280 Botanical Society of Edinburgh, 



March 12, 1846.— Dr. Balfour, President, in the Chair. 



Various donations to the library and museum were announced, 

 and thanks voted to the respective donors. 

 The following communications were read : — 



1. "On the altitudinal range of the Mosses in Aberdeenshire," 

 by George Dickie, M.D., Lecturer on Botany in the University and 

 King's College of Aberdeen. (This paper will be published in these 

 Annals and in the Society's Transactions.) 



2. " Remarks on the state of the Sibthorpian Herbarium at Ox- 

 ford, suggested by the announcement of a new edition of the * Flora 

 Graeca,' " by Dr. R. C. Alexander. 



3. " Botanical Excursion in Lower Styria in 1842," by the same. 

 (This paper will be published in these Annals and in the Society's 

 Transactions.) 



A letter from Dr. Bidwell was read, announcing the discovery of 

 Vaccinium macrocarpum near Mold in Flintshire in August last ; and 

 one from Mr. W. A. Stables noticing the discovery of Neottia nidus- 

 avis in Cawdor Woods, Nairnshire. 



Dr. Balfour exhibited specimens of diseases in plants caused by 

 insects ; one of these consisted of peculiar stipitate excrescences on 

 the leaves of a North American tree, concerning which Dr. Balfour 

 read some extracts from a letter which he had received from Mr. 

 Adam White of the British Museum : — 



" The swellings on the leaves of the plant seem to be caused by 

 some species of Aphis ; one kind is very hurtful to the peach-tree, 

 but attacks the leaves in a different way from the insect on your 

 specimen. Dr. Harris, in his admirable work * On the insects of 

 Massachusetts injurious to vegetation,' speaks of some Aphides, ' the 

 punctures of which affect plants in a most singular manner, pro- 

 ducing warts or swellings, which are sometimes solid and sometimes 

 hollow, and contain in their interior a swarm of lice, the descendants 

 of a single individual, whose punctures were the original cause of 

 the tumour. I have seen reddish tumours of this kind as big as a 

 pigeon's egg growing upon leaves, to which they were attached by 

 a slender neck, and containing thousands of small lice in their inte- 

 rior.' Possibly the excrescences may be caused by some minute 

 moth (Tortricidous or Tineidous), as there are evidences of some 

 little larva that has eaten away the parts between the cuticle at the 

 base of some of the excrescences. Your specimens I have examined, 

 but do not find any fragments of the insects, although there are 

 traces of dung and a small part of a web, certainly remains of a 

 moth ; and there is no reason why the excrescences may not be the 

 nidi for the eggs of an Eriosoma (an aphididous insect), and the 

 web, dung, and eaten part, evidences of some Tinea. Mr. Doubleday 

 has observed similar warts on leaves, but knows not how they are 

 produced." 



