198 



071 the Insects affecting the Tarnip Crop. 



that I put into a quill soon reduced the inside of the cork stopper 

 to powder. The jaws seem to be adapted for keeping in the food 

 during the short process of mastication, and the four feelers hold 

 and steady any portion of the leaf to be eaten^ and assist in con- 

 ducting the detached morsels into the mouth. 



From the experiments so successfully conducted by Mr. Le 

 Keux, it appears that the female beetle lays but few eggs com- 

 pared with most other insects, and that it requires a period of 

 about thirty days to carry the animal through its various stages up 

 to the time when it becomes a perfect beetle again^ viz., it re- 

 mains an egg ten days^, a maggot six, and a chrj salis fourteen 

 days : the beetles themselves are rather long-lived, for they have 

 been kept in that state from July until the following February. 



The turnip-beetle, and all the species of Alticcs related to it, 

 are readily known by the great thickness of their hinder thighs, 

 which gives them the power of leaping, like fleas, to a pro- 

 digious distance, considering their small size. Eighteen inches is 

 about the greatest extent of their leap, which in a straight line 

 would be, averaging their stature, 216 times their own length: 

 and when it is remembered that this leap is performed in a curved 

 line, it must be admitted that a considerably greater distance is 

 achieved. They seldom walk, and when at rest sit with their hind 

 legs folded under them (fig. 6 c), ready to skip off in an instant, 

 if disturbed, or when even approached : in warm weather, during 

 sunshine, with the thermometer standing between 70° and 80° in 

 the shade, they fly with facility. 



This little plague is not confined to our island, for it is abundant 

 in Germany, and common everywhere in Sweden, where it is very 

 destructive in its perfect state. Probably in England no portion 

 of the country is perfectly free from these insects, at least every 

 bank and meadow harbours them to a greater or less extent, and 

 they have been found also on grass lands which had not been 

 ploughed for many years, and where there were no turnips within 

 half a mile. It will be necessary to consider this part of their 

 history before we enter upon a discussion of the remedies. The 

 turnip-beetles hybernate, or live through the winter, in a torpid 

 state, and may be found under the bark of trees, as well as be- 

 neath the fallen leaves, in the chinks of old timber and paling, 

 the stumps of thorns and of other bushes, where the bark does 

 not adhere close to the stem, and the hollow stalks of grass and 

 stubble seem to afford them an asylum during the inclement 

 months of winter ; but inactive as they then are, the warmth of 

 the hand is sufficient to revive them in a few minutes, so that an 

 unusually mild day in January or March will partially seduce 

 them from their retreats, and will render them almost as active as 

 would the ardent sun of summer. 



