174 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
slender and never exceed 15 mm. in length. Their food, presumably, 
is the roots of plants. In heavy concentration and under experimental 
conclitions, they fed lghtly on the rootlets of pine seedlings. As 
practically none of the seedlings were killed, it appears that the: species 
may be relativ ely unimportant in forest plantations. Very large 
numbers in nurseries may cause more or less injury. 
The beetles of the genus Serica Mach. resemble the June beetles 
more than any other of the lamellicorn group, except for the size and 
ridged wing covers of the latter. The Serica beetles are much smaller, 
little more than one-fourth the size of most Phyllophaga. WS. sericea 
(IIL. ) is an abundant, iridescent, purphsh-brown, hairy species. S. 
vespertina (Gyll.) and 8. intermirta Blatch. are also very common, 
but are smooth, and dark brown and light brown, respectively. A 
number of other species occur in the Eastern States. It appears that 
this genus is less abundant in Minnesota than in Michigan, but 8, 
sericea has been observed in large numbers on the flowers of June- 
berry in Minnesota. 
As far as known, all species feed on hardwood leaves. The eastern 
species are essentially nocturnal, though feeding and flying individ- 
uals have often been observed during ‘the interval between sundown 
and dark. Adults are most abundant in June, but the period of 
emergence, in the latitude of the Huron National Forest, is from the 
middle of May to the middle of August. In pure hardwood stands, 
the several species may be so abundant as to cause some defoliation, and 
on such areas they may be collected at night by the hundreds. Larval 
populations are heaviest in such places. 
The larvae are very active, but are small, probably never exceeding 
15 or 18 mm. in length. Heavy concentrations, under exper imental 
conditions, fed appreciably on coniferous roots, killing between 15 
and 20 percent of the seedlings used in the experiments. In planta- 
tions it 1s very doubtful that serious loss by Serica grubs would occur, 
but such losses may occur in heavily infested nurseries. Like Diplo- 
taxis, the Serica grubs prune the roots rather than cut off the taproot 
near the ground surface. 
The group has a 2-to 3-year life cycle. In the latitude of central 
Michigan the insects overwinter in both the larval and adult stages. 
Pupation occurs from July into September, and the adults appear 
before the hibernation period begins. Adults of some species are not 
particularly attracted to hghts, “but others have been taken only in 
this manner. 
One species of the exotic genus Autoserica Brenske, the Asiatic 
garden beetle (A. castanea (Arrow) ), has been intr oduced into this 
country from Asia and was first collected in New Jersey in 1922. It 
has now spread to numerous localities in the Atlantic Seaboard States. 
More of a garden than a forest insect, it is included here because of 
the very close morphological similarity between Autoserica and Serica 
adults and larvae. Owing to its apparent preference for garden crops, 
it May never prove destructive to forest plantations, but because of 
its association with cultivated soil and the heavy larval concentrations 
known to occur, it may become a problem in eastern forest nurseries. 
The fact that it may produce two generations a year may prove a factor 
in its capacity for injury (Haw ley and Hallock, 277). 
