17 
July 6 to 9, 1897. From these there had issued up to August 2 the 
following parasites: 
Specimens. 
Stat 2 aetna. ee ga eal a AE ley re een Ae 220 
SLU MIEIONUO ME Dae ee es a oS cae de cape Pde Sard wae kone 355 
rere mn Olan I BONTEE, Sart sf 35) J. 2 os eo OS las Seto ke a Be ae as 464 
Sea Et AMY Sareea ee he cepa as ee Rs elie Lis kl eee ee ee sa 13 
RENAUD ca ts! SS he IES Fs ben MSL 2 oo 8s aya deed ep SER aoe e 4 
ROS ER De Si rk ke in ne eel a pee ae ee 5 
ME RIRIAN SeE e  e S olt  s S euha als od a hae Sew ani ge ee dd1 
0 A Oe ai SiO rap Pe a le ee ee Rtg ee 3 
Prorsenys bouchesnus 2: 2.2.22 2 lk e esa 10 
ie Re Aa ee Ne Po ee a ais nh o's - ae eee Emde oe 1, 665 
Of these it will be noticed that more than two-thirds (1,101) were 
dipterous, while the previous summer dipterous parasites had consti- 
tuted only about one-twentieth of the number reared. 
From the 5,000 cocoons there issued also 521 male moths and 764 
female moths; 146 of the caterpillars or chrysalids died from a disease 
which we have for convenience called “ black rot,” and 33 from another 
disease which for the same reason we have called ‘red rot.” 
In percentages the result may be expressed as follows: 
Per cent. 
ES Pe Uo: Pay 2 ee ee 2 ee eee ea! A | 
eS PTS Sg ET 9a Spe ao Aa aes ea Set ee ee an 22.02 
I MTEC GERM SS yarn hen Wo ne SaaS wis 9 oie mote n sw tes case 11, 02 
I oS be ee ek A a ae i nae oes Sonn aen ance asda am 3. 58 
televise ne hie see tee Sel eS Sa AE 13st ik Ske sia 24 3-98 3-6 5g. 57. 69 
This leaves about 2,000 chrysalids dead from causes not yet ascer- 
tained. From careful examination of a small proportion of them it 
seems probable that from 400 to 500 have been killed by parasites 
which have died without emerging. There still remain also about 200 
dipterous puparia in the rearing cages, from which the adults may still 
emerge. That the majority of the remainder have died from disease 
seems probable. The mortality ratio was, therefore, 79 per cent, as 
against 98.2 per cent at a corresponding time last year; and, while last 
year hymenopterous parasites were responsible for nearly the whole of 
the mortality, this year they brought about not more than 15 per cent. 
These additional observations only accentuate the extraordinary fea- 
tures of the parasitism of this lepidopterous insect. The multiplicity 
of factors upon which its increase and decrease depend and the impor- 
tant interrelations of the species concerned are astonishing to one who 
has not especially studied this phase of insect life. 
In commenting upon the preceding paper, Mr. Poulton spoke of its 
great interest from a biological standpoint, and made inquiry concern- 
ing the oviposition of the secondary parasites. As an explanation of 
5441—No. 9 2 
