ 

 describes these swarms as " so vast that they looked like 

 the ascending smoke of a campfire, and so numerous that 

 the_hum of their myriad tiny wings could be heard at 

 least thirty yards." jNIagis ^^ also writes of this habit. 



Unfortunatelv for us, these flights occur at an hour 

 when even the most untiring Odonat has betaken himself 

 to his night's rest, and only the swallow or whippoorwill 

 is likelv to make anv effective attack on these hordes. 

 This must be remembered when we come to a final dis- 

 cussion of the dragon fly as a mosquito destroyer ; their 

 times and habits of flight have but little in common ; not 

 only their daily period of flight but the annual period as 

 well must be noted in this connection. One or two 

 broods of mosquitoes appear in the middle Atlantic sea- 

 board region after the Odonats have become very rare or 

 have entirely disappeared. 



It now remains merely to allude to mosquitoes as pests 

 in other ways than as biters, and our treatment of their 

 life history is finished. As harborers of hsematozoa their 

 menacing character will be discussed in our chapter on the 

 medical aspect of this subject. 



That they have frequently interfered with the arts and 



