18 CIRCULAR 6 4 3, U. S. DEPARTMENT OF AGRICULTURE 



FLIGHT RECORDS OF INDIVIDUAL SPECIES 



The species of Phalaenidae fall into two main groups based on their 

 seasonal history, namely, those species producing a single generation 

 annually and those producing more than one generation annually. 



As noted previously, species of economic importance comprised 90 

 percent of the total number of individuals captured. The seasonal 

 flight of several single-generation species of economic importance is 

 shown in figures 6 and 7. 



In general, the flight of individual species showed the same trend 

 at all the localities, the chief difference being in numbers taken. 

 Where no striking differences were noted only one locality was plotted 

 on the charts. It will be seen that the species producing a single 

 generation annually have a rather short flight period, usually late in 

 August, extending through September and into the early part of 

 October. The notable exception is Chorizagrotis auxiliaris. The 

 enormous flight of this species in May and June suddenly subsides 

 and the species reappears again in September, after an estivation 

 period of about 2 months. The fall flight is greatly reduced in num- 

 bers. This species is normally confined to the semiarid regions, but 

 occasionally occurs in abundance at Manhattan (fig. 6, B) and at 

 Lincoln. The records for the individual species show the same trend, 

 namely, years of abundance usually followed by years of scarcity. 



The seasonal flight of several species producing multiple generations 

 annually is shown in figures 8, 9, 10, and 11. The flight records alone 

 do not delineate clearly the various generations owing to overlapping 

 as the season progresses. The charts, however, bring out some points 

 of interest with reference to the seasonal abundance of multiple-gen- 

 eration species. Heliothis armigera (fig. 10, A) is shown to be scarce 

 early in the season, with a marked increase in abundance in the fall. 

 With Prodenia ornithogalli (fig. 10, B) and Peridroma margaritosa 

 saucia (fig. 11, A) the peak of abundance is reached in midseason, 

 followed by comparative scarcity in the fall. Protoleucania albilinea 

 (fig. 11, B) shows two distinct flight periods, one early in May and the 

 other late in August or early in September. 



SUMMARY 



Light traps were operated for various periods in six localities in 

 Kansas and Nebraska during the period 1934-37, m order to obtain 

 information on the flight periods and abundance of owlet moths 

 (Phalaenidae). An attempt was made to operate the traps each 

 night during the flight season, which extended from March to Novem- 

 ber. A total of 2,719 nightly records were made. 



During the 4-year period 305 species of Phalaenidae were taken, 

 totaling more than 525,000 individuals. Approximately 90 percent 

 of the specimens taken were species of economic importance. The 

 different species taken in each locality are shown, together with the 

 total yearly flight, the flight period, and the proportion of the sexes. 

 More than 36,000 individuals were examined for sex, and it was found 

 that 35 percent were females. The sex ratio varied greatly with the 

 species. 



The seasonal flight records are presented graphically for the Pha- 

 laenidae as a group and for several species of economic importance. 

 The numbers of moths taken differed greatly in the different localities, 



