496 
Journal of Agricultural Research 
Vol. VII, No. ii 
latter entirely disappears the larva begins to feed on the cotyledons, 
eating out a pit on one edge or one side and ultimately devouring the 
last traces of the embryo. 
Duration of instars and feeding period. —The two seasons during 
which observations on the life history of the apple-seed chalcid were 
made were quite different, and the development of the larvae was con¬ 
sequently quite different in point of time required. The summer of 1915 
was unusually cold, and the larvae required about a week longer to com¬ 
plete their development than those of 1914. 
The observations of 1914 were complicated and rendered somewhat diffi¬ 
cult of interpretation because of an unexpected infestation from natural 
sources. The presence of the species 
in the locality was not discovered un¬ 
til too late to escape the infestation 
from that source. However, the nat¬ 
ural infestation was, as a rule, either 
considerably earlier or considerably 
later than that in the cages, and some 
information of value can be secured 
from the data obtained. 
In 1915 these difficulties were elim¬ 
inated by the expedient of bagging 
all fruit to be used in the work both before and after it was exposed to 
the attack of the insects in the cages. 
In 1914 the first individual of each instar was found about four days 
after the first of the immediately preceding instar, all transformations 
from one instar to the next taking place within a period of about a 
week. In about 45 days from oviposition practically all the larvae had 
finished feeding. Table I gives the data on the development of the 
seed chalcid during 1914. From this table are excluded all individuals 
the presence of which was obviously due to natural infestation. 
Fig. 7 .—Sytiiomaspis druparum: Mouth parts of 
full-grown larva, c, Labrum; b, mandible; c, 
maxilla; d, maxillary palpus; e, labium; /, la¬ 
bial palpus. Highly magnified. (Original.) 
Table I. —Development of Syntomaspis druparum at North East, Pa., in IQ14 
Period from infestation to 
examination. 
Date of 
infestation. 
Date of 
examina¬ 
tion. 
Stages of insect found. 
Eggs. 
First Second 
larval, larval. 
Third 
larval. 
Fourth 
larval. 
Fifth 
larval. 
Days. 
3—4.,.„ „. 
June 20-21.. 
July 3-4.... 
June 18-19. • 
June 25 .. 
June 24 
July 8 
June 24 
July 1 
July 8 
July is 
July 1 
...do. 
6 
3 
4 
17 
3 
2 
1 
4-5. 
S-6 . 
6. 
2 . . 
7. 
July a . 
July 9. 
O *.■ 
A . 
July 1. ... 
*T * * * * * * * * 
2. 
. 
8... 
jime 23. 
J * * .. 
6. 
8-9. 
July 7. 
July is 
July 8 
July 15 
July 16 
12 ... 
June 29-30.. 
July 6. 
3 . . 
July 7. 
' 4 . 
