26 
BULLETIN 1429, U. S. DEPARTMENT OF AGRICULTURE 
DEXIA VENTRALIS Aldrich 
Dexiaventralis (fig. 22) is the most common of the dexiids of Chosen, 
and was first found shortly after the commencement of investiga- 
tions in that country in late May, 1922. Experiments with it upon 
grubs of Popillia japonica indicated that it would develop satisfac- 
torily in that host, and, consequently, further studies were made upon 
its biology. 
In distribution, this species covers all of Chosen and also the plains 
area of Manchuria, which latter was scouted during the summer of 
Fig. 22.— Dexia ventralis, female 
1923; but it is most common in the central portions of the former 
country. It is also recorded from the Malayan region. Practically 
all of the breeding and life-history work was done at Suigen, Chosen. 
No shipments of this species have been made to America as jet on 
account of the necessity of first determining certain factors in its 
biology which have an important bearing upon its potential value 
under the changed conditions. These various factors will be dis- 
cussed in detail later. The earlier observations indicated only one 
generation per year, arid since the adults appeared in late May and 
disappeared within one month it was naturally concluded that the 
