But

September 14. On my return to-day from a few days' absence, I sent my man into the acre lot of potatoes to look after the beetles. In about two hours he reported over 1,000 beetles, and a very few slugs destroyed on the two outside rows around the field. The beetles seem to have collected on the rows nearest the fence for protection from the cold of the past few days. The other portions of the field were almost entirely free from them. I confess to a feeling of self-satisfaction, at having thus finally triumphed over these ravenous insects. My potatoe vines were almost entirely free from any appearance of devastation, and the crop fast maturing for harvest, while those of my neighbors were mostly ruined. "Now, Mr. Whitlock," said I, "let us go into lot 112, it is but a small patch, and just whip around the outside rows, and our triumph will be complete. We shall have no more trouble with them this season." what was my utter astonishment on going into the lot, to see, on the three rows next to Mr. Scott's patch, thousands upon thousands, and ten times ten thousand of thousands of these beetles, covering every leaf and stalk remaining upon these rows; slowly, steadily, but perceptibly moving forward to the fourth and fifth rows, devouring as they move, and leaving naked desolation behind them. They had made a general immigration during my absence, from the patch of Mr. Scott, and another patch adjoining his, which, although comparatively so free from ravage at an earlier stage of the season,-owing as I had concluded, to a later planting, or difference in variety,— had later in the season been entirely devastated by them, and the crop ruined. For this reason they had crawled through the fence and made a general onset upon the vines in my yard. I saw at once that it was useless for me to spend time over them. I was completely "out-flanked." My only consolation was, that owing to the near maturity of the crop, they could work me no further damage, and to the fact that the frosts would in a few days at most, stew them and the vines up together. So we concluded to leave them to their feasting and their fate, with the understanding that I was to have the

privilege of using them for experimental purposes during the remainder of the season.

September 16. Clear and cold all day. Tried an experiment with boiling hot water, sprinkled from a watering-pot, upon a hill of potatoe vines, covered by over 300 beetles. They dropped instantly, at the touch of the water. But the shower was continued upon them until the vines wilted as from the effect of a severe frost. The vines were then lifted; the beetles were found lying on their backs, the ground literally covered, but all, except about twenty, "alive and kicking."

September 17. Frost this morning; but not sufficiently severe to kill the potatoe vines, or to have any sensible effect

upon the beetles.

September 18. Frost again this morning; but the beetles are still alive and in full action in lot 112. Toward evening I brushed off the beetles from several hills of the vines, and turning the vines away from them, left them exposed upon the naked ground, in order to test their power to endure the cold.

September 19. Frost again this morning. The ground slightly frozen. The beetles are still alive, and slowly crawling back to the vines. The warm rays of the sun revives them rapidly. They have advanced on lot 112 two rows within the past five days. Not a leaf is left behind them. There is not a live slug anywhere to be seen. They all disappeared on the approach of cold weather. Where they all went to I do not know; but I saw several of them in the act of burrowing in the ground. On searching, however, I have not been able to find any of them. They may have penetrated to a considerable depth, to the effects of frost or other exposure. escape October 6. My man reported to-day, that on making an excavation for the carcass of a cow, on the premises of one of my tenants, he discovered at the depth of four and five feet, a dozen or more beetles in a partially dormant state. On being exposed to the sun and air, they became lively and active.

October 23. The ground was frozen at least an inch in depth this morning; yet numbers of beetles were found, still alive, where my man was digging potatoes. He said he found many beetles in the hills among the potatoes.

November 17. In taking up some fence posts on lot 112, we found many beetles burrowed down the sides of the posts, to the depth of one and two feet. They were alive and able to crawl around, seeking shelter from the cold.

December 30. Mr. Phillips, from Berrien township, was at my house to-day. He informs me that during the month of October he gathered from lot 112, thirty-one beetles. These he buried in an old paint keg, and left them at the corner of his house, exposed to the drippings from the roof. They remained there during the extreme cold in the fore part of this month, (December,) when the thermometer sunk to eight degrees below zero. He then exposed the keg to ninety degrees of heat, until the frost was entirely out of it; then on searching for his beetles, he found thirty of them alive and active! Not having their appropriate food for them, he kept them alive on cabbage-leaves for over two weeks; but they did not seem to eat much. My opinion is, they did not eat at all, or if they did, not enough to have kept them from starving to death in due time. The experiment is valuable as testing the amount of endurance of these insects.

From the preceding notes and observations, the farming community may learn something concerning the character of the enemy approaching them, and the amount of danger to be apprehended.

JUSTUS GAGE.

Dr. Henry Shimer, in an article in the American Naturalist, considers some of the causes why the Colorado potatoe beetle was less numerous in Illinois during the season of 1868, than in the previous year. The first is the unusually mild weather during the autumn of 1867, which he thinks induced the pupa of the last brood of the beetle to mature and come to the sur

face, instead of remaining in the ground over winter; the lack of food in the fall, together with the cold, open winter following, destroying great numbers. Another cause which he thinks contributed to their destruction, was the very hot and dry weather of July and August. He thinks the delicate pupæ, "exposed to the dry, burning dust," could not live. He supposes they go into the ground to pass through their transformations, because they are there protected from the "hot, dry atmosphere of summer, and the cold frosts of winter;" but this time the ground failed to give them the proper shelter, and they perished. He says he has often noticed that the 1 pupæ of various insects perish from exposure to too much evaporation.

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