462 Bulletin No. 116. [Avgust, 



These data are of special importance as showing the time of 

 night when the beetles are accessible in the trees on which they 

 feed — a subject important to a discussion of measures of prevention 

 and remedy. 



Harits 0? Reproduction. 



With respect, to the reproduction of May-beetles, we need to 

 know at what time of day, in what situations, and especially how 

 soon after emerging, the sexes pair, and when, where, how soon, and 

 in what numbers the females deposit their eggs. Our definite infor- 

 mation as to the pairing of the beetles is not abundant, but is sufifi- 

 cient to show that they pair at night on their food plants. The males 

 are much more active than the females, — a fact illustrated by their 

 greater abundance at lights in fields at a distance from trees. In 

 the product of the light-traps used in 1906, as described in this paper 

 under "Movements of Migration and Dispersal," pp. 458-460), 

 the males outnumbered the females about 4 to i, while in collections 

 made at the same time from trees the number of males was only 

 39 per cent, of the total number taken. Similar data were given 

 in my Seventh Report.* It will be seen that it does not follow from 

 the greater number of females taken on the food plants that females 

 are actually more numerous than males, but only that the latter are 

 more widely scattered at night, and more generally on the wing. 



It has been noticed by some of the office assistants, and par- 

 ticularly by Mr. J. A. West, that May-beetles are sometimes very un- 

 equally numerous in neighboring trees of the same kind, one tree 

 containing a buzzing multitude while there are comparatively few 

 on another tree of the same species close by. I have myself once 

 seen a large tree so full of May-beetles in the evening that the noise 

 of their movements was like that of a huge swarm of bees, although 

 the condition of the leaves the following day showed that they had 

 not resorted to this tree for food. Their assemblage in tree-tops is 

 evidently in part for breeding purposes, and not wholly for food. 



About fifty pairs of these beetles have been taken by us in 

 copula, all but three of them from trees at night. In one case a pair 

 of L. rugosa was captured at night by Mr. West from a grass-blade 

 in a pasture, and two pairs of L. inversa have been seen copulating 

 in a breeding-cage, also at night. These two pairs had been taken 

 from earthen cells in the ground October 5, 1905, and transferred to 

 the insectary, where they at once went into the earth, first appearing 

 above ground on the ist of the following May. They began to feed 



'Eighteenth Rep. State Ent. 111., p. 117. 



