ey) 
from races by preferential syngamy is of such high import- 
ance that we may confidently hope that the attention here 
directed to the question, and especially the quotation of 
Darwin’s letters to Bates, may lead to that “exact and 
prolonged observation,” accompanied by careful records, with- 
out which a safe decision cannot be reached. In the 
meantime the decided impressions of two such naturalists as 
H. W. Bates in South America and Roland Trimen in South 
Africa render it in every way probable that the conclusion 
will be established on a firm foundation.* 
It is also possible that asyngamy may be brought about by 
the breaking of what we may call “a syngamic chain.” In the 
case of large and widely-distributed interbreeding communities, 
it is an open question whether syngamy would freely take 
place between the most distant of the outlying sections if 
directly brought into contact, and whether, even if syngamy 
prevailed, there would be any diminution in fertility. 
Limnas chrysippus, perhaps the commonest butterfly in the 
world, forms a probably continuous syngamic chain stretching 
from the Cape of Good Hope at least as far as Southern China. 
It is even reported from Japan. The far Eastern forms are 
readily distinguishable by the greater size of a single white 
spot, giving quite a different appearance to the fore-wing. 
If pup or eggs were transferred from Hong-Kong or Macao 
to South Africa, would the perfect butterflies freely interbreed 
* Dr. T. A. Chapman sends me the following interesting and suggestive 
note :— 
“I met lately with a curious instance that deserves following up, of 
some bearing on the question of selective mating of varieties, 
“*T saw some broods of P. phlwas lately that differed from each other, 
but each brood was remarkably uniform. There were three broods, all 
bred in the same conditions, in a greenhouse (by Mr. Carpenter of 
Leatherhead). It seems difficult to explain this, unless both parents of 
each brood were very nearly identical. 
“Mr. Frohawk, who has bred the species largely, tells me he has 
noticed similar facts. 
“When I bred Acronycta tridens and psi largely, some fifteen or more 
years ago, I noticed that each brood had its own pairs, and suggested that 
tridens was now trying to break up into separate species just as some 
ancestor split into psi, tridens and cuspis. 
*‘ Another fact I observed in Acronycta rather bears on the other side 
of the question. Of 4. strigosa I reared a large brood, which paired 
readily and frequently together, but no eggs were laid. I then got some 
captured males, which paired with equal readiness with the bred females, 
and as a result obtained plenty of fertile eggs.” 
