PROC. EXT. SOC. WASH., VOL. 22, N T O. 6, JUNE, IQ2O I2Q 



Diurnal Swarming. The species of Reticnlitcrmes in the east- 

 ern United States always swarm during the day time; in the 

 vicinity of Washington, D. C., usually in the morning or about 

 noon of a \varm, sunny day in the spring or summer. Some- 

 times there are large numbers of winged adults present in colo- 

 nies of species of Reticnlitenncs in the eastern United States, and 

 it is probable that there are also swarms in autumn. 



Only one species of this genus (R. aureus Snyder) has ever been 

 collected at night fat light in Arizona), so they are probably not 

 normally nocturnal in habit. Rainfall is not a factor that in- 

 duces swarming in the more humid east. 



Amitermes tubiformans Buckley and A. (?) per plexus Banks 

 swarm during the day in Texas. 



Small inconspicuous species swarm during the daytime. 



Nocturnal Swarming. Species of the genera Termopsis, Kalo- 

 termes, Constrictotermes Holmgren, and Nasutitermes Banks are 

 night-flying termites, and their winged adults have been collected 

 in large numbers on the wing at lights at night; this is probably 

 an aid to mating, by bringing the sexes together. They are 

 strong fliers. In the case of Termopsis angusticollis Hagen and 

 T. nevadensis Hagen, the swarm usually begins at dusk but the 

 insects continue to fly until late in the evening. The same is 

 true of the species of Kalotennes. 



The period of flight of species of Termopsis in the same locality 

 extends over a period of several months in summer and autumn, 

 i. e., often from early to late summer. In this case the flight 

 does not consist of large numbers of adults, but of 50 to 200 

 adults, more or less. 



Large conspicuous species swarm after dusk. 



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 alight drizzle, as is charac- 

 teristic of many tropical termites. This is an adaptive habit 

 probably due to the fact that the ground is dry and hard and, 

 unless the swarm occurred just after or during a rain, the termites 

 could not establish or would have great difficulty in establishing 

 new colonies. These conditions of soil do not prevail in the more 

 humid eastern portions of the United States, where the ground is 

 usually more moist and favorable ; in consequence rainfall has no 

 influence on the time of swarming. 



Seasonal Variations in the Time of Swarming. 



The different species of the same genus rarely swarm at the 

 same time in the same locality; this effectively prevents inter- 

 specific breeding. 



