The Zoologist— May, 1868. 1203 



me from Basle, where Mr. Stehelin-Im Hof collected it in June, 1867, 

 on an elm with smooth twigs. Mr. Arraistead found it near Nancy and 

 Mannheim in the same month, and it occurred to me near Penge, in 

 July of the same year, rather abundantly on an elm-bush, the bark of 

 which is dilated in lamina, disposed lengthwise along the twigs. Can 

 any botanist give me the scientific name of this variety of elm.* A dis- 

 cussion on this gall took place before the Entomological Society of 

 London on the 5th of November, 1866, and to Mr. M'Lachlan we are 

 indebted for a handy resume of the observations of previous authors 

 who wrote on these and allied galls (' Entomologist's Monthly Maga- 

 zine,' vol. iii. pp. J 57 — 159), to which Mr. H. C. Cooke has added 

 some interesting facts at p. 190 of the same periodical. My friend 

 Mr. H. Knecht, of Basle, sent to me, in September, 1866, specimens 

 of broad elm-leaves collected near Basle, on the upper side of which 

 there stand numerous pedunculated, fig-like, hollow excrescences, of 

 the size of a small bean, green, tinted with purple-red. These galls 

 were filled with winged individuals of an Aphis, which I refer with 

 doubt to Tetraneura Ulmi of Kaltenbach. A translation of Kalten- 

 bach's extracts from Von Gleichen's work, referring to the preceding 

 or an allied species, has been given by Mr. M'Lachlan in the paper 

 quoted above. I am inclined to say that though Kaltenbach, as 

 quoted by Mr. M'Lachlan, could find no differences between the 

 tenants of his large and small galls, that the two species of Aphidae to 

 which I refer the two kinds of galls mentioned by me above are as 

 distinct from each other as two insects belonging to the same family 

 can possibly be : the entomological proof for this assertion remains to 

 be given, but iu the mean time I would simply ask the question, has 

 any one ever bred the same insect from galls of a different shape and 

 of a different location— say, for instance, from a large purse-shaped 

 gall formed by the transformed leaf and fig-like small pedunculated 

 galls, standing in numbers and independent of each other on one and 

 the same leaf? I think not,t and it is not going too far to assert that 

 the size and shape, texture and covering of most galls, their location 

 on the bud, leaf, twig, trunk or root, are regulated within certain 

 limits by laws as inviolable as those governing other organisms; 

 that we meet here and there with exceptions need not disturb 



* Is it Ulmus suberosus? 



t I am quite aware of the Rev. T. A. Marshall's valuable observation on the two 

 galls of Spathegaster baccarum, Linn. (Eut. Monthly Mag. vol. iv. p. 225), but the 

 form and structure of these is identical, and only their location differs. 



