Prosena si'berita F.-,^This parasite of Japanese Tseetle larvae has been re- 
leased in n-ura'bers totaling 12,364 individuals, distributed in v/\rying numbers in 
5 colonies between 1923 and 1930* Only 1 colony in the Moores town, N, J,, aioa 
is known to bo established* No recent colonization of this species has been 'under- 
taken, The species does not increase in sufficient numbers to be of oconoraic 
importance. The inability of Pros ena to increase its numbers is due largely to 
the fact that its adult stage, is numerous duri;^g, the flight period of its host, 
consequently the scarcity of beetle larvae at this time is unfavorable. In Japan 
this parasite is most nmerous in areas where Poplllia has a partial 2-year life 
cycle, but so far within the area now occupied by the beetle in the United States, 
the occurrence of a 2-year cycle is rate and so localized as to be of little bene- 
fit in increasing the numbers of this parasite, 
Gentoter clnerea Ald,^ This Japanoso fly is a parasite of the ndult stage 
of the Japanese beetle. It has been extensively introduced and from 1922 through 
1933 more than 70,000 flies have been li'bo. rated in varying numbers in 23 colonies, 
13 of which have been recorded .as established. One colony was libor.ated in 1938 
in Washington, D. C, Surveys in .1336 indiq.ate ,thqt the qpecies -has. spread over 
500 square miles in Hew Jersey and .Pennsylvania, The species is not synchronized 
with the bulk of its host,- generally appearing about 2 weeks too early, Rolease- 
ments at Keene, H. H. , in 1936 wore tests to determine whether in more northern 
areas proper synchronization would take place j however, limited observations at 
Keene in 1938 seem to indicate that there also the. species is too early to meet 
the greatest number of beetles. Studies .are now being started on this species 
in southern areas. 
Table 1,— Colony distribution of Qenteter cinerea 
State 
: Colonies^ 
: liberated 
_ . . ;in 1922-38 
;Colonios 
t recovered 
tin 1Q38 
Connecticut 
.. . : Number 
3 
: Number 
: 2 
: 4 
New J ars ev ....... 
Pennsylvania 
New Hampshire . . . . 
i 1 
: 1 
Washington, D. C. 
0 
Total 
; lu 
Tiphia vernalis Roh,- .KThi8 is the most important por.asite of the Japanese 
beetle. The species has been extensively colonized, the present total colonies 
nurabering 1,127, of which 316 were. placed in the field in the spring of 1938, All 
material now used for colonization purposes is field-collected from older colonies. 
Paras Itizat ion of Japfinese beetle grubs by this species ranges from 10 to 60 per- 
cent, vaty^ing according to locality and abundance of host. In 193S there were 300 
colonies released in Maryland, distributed as follows: Cecil County, 179; Kent 
Cmmt/, 40; Harford County, 39* Baltimore County, 38; Wicomico County, 2; Somerset 
County, 1; Worcester County, 1, This number was large enough to permit close place- 
ment of the colonies thron^out the zone of intense beetle infestation,' and also 
to colonize other areas sufficiently infested so as to re.asonably assure establish- 
ment of the parasite. In addition, 15 colonies were released in Connocticut, in 
the following counties: Fairfield, 9; Hew Haven, 1; He^^ London, 1; Windliam, IJ and 
Hartford, 3* One large colony of 635 f^waales was liberated at a very favorable spot 
