14 : COMMON WHITE GRUBS. 
stated that his attention was directed to the unusual abundance of 
grubs in his field in the fall of 1911 by the blackbirds which came 
in flocks and followed him as he plowed. He soon learned that they 
were gathering grubs. After picking up several grubs each bird 
would fly back to the trees a short distance away and soon return. 
Thus there was a continuous flight from the trees to the ground and 
from the ground to the trees. Besides crows and blackbirds prac- 
tically all of our common birds feed on white grubs or their adult 
forms, the May beetles. The Biological Survey has found these 
insects in the stomachs of more than 60 species of birds. 
Domestic fowls may properly be classed as natural enemies of 
white grubs, although their usefulness is largely controllable. All 
farm poultry are fond of these insects, and where possible should - 
be given the run of infested fields at the time of plowing. The 
turkey especially is valuable in this capacity, and the writer has 
seen infested timothy and sod fields liter- 
ally overturned by these birds in their 
search for grubs. 
Among the undomesticated mammals 
which feed on the grubs the skunk, or so- 
called polecat, is probably the most valu- 
able,) and, indeed, some farmers have 
gone so far as to attribute the increase in 
these insects to the decrease in numbers 
Fic, 10.—Pyrgota undata, a fly of the skunks, which are being rapidly 
Laan ee Seine killed off by trappers. In a field of 
winter wheat at Lagro, Ind., the grubs 
were reported cutting off the young wheat plants, and when the fields 
were examined a few days later (November 3, 1911) a skunk hole 
3 to 5 inches in depth was found at nearly every stool of wheat which 
had been attacked by the grubs, and in every case the animal had 
invariably captured the culprit. In northeastern Iowa many large 
landowners observed the grub-eating habits of the skunk during the 
recent severe outbreak, and have signified their intention from now 
on of protecting this friend of the farmer. Innumerable instances 
of this nature illustrating the value of skunks could be cited. 
A number of predaceous and parasitic insects have been reported 
as attacking the grubs and May beetles, and of these enemies it is 
probable that such common and generally distributed forms as the 
black digger wasp, Tiphia inornata Say, and another wasp, lis 
sexcincta Fab., both of which attack the grub, together with a fly, 
Pyrgota undata (fig. 10), which attacks the adult beetle, are the most 
1The domestic hog is the most efficient of all grub destroyers where it can be utilized. 
It is fully discussed in this connection under ‘‘ Methods of control,” p. 16. 
543 
