THE LEAF-BEETLES. 119 



of the potato, gnawing large and irregular holes through 

 them ; and, in the course of a few days, begin to lay their 

 oblong oval golden-yellow eggs, which are glued to the 

 leaves, in parcels of six or eight together. The grubs, 

 which are hatched in about a fortnight afterwards, are of a 

 dirty yellowish or ashen-white color, with a darker-colored 

 head, and two dark spots on the top of the first wing. They 

 are rather short, approaching to a cylindrical form, but 

 thickest in the middle, and have six legs, arranged in pairs 

 beneath the first three rings. After making a hearty meal 

 upon the leaves of the potato, they cover themselves with 

 their own filth. The vent is situated on the upper side of 

 the last r,ing, so that their dung falls upon their backs, and, 

 by motions of the body, is pushed forwards, as fast as it ac- 

 cumulates, towards the head, until the whole of the back is 

 entirely coated with it This covering shelters their soft and 

 tender bodies from the heat of the sun, and probably serves 

 to secure them from the attacks of their enemies. When 

 it becomes too heavy or too dry, it is thrown off, but re- 

 placed again by a fres*h coat in the course of a fu\v hours. 

 In eating, the grubs move backwards, never devouring the 

 portion of the leaf immediately before the head, but that 

 which lies under it. Their numbers are sometimes very 

 great, and the leaves are then covered and nearly consumed 

 by these filthy insects. When about fifteen days old, they 

 throw off their loads, creep down the plant, and bury them- 

 selves in the ground. Here each one forms for itself a little 

 cell of earth, cemented and varnished within by a gummy 

 fluid discharged from its mouth, and when this is done, it 

 changes to a pupa. In about a fortnight more the insect 

 throws off its pupa skin, breaks open its earthen cell, and 

 crawls out of the ground. The beetles come out towards 

 the end of July or early in August, and lay their eggs for 

 a second brood of grubs. The latter come to their groAvth 

 and go into the ground in the autumn, and remain there 

 in the pupa form during the winter. 



