Ea-I(ibitioits, c^-c. 



Mr. M'Lacblan called attention to a notice by Prof. F. A. Forel, 

 published in the ' Proces-Verbaux de la Societe Vaudoise des Sciences 

 Naturelles' (seance du 5 Decerabre, 1877), concerning certain sculptured 

 markings on cretaceous pebbles from the shores of Lac Leman. Various 

 theories had been propounded to explain the cause of those markings, such 

 as the action of Algae, Mollusca, &c. Prof. Forel had, however, come to 

 the conclusion that they were mainly due to the action of larvas 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'Lacblan had received from Prof. Forel, through Capt. Marshall 

 Hall, certain of these larvae 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 larvae, which apparently were those of the genus 

 Philo2)otamus in the family Hy dropsy chida. 



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 larvae, 

 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 themselves had been directly 

 acted upon by the larvae. 



Papers read, dc. 



Mr. J. S. Baly connnunicated a paper entitled " An Attempt to point 

 out the Differential Characters of some closely-allied Species of Chrysomela, 

 chiefly those contained in Suffrian's llth 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 

 Cetoniidm" and "On some unusual Monstrous Insects." 



Mr. W. L. Distant read a paper entitled " Contributions to our 

 Knowledge of the Hemipterous Fauna of Madagascar." 



Sir Sidney Saunders communicated the following notes from M. Jules 

 Lichtenstein, of Montpellier, describing the metamorphoses of the blister- 

 beetle, which, after repeated failures for many years, he had recently 

 succeeded in rearing from the egg. The most remarkable circumstance 

 connected with these transformations or " hypermetamorphosis " (as in 



