502 



climate so modified." The excursion commenced about the begin- 

 ning of May and lasted till the end of July ; during which time Dr. 

 A. was enabled to make a large and valuable collection of plants, in- 

 cluding several species new to Styria. Specimens of the more inte- 

 resting species were exhibited to the meeting, the Society's herbarium 

 having been enriched by a very complete set through the kindness of 

 Dr. Alexander, and were greatly admired for their beauty and the ex- 

 cellent manner in which they have been preserved. 



A letter from Dr. Bid well, Albrighton, was read, announcing the 

 discovery of Vaccinium macrocarpum near Mold, in Flintshire, in Au- 

 gust last, as stated in the ' Phytologist' for March (Phytol. ii. 441) ; 

 and 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 in- 

 sects ; one of these consisted of peculiar stipitate excrescences on the 

 leaves of a North American tree, concerning which Dr. B. 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 plant-louse ; one kind is very hurtful to the peach 

 tree, but attacks the leaves in a different way to the insect on your 

 specimen. Dr. Harris, in his admirable work on the Insects of Mas- 

 sachussets injurious to vegetation, speaks of some Aphides, 'the punc- 

 tures of which affect plants in a most singular manner, producing 

 warts or swellings, which are sometimes solid and sometimes hollow, 

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

 gle individual, whose punctures were the original cause of the tumour. 

 1 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 interior.' 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. Yom* 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 rea- 

 son why the excrescences may not be the nidi for the eggs of an 

 Eriosoma (an aphidious 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." — W. W. E. 



