EEVISION OF NEAECTIC TERMITES. 99 



wise inaccessible can be reached; for example, some termites have 

 colonies in the buttresses of the few remaining large bald cypress 

 trees (Taxodium distichum) in Lake Drummond, Dismal Swamp, near 

 Wallacetown, Virginia. (PI. 15.) 



Unless carried by the wind, termites do not fly very far. The great 

 majority of the colonizing adults in the genus ReticuUtermes and other 

 subterranean species, after a short vacillating flight, alight or fall 

 to the ground and lose their wings. The night-flying species of the 

 family Kalotermitidae are stronger fliers. 



DIUKNAL SWARMING. 



The species of ReticuUtermes in the eastern United States (north of 

 Georgia) always swarm during the daytime; in the vicinity of 

 Washington, District of Columbia, usually in the morning or about 

 noon. The species of this genus have never been collected at lights, 

 at night, so they are probably not nocturnal in habit. Rainfall is 

 not a factor that induces swarming in the more humid east. 



Amitermes tubiformans Buckley and perplexus Banks swarm during 

 the day in Texas. 



Small, inconspicuous termites swarm during the daytime. 



NOCTURNAL SWARMING. 



Species of the genera Termopsis, Ralotermes, Constrictotermes, and 

 Nasutltermes are night-flying termites, and their winged adults have 

 been collected on the wing at lights at night, to which they are 

 attracted. In the case of Termopsis angusticollis Hagen and neva- 

 densis Hagen the swarm usually begins at dusk, but the insects con- 

 tinue to fly until late in the evening. The same is true of Ralotermes. 

 Large, conspicuous termites swarm at night. 



In arid or dry sections of the country, as in certain portions of the 

 Southwestern States, on the prairies and Great Plains, termites 

 usually swarm after a rainfall or during a light drizzle, as is char- 

 acteristic of many termites in the Tropics. This is because of the 

 dry hard ground in which otherwise the insects could not become 

 established. These conditions do not prevail in the eastern United 

 States, where the ground is usually more moist and favorable. 



SEASONAL AND OTHER VARIATIONS OF SWARMING. 



The different species of a genus rarely swarm at the same time in 

 the same locality. 



The dates of swarming, or the colonizing flights of termites, vary 

 with the species and the geographical location, and also with the 

 season. Observation has shown that the dates of termite swarming 

 can be correlated with the seasonal development of certain forest 

 trees, and that the actual dates of the month are of no importance. 



