14 
from this rivalry based upon erroneous instinct, as well as from the 
attacks of hyperparasites. Such mistakes are of course uch more 
likely to oecur during such times of extraordinary multiplication than 
when the species are normally abundant. 
During the entire series of observations careful records were kept of 
all specimens of Pimpla reared. The following table indicates numbers 
and dates: 
Num- Num- Rig) | Num- : | Num- 
Date. ner Date. Were Date. we Date. ina 
1895. 1895 1896 
sept. 12----.----- A COYems, OS caeress Gr Mars 192 eee 23 | July 2 
eieeosocoba 15 i ae 5 yA | ee ta 21 23 
(aie as: 12 ie eae 7 Cy Pen ae tee | 6 29 
1OeseSece es. 6 1D se Sains 2 2a25 i 224 
Wi eee eee OfeNov.. Ge... o-2256 | 2 py. a eee 2 50 
Ls coe ce- tee 12 Gee eae ator 3 PA eee pease 14 82 
LG ete tere 22 Wee ee ie 2 71 (Ree 2 100 
1 (es ce eae 55 1 he apy eo 1 30. - Uf 60 
he ososeooot 96 Dee. + hiss... 222. 1 i} ee A 5) 60 
eS Cee 90 1896. Ati a lane ame 1 100 
erase rslaiaiste AC alt) ihe eee ee = ae 1 De 2 eee: 3 50 
OS eee 20) I) War! Soame--ee-= 2 ieee es cas 2 50 
2 ee Oe 20 aes ea 1 G26 225 eee2 3 20 
inp ees 7 Th ee ls IE 2 ia Saacrane 1 12 
DR Ree sec ees 4 i Pee 6 Qe cept 1 10 
OUirias weietaerc 5 O ee ciecs 1] LO ee ae 5 3 
OCUsmale e-em ] Bt aetegtineny te 9 ible aetio os 1 4 
ha SE OOOROS 4 Ve ee ee 18 Ld tce eee ae 4 é 1 
BARE AeaSed| 3 Ae eeerse 8 I sa5dnc- Bh) Ala a reieleeiarale 1 
| ete 12 LV eee 9 163.6 fst ces 1 LO Risse cates 2 
ear nae 7 1Gxseecces 7 182. jeeeee 5 26% -scieeee il 
Ht (ee ee 5 Ly (eee 19 20... seeterete 19 5 
eee eee 8 bois eee ae 14 73 Ee Zz Mopalleeee. 1, 659 
It will be observed that the periods of greatest abundance were from 
September 12 to 26, 1895; from March 9 to 26, 1896; from April 10 to 
20, 1896, and from July 10 to 25, 1896. 
The percentage of parasitism by this species was indicated rather 
plainly by four series of experiments. 
irom 100 cocoons collected September 
10, 1895, there issued 38 adults; from 
about 500 cocoons collected August 23, 
there issued 300 specimens; from about 
300 cocoons collected August 21, there 
issued 172; from 604 cocoons collected 
between June 30 and- July 8, 1896, 
there issued 729. 
ae We have not previously stated defi- 
Fic. 4.—Pimpla inquisitor : a, mass of male : th : . 
cocoons; &, do., cross-aectioned; ¢, erose Ditely the number of specimens of the 
section of largest cocoon mass found; d, parasites nourished by a single Orgyia. 
ae of female ¢ocoons—nat. size (orizi- "he numberim SUMMer Varies arom no 
10, with perhaps an average of 3 or 4. 
This number refers to the large well nourished larvie, mainly females. In 
the late autumn more are found. Ten to fifteen Pimpla cocoons in a single 
Orgyia cocoon are not at all unusual at this time of the year, while from 
a single Orgyia cocoon collected by My. Busck in September, 1896, were 
reared no less than 25 Pimplas, all of which were males. This particu- 
lar Pimpla cocoon mass was cross-sectioned, and is illustrated at fig. 4e. 
