24 THE WHITE-GRUBS. 
disturbed, however, no amount of rain or severe cold will 
injure them. The old belief that insects go into the ground 
simply to protect themselves against cold is difficult to be- 
lieve, for if they had to go below the frost-line in Minnesota 
they would have to go eight feet deep, and would have to 
be equiped with wonderful organs for such a purpose. 
A second and much larger species is very destructive in 
our state; 1t occurs both in the wooded and in the prairie 
region. Itis Lachnosterna rugosa Melsh., a reddish-brown 
smooth beetle with a very rugose thorax. It is shown in 
fig. 15, plate II). Thisis the white-grub that causes the 
most damage in our state and whose larva is so frequently 
mentioned in agricultural and horticultural papers. During 
the past season this insect has been especially destructive to 
lawns, and has caused a great deal of annoyance to those 
in charge of our public parks and cemeteries. In one case 
many acres of the most perfect lawns were destroyed in a 
cemetery, where large patches of grass turned yellow; when 
such spots were investigated it was found that the whole 
sod could be lifted from the ground, the grubs having cut 
off all the roots. The illustration showing the white-grubs 
(fig. 16, plate III) was taken from such larve found in the 
act of cutting off the roots. They, as well as those of related 
species, do not move in the usual way by means of their 
legs, but push themselves forward in a peculiar way by 
a wriggling motion of their backs. In other words the lar- 
ve use their backs for locomotion, and their legs are simply 
utilized to pull.the roots of plants toward their yery hard 
and horny jaws. When we look at the peculiar shape of 
white-grubs we can clearly perceive why the legs are not 
used for locomotion, nor is much locomotion required, as 
they live underground in very short tunnels where they need 
to move but little, being surrounded by plenty of food. 
Some of our cultivated plants suffer very severely from the 
attacks of these insects and this is especially true of such 
plants as strawberries, and whole fields of them are de- 
stroyed from time to time. As these larve live under the 
ground they are not readily reached by insecticides, and 
consequently they can not be be poisoned like potato beetles 
