( Ixxxii ) 



definite adaptation of instinct to produce the result. Tlie 

 cocoon had a very dense appearance, but it would be satis- 

 factory to examine it before the extrusion of the larval 

 skin and to watch the larva when spinning. It was by no 

 means uncommon for procryptic colouring and habits to be 

 combined with an aposematic second line of defence. He 

 suggested that the use of the old larval skin might be com- 

 pared with the still more elaborate instinct described by 

 Portchinsky in a species of Lina (Melasoma) — he believed 

 L. tremulae, F. The larva of this Chi*ysomelid beetle, when 

 disturbed, extruded a spherule of milk-white fluid at the 

 aperture of each gland-duct opening on the skin, and when 

 disturbance ceased the fluid was again withdrawn into the 

 body. Professor Poulton said that he had witnessed this 

 procedure in the larva of a species of Lina at Lake Louise, 

 in the Canadian Rockies, in the autumn of 1897, and had 

 found it to be precisely as described by the Russian 

 naturalist. Portchinsky stated that a store of the same 

 fluid is contained in the old larval skin after pupation and 

 that, when the pupa is irritated, it "sits up" and brings 

 pressure to bear on the skin which still envelops its posterior 

 segments. This pressure causes the fluid to appear at the old 

 apertures, to be presently withdrawn by the recovery in the 

 shape of the skin when the pupa sits down again. Professor 

 Poulton said that he owed the translation of this observation 

 from the monogiaph of the distinguished Russian naturalist 

 to the late Professor W. R. Morfill, of Oxford. 



Dr. T. A, Chapman remarked that the hairs covering the 

 eggs of Porthetria dispar are also urticating. He also observed 

 that there are other species of moths which extrude the larval 

 skin, but in these cases it was from flimsy cocoons. Mr. J. H. 

 DuRRANT also gave instances of this fact. 



The warning colours of the Hypsid moth " Callioratis " 



PACTOLICUS, BuTL., IN ALL ITS STAGES. ProfeSSOr PoULTON 



exhibited the larvae, pupae and imagines of '^ pactolicus," sent 

 by Dr. G. D. H. Carpenter. Two species belonging to the genus 

 Callioratis had been recently recognised as Geometridae, and 

 had carried off the genus into this family, leaving the true 

 Hypsidae, pactolicus and its allies, at present without a generic 



