M. Vibert on the Cockcliajfer. 3S5 



advantage. An account of this surrender, and the cause of it, he thinks, 

 may be serviceable to both gardeners and farmers, and therefore has 

 published it to draw attention to the subject. He says he is not a natu- 

 ralist ; but, by dear experience, he knows, perhaps, more of the history of 

 this insect, than those who can prosecute its study free from apprehension 

 of its ravages. 



He describes the May bug, which appears to be the Scarabae v us melolontha 

 (see p. 295.), through all the stages of its growth. The perfect insect comes 

 forth about the end of April, continues visible about six weeks, though he 

 thinks that, individually, they do not live above twenty-five, and perhaps no 

 more than fifteen days : Buffbn says eight, but it is certain they live longer. 

 In ascending from their dormitories they are sometimes arrested within an 

 inch or two of the surface by rain or cold. They couple in a few days after 

 their appearance, the female dying soon after she has laid her eggs, the 

 male dying soon after accouplement. A part only of the embryos of eggs are 

 fecundated ; many eggs remain unhatched. Some think they lay from fifty 

 to one hundred eggs, but our author could never find above thirty or thirty- 

 five. In laying, the female makes a hole in light soil, and especially where 

 there are dung droppings, of six or seven inches in depth, which costs her 

 an hour's work ; lays chiefly in the night, though sometimes in the day ; im- 

 possible to tell how long she is laying her quantity. Thinks the eggs hatch 

 in about three weeks ; has found, on the 10th of July, the young grub 

 above half an inch long ; thinks that during the two first weeks of their 

 existence they do not live on the roots of plants, but on particles of decom- 

 posed vegetables, though they begin to be destructive in less than two 

 months. Their ravages, however, do not appear till the autumn ; at the 

 end of October they are about half an inch in length, and as thick as a little 

 goosequill ; their size differs according to the time at which the eggs are 

 laid. This difference of size is observable even to the end of their 

 second year; they descend about 2 ft. into the earth in the month of No- 

 vember, where they make a smooth round hole, and in which they lie stiff 

 and curled up during winter. This hole they leave about the 10th of 

 April, and rise to the surface of the ground; though without taking 

 nourishment, they become larger in size during their rest. Throughout 

 the summer of this year they are inconceivably destructive, and in the 

 autumn return to their dormitories, having acquired four fifths of their 

 size. In the spring they remount for the second time, and begin the third 

 and last year of their existence ; their voracity increases during the short 

 time they have to live, as for two months and a half their depredations are 

 terrible. 



Some time before they descend for the last time, their colour becomes a 

 dull yellow, especially about the tail ; and, during their life, they several 

 times cast their skin or slough, and some of them perish while undergoing 

 this change. Towards the 15th of June they begin to descend to a greater 

 depth in the soil ; where, after having lived in the form of grubs for the 

 space of two years, which include three summers, they are changed into 

 the chrysalis state. 



It is rather difficult to fix the time of their change from the chrysalis to 

 the perfect state, but M. Vibert conjectures that it is towards the end of 

 February; but their under-ground history is involved in obscurity, because, 

 in our labours of trenching and digging, we often find perfect insects in 

 October and throughout the winter months, of their full size and natural 

 colour. These must be either retarded or premature changes, and, as they 

 are against the general laws of nature, deserve the attention of naturalists. 



Buffbn has led us into error by saying that these grubs live three or four 

 years ; by which, probably, he means their whole existence from the egg to 

 the perfect state. M. Vibert divides their existence thus : — 



