( xviii ) 



Mr. C. O. Waterhouse read some " Descriptions of new Coleoptera from 

 Madai^ascar belonging to the Melolonthidm." Thirteen new species and 

 one new genus [Eutrichesis) were characterised. 



September 6, 1883. 



H. T. Stainton,. Esq., F.R.S., &c., President, in the chair. 



Donations to the Library were announced, and thanks voted to the 

 respective donors. 



Exhibitions, dc. 



Mr. R. M'Lachlan exhibited a box containing 500 or 600 Neuroptera 

 and Trichoptera, being a portion of his captures during a tour in Switzer- 

 land (chiefly in the Canton Valais and vicinity of the St. Gothard) and 

 North Italy (chiefly in the Val Anzasca) in July last. There were many 

 interesting forms, including some that were new. The genus Rhyacophila 

 was represented by twelve species, including numerous examples of a large 

 new species from Val Anzasca and Val Cannobina, and a number of 

 jR. Meijerl, M'Lach. (hitherto known from a single imperfect example), 

 from the same localities. There were also curious new forms of minute 

 Conioptenjcjida, amongst others a nearly black species from the Val 

 Levantina, and a spotted or blotched species from the Val d'Anniviers. 



Mr. M'Lachlan also exhibited a mass of the so-called " Indusial Lime- 

 stone" of Auvergne, given to him by Mr. H. W. Jackson, M.R.O.S., F.G.S., 

 who found it above Romagnat, near Clermont Ferrand. This curious 

 formation is well known to be made up of the cemented masses of shell- 

 bearing caddis-worm cases lying together in an irregular manner. He read 

 an extract from Lyell's ' Elements of Geology' (5th ed. pp. 201-2, 1855), in 

 which was detailed an account of the position of these indusial beds, and an 

 explanation of the probable manner in which they were formed. Lyell 

 assigned the formation to the Upper Erocene period, and there appeared to 

 be no doubt it originated before the extinction of the volcanoes of the region, 

 because beds of lava, &c., overlie the indusial beds. In connection with 

 this Mr. M'Lachlan remarked that the caddis-cases must have belonged to 

 insects of the family Limnojyhilida:, and probably to Limnophilus itself, but 

 it so happened that, although fossil Trichoptera occurred in abundance in 

 even older formations, the LimnophiUdd' were absent or nearly so (so far as 

 has been recorded), and yet from their strong wing-nervures they appeared 

 the most suitable for preservation in a fossil state. liOoking at this formation 

 fi'om an entomological rather tiian a geological point of view, Mr. M'Lachlan 



