228 PROC. ENT. soc. WASH., VOL. 22, NO. 9, DEC., 1920 



July 1 First day song not heard at all at Falls Church, Va. 



July 1 Last cicada heard, note feeble. (Dr. T. E. Snyder.) Note 



from Washington, D. C. 



July 16-20 First hatching of eggs from caged twigs.* 



July 21-31 Nymphs emerged daily by hundreds. 



Aug. 1 Nymphs decreasing in numbers. 



Aug. 12 Last nymphs emerged from cages. 



From the foregoing calendar of events the following periods, 

 covering various phases of cicada activity, were determined. 



LENGTH OF PERIODS. 



EVENT DATE TO DATE TOTAL DAYS 



Maximum nymph* May 24 May 30 7 



Maximum adult May 22 June 20 30 



Maximum volume of song, May 25 June 5 12 



continuous concerts. 



Copulation May 31 June 7-9 8-10 



Oviposition May 31 June 12 13 



Egg May 31 July 16-20 47-51 



Maximum emergence of 



nymphs from eggs. July 21 Aug. 1 12 



First to last adult May 14 July 1 49 



First to last song May 22 July 1 42 



First to last nymph May 13 May 30 19 



First to last nymph from eggs July 16-20 Aug. 12 24-28 



Relation of Temperature to Their Song. 



To determine the relation between temperature and their song, 

 records were taken from a hydrothermograph at the station for 



'" The following insects were taken from cages containing twigs with cicada 

 eggs in them. Although the exact relation they bear to the eggs was not 

 fully determined, the occurrence seems worthy of note. 

 Pinkish thrips. 

 Dipterous larvae and adults, belonging to family Cecidomyidae. (Det. by 



Dr. J. M. Aldrich.) 

 Coleopterous adults, Orthopems glaber Lee., a Corylophid. (Det. by E. A. 



Schwarz.) 

 Corrodentia, one adult and three nymphs of a psocid. Det. by A. N. 



Caudell as Peripsocus californicus Banks. 

 The pinkish thrips are known to be predacious on the cicada eggs. Mr. 



Schwarz says that the coleopterous adults were probably feeding on a 



mold formed about the twigs where they had been injured through 



oviposition. 



"Maximum" = period of greatest abundance. 



