116 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



of September 7-8 we took 7,368 moths of Crambus teterrellus, 468 of 

 them in the single 15-minute period from 7.15 to 7.30. The interest 

 and faithfu'ness of Mr. W. B. Cartwright, my assistant at the time, 

 deserve mention and I am glad to acknowledge my indebtedness to 

 him. 



Collections were made on 18 full nights between the first of June 

 and the middle of October. Collections were attempted on numerous 

 other occasions but during the night the weather conditions became 

 such that the moths ceased to come so none of those records are in- 

 cluded in the present discussion. No moths of teterrellus appeared on 

 October 7 or 12. On the remaining 16 full nights of collecting 19,655 

 teterrellus moths were taken, an average of 1 ,228 per night. The largest 

 number taken on one night was 7,638 on September 7, and the smallest 

 number, 7, on October 1. 



Teterrellus is a species without distinct generations and the moths 

 are quite uniformly abundant from the time they first make their 

 appearance in the spring until about the end of September when they 

 disappear for the year. Their numbers often diminish during a pro- 

 longed dry spell in the summer but increase quickly with renewed 

 rains, these conditions seemingly having more influence on their 

 abundance than any periodicity of generations. 



Of the total of 19,655 moths taken 13,318, or 67.8 per cent, were 

 males and 6,337, or 32.2 per cent, females. As can be seen from 

 Chart A the percentage of males varied on different nights from 32.7 

 to 100. On only five nights did the number of females taken exceed 

 the males, the total excess for the five nights being but 312. It was 

 very soon noticed that the great majority of the females appeared very 

 shortly after dusk, generally within an hour and that comparatively 

 few of the males came early in the evening. After the first flight was 

 over there was an interval of comparative quiet after which the num- 

 bers again increased but more gradually than before. This increase 

 consisted altogether of males and continued until the totals attained 

 were greater than during the first flight. The maximum of this second 

 or male flight was reached generally between 11.30 and 1.30. Chart B 

 in which the total collections for the season are graphically repre- 

 sented for each 15-minute period of the night shows this relation of the 

 sexes at a glance. It will be noticed that the females have reached 

 their peak and as suddenly subsided by 8.30, from which time there 

 is a very uniform and gradual decrease in their numbers until daybreak. 

 Chart C is a representation of the facts in another form. By reference 

 to Chart D it will be seen that over 41 per cent of the females have 

 come by 8.30. The males, on the other hand, have scarcely begun to 

 come by 8.30, only 3.9 per cent of their total number having appeared. 



