276 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



such numbers in 1865, passed a second winter, that of 1867, at a mean depth in the 

 soil of forty-one hundredths of a meter, or nearly a foot and a half. The thermome- 

 ter placed in the ground (which was covered with snow), at this mean depth, never 

 rose to 32° F. as minimum. Thus the larvjB survived after being perfectly frozen 

 (probably most subterranean larvae are thus frozen, and thaw out in the spring at 

 the approach of warm weather). In June, 1867, the grubs having become full fed, 

 made their way upwards to a mean distance of about thirteen inches below the sur- 

 face, where, in less than two months, they all changed to the pupa state, and in 

 October and November the perfect beetle appeared. The beetles, however, hibernate, 

 remaining below the surface for a period of five or six months and appearing in April 

 and May. The immature larvae, warned by the approaching cold, began to migrate 

 deep down in the soil in October, when the temperature of the earth was ten degrees 

 above zero. As soon as the snow melted thej- gradually rose towards the surfiice. 



As regards the time aud mode of laying the eggs, we quote from 

 Dr. Lockwood as follows : 



On the evening of the 13th June last we caught in the drug store, Keyport, 

 whither they were attracted by the profusion of light, four Cotalpas, representing 

 both sexes. These were taken home and well cared for. On the 16th a pair coupled. 

 A jar of earth was at once provided and the beetles placed on top of the dirt. In 

 the evening the female burrowed and disappeared. Near midnight she had not 

 returned to the surface ; next morning she had re-appeared. The earth was then 

 very carefully taken from the jar, and, as removed, was inspected with a glass of 

 wide field but low power. Fourteen eggs were found, not laid (as we expected) in 

 one spot or group, but singly and at difl'ereut depths. I was surprised at their great 

 size. Laid lengthwise, end touching end, two eggs measured very nearly three-six- 

 teenths of an inch. They were like white wax, semi- translucent ; in form, long- 

 ovoid and perfectly symmetrical. On the 13th of July one had hatched ; the grub 

 was well formed and very lively. Its dimensions were about five-sixteenths of an 

 inch in length and about three-thirtieths of an inch in thickness. It was a dull 

 white, the head plate precisely that dull yellow seen in the adult grub, the legs the 

 same color, and the extremity of the abdomen lead color, the skin beiug transparent. 

 For food a sod of white clover (Trifolium repens) was given them, roots downward, 

 knowing that the young larvae would come upward to eat. They were then left 

 undisturbed until August 19, when the sod was removed, and it was found that 

 the grubs had eaten into it, thus making little oval chambers, which were enlarged 

 as the eating went on. They were carefully picked out and a fresh sod of grass and 

 clover supplied. They had now grown five-eighths of an inch in length, preserving 

 the same colors. 



It is quite possible that a few of the eggs escaped me in the search. I am of 

 opinion, however, that from fifteen to twenty is the average number laid by one 

 beetle. In short, the insect lays her eggs in the night, probably not more than 

 twenty. The hatching of these required in the present instance twenty-seven 

 days. It must be remembered that a large portion of this time was remarkably 

 cold and wet. It is almost certain that with favorable thermal conditions this might 

 be lessened fully seven days. 



49. Graptodera carinata (Germ.), 



Regarding the habits of this beetle, Mr. W. L. Devereaux writes us 

 as follows : 



I do not remember taking any of Graptodera chalybea on the elm except when the 

 tree was a supporter of a grapevine or else in close proximity to one. There is a 

 Graptodera occurring quite plentifully on elm foliage, however. It is of a greenish 

 hue. I deem it G. carinata. 



