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BULLETIN 1429, U. S. DEPARTMENT OF AGRICULTURE 
TIPHIA VERNALIS Eohwer 
GENERAL OBSERVATIONS 
Tiphia vernalis is a Chosen species which has for its normal host 
Popillia castanoptera. It was found by the junior writer in May, 
1922. In establishing the value of this and all other Chosen scoliids, 
they were ferst tested out on larvae of P. japonica which were taken 
from Japan to Chosen for that purpose. If they readily accepted 
the Japanese Popillia, they were considered of economic importance 
and their study and rearing were continued. 
In the studies of several species of Tiphia it was found that the 
group as a whole tends to be limited to a host genus rather than to a 
single species. TipMa vernalis will accept grubs of P. atrocoerulea, 
but as a rule this host is physiologically unfit, being too near the 
pupal period to be readily parasitized. On the other hand, P. 
japonica is taken early enough to be suitable. In captivity this 
Tiphia has been reared on four species of Popillia. 
In the spring of 1922 a few indi- 
viduals were reared on P. japonica 
(fig. 28), but in 1923 this work was 
undertaken on a large scale with 
native hosts. Hundreds of females 
were collected in the field and 
brought to the laboratory for ovi- 
position and rearing of larvae. The 
same rearing methods were used as 
for the preceding species. At times 
as many as 450 females were on 
hand for this purpose. From a total 
of 5,785 eggs obtained at Suigen in 
Fig. 28.— Larva of Popillia japonica parasitized moo o ocn ,>~„~~~~ , X^4-^:-^^A 
by Tiphia vernalis 1923, 2,350 cocoons were obtained. 
LIFE HISTORY AND HABITS 
The adults of TipMa vernalis are found in the field from May 5 to 
June 14, with a maximum abundance from May 19 to 25. Feeding 
takes place largely upon honeydew produced by aphides on pine, 
oak, and chestnut. The females are most abundant on chestnut 
foliage from 9.30 to 11.30 a. m. on warm, bright mornings. A low 
temperature tends markedly to slacken activity. 
Although the adults seem to be very local in distribution, the parasi- 
tism of Popillia grubs in regions where the wasps were not abundant 
indicates that the species is more generally distributed than is evi- 
denced by the presence of the adults alone. 
Tiphia vernalis, although not of prime importance, is well worth 
introduction. Its occurrence in the spring is timely for Popillia 
in America, and if introduced with the preceding species would 
form the practical equivalent of a two-brooded species. On June 5, 
1923, a count of 100 field-collected grubs gave a 10 per cent para- 
sitism by vernalis. 
The egg-laying habits of this species are similar to those of Tiphia 
popilliavora, except that the eggs are placed in the suture between 
the third thoracic and first abdominal segments on either side of the 
median ventral line (fig. 26), and with the anterior pole directed 
