Cale [xxii-xxili 
showed the usual markings of the species on a cream-coloured 
ground, faintly shot with pinkish or apricot. There was a 
slight smoky shade over the central area of the fore-wing, the 
hind-wings were yellowish-grey, the thorax yellowish-brown, 
the abdomen apricot-coloured with a dorsal chain of dark 
tufts. Mr. C. G. Barrett had examined the specimen, and 
pronounced it probably unique. Sir George Hampson had 
also seen it, and pointed out that it was provided with the 
spur on the anterior tibia, which is characteristic of J/. brassicx 
among the allied European species. 
Papers, ete. 
The PreEsIDENT, Professor Povuiron, read the following 
observations on the gregarious hibernation of certain 
Californian insects, communicated to him by Professor 
Vernon L. Kellog, of the Leland Stanford Junior University, 
California. 
‘In reading in Marshall and Poulton, Trans. Ent. Soc. 
Lond. 1902, your references to gregariousness in hibernating 
and migrating insects, I was reminded of two conspicuous 
examples of gregarious hibernation which we observe here every 
winter, The Monarch Butterfly, Anosia plexippus, gathers 
each winter in thousands in a small forest of pine trees on 
Point Pinos peninsula on the Bay of Monterey. Sometimes 
these butterflies will gather in a single tree in great clusters 
and festoons ; other winters they will not be quite so compactly 
massed, but will be spread over a few acres of forest. The 
Asclepias, the food-plant of this insect, does not grow, at least 
in any abundance, on this peninsula, but does grow on another 
promontory about fifty miles north, and there I have found 
the larve and pup in great numbers. 
** You are aware that our winter here is very mild; there 
are bright warm days all through it, and these butterflies do 
not by any means remain immovable during their hibernation. 
Flowers are blossoming all through the winter in the little 
village on Point Pinos, and the butterflies may be seen 
fluttering about at these flowers on any bright day in the 
winter. Nevertheless this is true hibernation and conspicu- 
ously gregarious in character. This butterfly is one which 
