162 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
unimportant, as they caused fatal injury to less than 20 percent of 
experimental seedlings, even when dense populations were tested. It 
appears doubtful that this degree of mortality occurs in the field. The 
genus Polyphylla has not been extensively investigated. 
Of the groups known to be destructive, the Phyllophaga, or June 
beetles, are by far the most important, because of their wide distribu- 
tion, the large number of species, their dense populations, and their 
destructive feeding habits. The other genera listed as injurious occur 
only locally, in more or less scattered populations, and are not of great 
importance in forest management. 
In the Gulf States there is relatively little damage by white grubs, 
as compared with that in forest nurseries in the Appalachians, the 
Piedmont region, the New England, and the Lake States. For a more 
complete treatment of the subject the reader is referred to the following 
authors: Criddle (727) ; Fluke, Graber, and Koch (159, 160) ; Forbes 
(161, 162, 163, 164) ; Hadley and Hawley (206) ; Hawley and Hallock 
(211); and Sweetman (404, 405). Control of these beetles is dis- 
cussed on page 28. 
To enable the reader to understand better the descriptions of the 
various insects, a diagrammatic drawing is presented of a typical 
scarabaeid larva, Popillia japonica Newm. (fig. 38), in which the names 
of many of the parts are given. 
Posterior end Head-front view 
Anal slit T Epicraniat 
Third o \S Ne ty Epicranial 
Legs; Second : ~ arm 
Fi {(y peal 
Prothoracl plate 
sclerotized clopeus 
plate Lobrum 
Three Mandible 
thoracic “P Lower surface 
segments of clypeus and 
labrum to 
show location 
B of Epipharynx 
Distal Sensory eminence 
sclerotized plate F 
Sensillae 
Fixed spines 
Articulated spines | \ [7 oatcoth 
%, 
< BZ 
Saich ys A 
S ese 
SOs ~ Marginal 
SE, striae 
ef CL/ 7 
2 
oO 
za 
— 
StS Y 
Sense cone 
Clypeal 
sclerotized 
plate Epigusta D 
Clypeal sensillae 
Popillia japonica Newm: 
Ficure 38.—Diagrammatic drawings of larva of Popillia japonica with various 
anatomical parts and characters named: A, Lateral view of grub; B, front 
view of head; C, outline of epipharynx (roof of the mouth) ; D, lower surface 
of last segment, showing anus and spines, 
