INSECT ENEMIES OF EASTERN FORESTS 171 
wood and coniferous roots, as well as those of grasses and a small 
series of herbs. The relative size of roots and grubs, however, seemed 
to determine somewhat the manner of feeding. For example, large 
Phyllophaga usually cut off seedlings just below the ground surface, 
whereas small Phyllophaga, Serica, and Diplotaxis generally con- 
sumed lateral roots and stripped the bark from the tap roots. Ap- 
parently this feeding difference is due to mechanical adaptations of 
the various-sized grubs rather than to selective feeding. The feeding 
patterns of the various genera are not characteristic, especially for 
larvae of the same size, and for this reason a key based on feeding pat- 
terns is considered impractical. The rate of feeding seems to be 
dependent on the species, size, and vigor of the grubs. 
As far as determined, the lamellicorn leaf chafers generally lay 
their eggs in the immediate vicinity of their food plants. Some fe- 
males may fly a few hundred yards or more before they oviposit, 
but extensive collections show that grub concentrations are directly 
proportional to the proximity of adult food. It is for this reason 
that nurseries and plantations in or very near forest stands, hard- 
woods generally, and pines in the Carolinas and elsewhere, may some- 
times suffer heavy grub injury. Losses of nursery stock may occur 
in decreasing severity for 4 or 5 years in nurseries on newly cleared 
ground, resulting from the infestation present in the soil at the time 
of clearing. 
Many leaf chafers, in that they prefer tender, succulent foliage in 
season. show a successional nature in their feeding habits. In the 
Lake States, Phyllophaga drakei Kby. is the most important and one 
of the earliest emerging species, and on the Huron National Forest 
it feeds on aspen at the time of emergence, undoubtedly because this 
is the first available and attractive food. A few days later the leaves 
of Juneberry (Amelanchier spp.) are out, and P. drake promptly in- 
cludes them as food. Black oak and white birch leaves appear next, 
and the inclusion of these is immediate. Willow and New Jersey 
tea follow in turn, the latter not becoming available before the 
middle of June. Oak is the most important food of P. drakei on the 
Huron National Forest, both because it is relatively abundant and be- 
cause its leaves remain attractive to the beetles over a long period. 
Otber kinds of trees may be the most important food elsewhere. Feed- 
ing changes are not abrupt, but gradual, as the various foods become 
available. 
The lamellicorns’ adaptability to a large number of food conditions, 
and to changing conditions in foods is undoubtedly very important. 
For the more variable feeders, of which Phyllophaga drake is an out- 
standing example, this adaptation makes possible a large supply of 
food at all times, and a more certain supply during seasons unfavor- 
able to one or more plants. As one probable result, P. drakei is the 
most abundant species of the important leaf chafers in the Lake 
States. Further study will likely result in the determination of other 
very successful species over given areas. 
The food preferences of the lamellicorns deserve careful study. 
From published records, it appears that collectors may have been 
inexact in their use of the term “host plant.” For example, four 
seasons of study on the Huron National Forest failed to disclose a 
single instance in which Phyllophaga beetles took coniferous leaves 
as food, either as determined by nightly collections from food plants 
