PROCEEDINGS OF SCIENTIFIC SOCIETIES 317 
Entomonocicat Society or Loxpon. 
June 4, 1879.—H. W. Bates, F.L.S., F.Z.8., Vice-President, in the 
chair. 
Donations to the Library were announced, and thanks voted to donors. 
Mr. J. Walhouse, F.R.A.S., of 9, Randolph Crescent, Maida Vale, was 
ballotted for and elected an Ordinary Member. Senor Antonio Augusto de 
Carvatho Monteiro, 72, Rua do Alecrion, Lisbon, was ballotted for and 
elected a Foreign Member. Mr. GC. H. Goodman, of Kearsbrook Lodge, 
Lesness Heath, Kent, was ballotted for and elected a Subscriber. 
Mr. M‘Lachlan called attention to a notice by Prof. F. A. Forel, 
published in the ‘ Procés-Verbaux de la Societé Vaudoise des Sciences 
Naturelles’ (séance du 5 Decembre, 1877), concerning certain sculptured 
markings on cretaceous pebbles from the shores of Lac Léman. Various 
theories had been propounded to explain the cause of those markings, such 
as the action of Alge, Mollusca, &. Prof. Forel had, however, come to 
‘the conclusion that they were mainly due to the action of larvee of 
Trichoptera, which formed galleries over the surface, and there were 
larger and deeper depressions in the places where the cases were fixed, 
Mr. M‘Lachlan had received from Prof. Forel, through Capt. Marshall 
Hall, certain of these larve in alcohol, and two plaster casts of small blocks 
(exhibited), one of Jurassic limestone, the other of ordinary white chalk, the 
latter being one of several placed in the lake by Prof. Forel on the 12th 
March, and taken out on the 26th November following, and on which he 
had scratched his initials: these scratches had been deepened in some 
places by the action of the larvee, which apparently were those of the genus 
Philopotamus in the family Hydropsychide. 
Mr. Meldola suggested that the depressions in the pieces of chalk and 
limestone might have been produced by the solvent action of the water 
charged with carbonic acid, which issued from the galleries of the larve, 
a circulation of oxygenated water being necessary for their respiration, and 
after being used for this purpose the effluent water would naturally contain 
more carbonic acid than before its entry into the galleries; but this 
explanation would not hold good if the casts themselyes had been directly 
acted upon by the larve. 
Mr. J. S. Baly communicated a paper entitled “ An Attempt to point 
out the Differential Characters of some closely-allied Species of Chrysomela, 
chiefly those contained in Suffrian’s 11th group; also Descriptions of some 
hitherto uncharacterised forms belonging to the same and other Genera of 
the Family.” 
Prof. Westwood communicated two papers, entitled “ A Decade of new 
Cetoniide,” and “On some unusual Monstrous Insects.” 
Mr. W. L. Distant read a paper entitled “Contributions to our 
Knowledge of the Hemipterous Fauna of Madagascar.” 
