310 
THE PRINCIPLES OP 
Part II. 
Walsh, who informed me of this statement, says that with P. 
turnus this is certainly the case. In South Africa, Mr. R. Trimen 
found the males in excess in 19 species ; 68 and in one of these, 
which swarms in open places, he estimated the number of males as 
fifty to one female. With another species, in which the males are 
numerous in certain localities, he collected during seven years only 
five females. In the island of Bourbon, M. Maillard states that 
the males of one species of Papilio are twenty times as numerous 
as the females. 69 Mr. Trimen informs me that as far as he has 
himself seen, or heard from others, it is rare for the females of any 
butterfly to exceed in number the males ; but this is perhaps the 
case with three South African species. Mr. Wallace 60 states that 
the females of Ornithoptera croesus, in the Malay archipelago, are 
more common and more easily caught than the males'; but this is 
a rare butterfly. I may here add, that in Hyperythra, a genus of 
moths, Guenee says, that from four to five females are sent in 
collections from India for one male. 
When this subject of the proportional numbers of the sexes of 
insects was brought before the Entomological Society, 61 it was 
generally admitted that the males of most Lepidoptera, in the 
adult or imago state, are caught in greater numbers than the 
females ; but this fact was attributed by various observers to the 
more retiring habits of the females, and to the males emerging 
earlier from the cocoon. This latter circumstance is well known to 
occur with most Lepidoptera, as well as with other insects. So 
that, as M. Personnat remarks, the males of the domesticated 
Bombyx Yamamai, are lost at the beginning of the season, and 
the females at the end, from the want of mates. 62 I cannot how- 
ever persuade myself that these causes suffice to explain the great 
excess of males in the cases, above given, of butterflies which are 
extremely common in their native countries. Mr. Stainton, who 
has paid such close attention during many years to the smaller 
moths, informs me that when he collected them in the imago state, 
he thought that the males were ten times as numerous as the 
females, but that since he has reared them on a large scale from the 
caterpillar state, he is convinced that the females are the most 
58 Four of these cases are given by Mr. Trimen in his 4 Rhopalocera 
Africa Australis.’ 
50 Quoted by Trimen, 4 Transact. Ent. Soc.’ vol. v. part iv. 1866, p. 330. 
60 4 Transact. Linn. Soc.’ vol. xxv. p. 37. 
61 4 Proc. Entomolog. Soc.’ Feb. 17th, 1868. 
62 Quoted by Dr. Wallace in 4 Proc. Ent. Soc.’ 3rd series, vol. v. 1867, 
p. 487. 
