The caterpillar was well known to entomologists in this country as far back as 1758, when, in May, four were obtained from sallow at Brentwood in Essex. It usually occurs on sallow, but an instance is recorded of it refusing to eat this plant; it would probably have starved if willow, upon which it fed up, had not been substituted. A full-grown caterpillar was on one occasion found at Raindene in Sussex on poplar, which is a well-known food of the species on the Continent. Now and then a full-grown caterpillar has been met with in October, and Buckler reared two in the autumn from the egg almost to the chrysalis stage, but they died before the change was effected.
As befits his rank, the Emperor has lofty habits, and after quitting the clump of sallow bushes, among which its transformations from egg to the perfect insect were effected, it resorts to the oak trees, around which it flies in July, and, when not so engaged, rests on a leaf of the higher branches. To capture the butterfly, when seen at such times, is not altogether an easy matter, as for the purpose the net must be affixed to the end of a pole about 14 or 15 feet in length. The insect's rather depraved taste for the juices of animal matter, in a somewhat advanced stage of decay, is a fact well known to the professional collector and others who have taken advantage of it to the monarch's destruction. This method of attracting a butterfly for the purpose of capture is, however, not exactly to be commended. It surely is a greater pleasure to show one's friends a single specimen that has been captured by dexterity with the net, than to exhibit fifty that were secured by a device which is not only unsavoury, but unsportsmanlike. The female, however, is not to be allured; she must be sought among the sallows, and when seen is not easy to net, as she skims away over the tops of the bushes and is difficult to follow.
Larger Image
Pl. 26.
Brimstone Butterfly.
1, 3 male; 2, 4 female.