114 [May, 



Thomson in his " Ofversigt af Scandinavicns Chermes-arter" (Op. Ent. viii, 

 1877) includes Chennes sorhi L., but his description leaves it uncertain whether 

 he was really referring to the Mountain Ash species or not. Although Eeuter 

 had already recorded from Mountain Ash a Psylla which he thought was 

 P. mail, F. Low (Verh. zool.-bot. Ges. Wien, xxxii, 1882, p. 250) says that no 

 Psylla living on Sorhiis Aucuparia had yet been found, and therefore it was 

 very probable that the presence of Linne's Chermes sorhi on Mountain Ash 

 was accidental. In the neighbourhood of Northwich, where Mountain Ash 

 is a dominant tree, I found on the latter a pale Fsylla commonly in August 

 1910 and with considerable doubt put away the specimens as P. mali. The 

 next season I looked for a Psylla on Mountain Ash here and found it at once, 

 both on trees undoubtedly native, of which there are very few, and on planted 

 ones which had been brought in the young state from Scotland. It was now 

 perfectly clear that notwithstanding the similarity of the green nymphs and of 

 the male forceps, the Mountain Ash insect could easily be distinguished from 

 P. mali which was living on Crab Apple a few yards away. The following 

 particulars will serve for its recognition : — Upper fore-parts whitish-yellow 

 inclining to orange and not to green ; mesonotum with a pair of wide stripes 

 on each side and a line down the middle lighter or darker yellow-brown. 

 Dorsiilum entirely brown. Anteniiae about half as long as the costa, the 

 fourth and following joints ringed with black at the apex, last joint entirely 

 black. Elytra hyaline, the veins becoming darker from the basal third 

 onward, cell M well covered with tubercles throughout except on a well- 

 defined marginal area, the latter very evident in the basal third of the cell, 

 cell a 2 pale throughout. Length 3*o-4 mm. P. mali, which is a more 

 robust insect, does not develop the dark line down the middle of the meso- 

 notum and has cell M practically free from tubercles from its base as far as 

 the fork of Cu. I have also seen P. sorbi from Hyde Heath, Bucks [JE. A. 

 Butler), and Great Salkeld, Cumberland {Britten). — J. Edwaeds, Colesborne : 

 April dth, 1918. 



I^^ote on Trioza velutina Forster. — Dr. Karel Sulc, whose writings on 

 Psyllina are unequalled for completeness of morphological investigation, 

 accuracy of description, and wealth of illustration, deals very fully (Mon. Gen. 

 Trioza, Pt. iv, p. 88, t. 47, 48) with T. galii and T. veUdina Forster ; and as 

 the result of his examination of the type-specimens, amongst others, he comes 

 to the conclusion that they are one and the same species. But the facts 

 which he demonstrates also prove most conclusively that we have to deal 

 with two kinds which differ from one another in_certain definite and well- 

 marked particulars ; namely, the tuberculation of the elytra and the form of 

 the forceps ; and since the researches of the learned doctor go to show that 

 these are constant whilst the shape of the elytra and the shape and bulk of the 

 face-cones, features on which he relies in support of his amalgamation of the 

 two forms, are decidedly variable, it would appear better to retain the names 

 as applied by Forster and call the form with no tubercles on the elytra except 

 a few in the neighbourhood of the base of a 1, and the extreme tip of the 

 forceps in the dorsal aspect shaiply truncate, yalii, and the form with the 

 elytra well covered with tubercles except at the edges of the cells, and the 

 extreme tip of the forceps in the dorsal aspect bluntly rounded, velutina. The 



