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 ring, 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 fresh coat in the course of a few 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 growth 
and go into the ground in the autumn, and remain there 
ln the pupa form during the winter. 
