The Zoologist— May, 1868. 1205 



examination of juniper-bushes during the spring would probably lead 

 to the discovery in this country of the two last-mentioned insects" 

 (Zool. S. S. 1184). I never yet met with these swellings, and should 

 feel obliged for a specimen to any observer who would kindly send 

 me one. 



Yellow Toad-flax (Linaria vulgaris). — Pea-sized, pale yellow or 

 white gall, produced by Gymnetron Lin arise of Panzer. "Are not 

 uncommon here, Allonby, Cumberland, but one has to pull up a great 

 many roots to find them. I am trying to get at the insect by planting 

 the roots in small pots." — W. A. in lilt. August 16, 1867. 



Oak (Quercus Robur).* — I possess a long series of galls, mostly 

 hymenopterous, collected both in England and abroad, on various 

 species of oak, but space forbids me to enter into the subject here. 

 I could not yet obtain possession of specimens of the so-called 

 "woolly gall," the root-gall of Cynips aptera, and the currant-gall of 

 the catkin, and 1 mention these gaps in my collection to bring them 

 to the knowledge of entomologists who may feel disposed to help me 

 in filling them up. 



Black Poplar (Populus nigra). — Leaf-stalks distorted by one or 

 more fruity-looking swellings, occasioned by the Aphis, Pemphigus 

 cursarius of Linneus, found near Basle, in September, 1862. I have 

 mentioned a fossil species of this genus in my introductory remarks. 

 The observation of these contortions on the leaf-stalk of the black 

 poplar has led me long ago to the idea that there must be some 

 analogy between the growth of pulpy fruits and that of fleshy galls, 

 and indeed if we cut any of the softer galls transversely we meet with 

 a similar grain as in many fruits : the knife discolours and spoils not 

 only the apple, but also the oak-apple ; and, as to exterior changes, 

 I have watched these poplar leaf-stalks, first in a green, hard state, 

 gradually assuming the red cheeks of ripe fruit, then the rich yellow 

 of a very ripe pear, and afterwards the sober tints of decay, brown and 

 black. I have also noticed that the tree sheds these distorted leaves 

 much earlier than sound ones. The Rev. H. J. Berkeley has years 

 ago commented on various striking resemblances between cryp- 

 togamic plants and galls. f Resemblances between fruits and galls 



* The Rev. T. A, Marshall is at present publishing, in the pages of the 'Ento- 

 mologist's Monthly Magazine,' a series of exhaustive articles on the Cynipidae of 

 Great Britain, which will be quite indispensable to future inquirers in this field. 



t In his paper, " On a Gall gathered in Cuba," &c. (Trans. Linn. Soc. 1841, t. 18, 

 p. 575. 



