■'^'"'■^ White-grubs and May-beetles. 461 



of their abundance : L. implicita, hirtkula, ilicis, and rugosa. The 

 evening migration occupies not over fifteen or twenty minutes, and 

 m every instance it seemed completed by 8 : 20 p. m. 



"While the evening migration seemed to result in a complete 

 abandonment of the fields by the beetles, yet the observer may now 

 and then hear a beetle whirr past in the darkness at any hour of the 

 night, and light-traps so placed in the open field as not to attract 

 those from the trees will take specimens in small numbers through- 

 out the night. The beetles distribute themselves regularly over 

 large areas when they leave the feeding grounds in the morning. 

 The following is a record of specimens taken in the fields a quarter 

 of a mile or more from trees, and apparently coming directly from 

 them: L. implicita, 11, L. hirticula, 5, L. rugosa, 31, — total, 47. 



All these specimens were taken by hand, the light-traps not 

 seeming to attract them. 



"The morning movement is very early. It varies considerably, 

 according to the clearness of the sky. It is so related to the awaken- 

 ing of the birds that it seems as if the first note of the dick-cissel, or 

 other early bird, is the signal for the beetles to fly to their hiding 

 places in the ground. On only two mornings were beetles taken in 

 June after four o'clock. June 18, a dark cloudy morning, a pair 

 of L. rugosa were taken at 4 : 25 a. m. while in copulation on a stem 

 of grass. Ordinarily the movement did not last over fifteen min- 

 utes and it very rarely continued for twenty minutes. On the morn- 

 ing of June 7, however, a strong wind was blowing thirteen to four- 

 teen miles an hour from the south. This greatly retarded the 

 flight of the beetles which had been feeding on trees to the north of 

 the fields, and on this morning it began at 3:35 o'clock and con- 

 tinued until 4:10, when the last beetle seen was taken in flight. 



"The following notes show the variation in the time of the 

 morning movement of the beetles according to the brightness of the 

 morning and its relation to the awakening of the birds : — 



"Morning of June 10, moonlight and very bright. Dick-cissel 

 heard at 3 : 08 ; meadow-lark at 3 : 15; kingbird at 3 : 20 ; the follow- 

 ing, in order given, from 3:25-3:35, — prairie-chicken, brown 

 thrasher, quail, robin, and horned lark. On this morning the beetle- 

 movement began at 3 : 18 and lasted until 3 : 30. 



"Morning of June 18, very cloudy and dark. No bird was heard 

 until 3 : 40, and the movement of the beetles began at 3 : 45 and was 

 complete in ten minutes. About 3 : 30 a.m. was the average time for 

 the first bird note, and 3 : 35-3 : 45 the regulation time for the morn- 

 ing movement of the beetles." 



