13 
WEDNESDAY, MARCH 14th, 1888. 
OBSERVATIONS IN MOTH BREEDING 
FOR PEDIGREE PURPOSES. 
Mr. F. MERRIFIELD. 
These were observations made in the course of a series of 
experiments tried at the instance of Mr. Francis Galton in 
_ Pedigree Moth-breeding. Mr. Merrifield said that, having 
- obtained plenty of living specimens of Selenia illunaria 
_ (“Early Thorn Moth”) in the spring, his experiments with 
_ that species were more advanced than with Selenia illustraria 
(“Purple Thorn Moth”). From eggs of ilunaria laid by 
moths taken in the spring he had reared a second generation 
_ fed on sleeved birch trees, the moths emerging in July. From 
these he had made a selection of long-winged (A), medium- 
_ winged (M), and short-winged (Z) pairs, and from each of these 
pairs he had batches of pup numbering from 60 to 100, now 
_hybernating. Besides the insects thus reared under natural 
conditions, he had reared some which were kept during all their 
"stages in an artificial temperature averaging a little under 80° 
Fahr. In this way he had obtained five successive generations, 
the last of them being the sixth generation of the year, counting 
a generation as beginning with the egg (the moths caught in the 
spring reckoning as belonging to the first) being now in the egg 
‘stage. The forced second generation was distinctly larger than 
the same generation sleeved, and each successive forced genera- 
4 tion, except the last, which had been brought up under difficulties 
_as to food, and had suffered great mortality, shewed a measurable 
a . erease in size over its predecessor. From the forced second 
generation he had selected A, M, and Z pairs, from each of which 
had reared a number of moths, but the A’s and Z’s in this 
d generation failed to produce fertile eggs, though several 
pairs of each were tried. The M’s produced abundantly, and 
from one of these M pairs he bred 61 moths, from which he had 
again selected A’s, M’s and Z’s, which laid fertile eggs, and from each 
of these pairs he had obtained about 7 or 8 moths, all proving sterile 
