296 PROCEEDINGS OF THE 



not always affect the same species of willow ; and it is obvious 

 that a gall on a hairy-leaved willow, like Salix aurita, must be 

 different from one on a plant like Salix imrimrea ; in the former 

 case it will be white and hairy; in the latter, smooth, bright 

 green, and mottled with red. Such being the case, it is apparent 

 that before the species can be satisfactorily elucidated, we must 

 have full information regarding the galls and larvae, as well as the 

 perfect insects, from all parts of the country. 



I am now able to add a well-marked gall-making Saw-fly to 

 the British list. I found the galls while at Rannoch, in June, 

 1872 ; and in the following spring succeeded in rearing a" good 

 series of the imagines. I could not identify it with any of the 

 described species ; but, to make certain, I forwarded some speci- 

 mens to Dr van Yollenhoven, who, with his usual kindness, 

 informed me that the insect was perhaps Nematus proximus, Lep. 

 (Mon. Tenth., G7, 201); but as the description was rather 

 ambiguous, he could not be certain regarding it. Stephens 

 having described N. irroximus (Brit. Ent., vii., 36, 40), I 

 then sent the Rannoch species to Mr Fred. Smith, to be 

 compared with the Stephensian types in the British Museum. 

 This Mr Smith did, with the result that Stephens' insect 

 proved to be quite another species. The description of N, 

 proximus being so vague, I thought it better to consider the 

 present species as undescribed, and accordingly attached a name 

 to it. Last month, however, I Avrote to Professor Zaddach of 

 Konigsberg, concerning it ; and he tells me that it has 

 been long known to him, and in his collection is placed under 

 the name of Nematus femoralis, but is not as yet described. In 

 these circumstances I have adopted the name of tlie German 

 Professor ; and have drawn up the following description of the 

 Saw-fly and its habits, so as to enable the British student to 

 recognise it. 



The larvae live solitary in galls, on a species of Salix. What 

 is the species of willow upon which I found them, is a little uncer- 

 tain ; but my friend Mr Richard M'Kay thinks that it is probably 

 Salix lamina. Near Danzig Herr Brischke finds them on S. 

 purpurea (teste Zaddach, in lit.) The galls are usually in pairs on 

 the leaf, placed opposite to and nearly always touching each 

 other. They project to some extent above the upper, but not at 

 all from the lower side of the leaf In form they are usually 



