GALL MLTES. 345 



:ase (Phytoplus vitis), four stumps on the under side of the body, 

 which he supposed were the aborted remains of the two missing 

 feet. The extent and meaning of his statement rather than the 

 accuracy of this observation has been questioned. 



Since that time the Phytopti have become tolerably well 

 known: that is, many observers have made themselves acquainted 

 with them; and a few have, from time to time, described various 

 species and the galls in which they have been found. The more 

 important contributions of this nature have been furnished by 

 Frauenfeld, who, in the years 1864, 1865, 1869, 1870, and 1872, 

 has published papers on the subject in the " Verhandlungen 

 Zoologische und Botanische Gesellschaft in Wien ; " by Dr. 

 Thomas in the " Zeitschr. Gesam. Naturw. (xxxiii)," and on 

 Swiss Phytopti in the "Verh. St. Gall. Ges., 1870— 1871," and 

 by Dr. Franz Low in " Verhand. Zool. and Bot. Ges. Wien " in 

 1874. In our country they seem to have been very little noticed. 

 Apparently the first original observation was by the Rev. M. J. 

 Berkeley, the eminent vegetable physiologist, to whom specimens 

 of currant-buds, injured by a species of Phytoptus, had been sent, 

 in 1869. These he brought before the scientific committee of 

 the Horticultural Society; and, from these and other specimens 

 Professor Westwood shortly afterwards described the species in 

 the " Gardener's Chronicle." His description agrees with that of 

 other authors, and need not detain us, but he has added, appa- 

 rently on the authority of his correspondents, that at a later 

 period of its life it acquires six legs. This is an important point, 

 and deserving of further examination, for it has not been observed 

 by any other author. He says, " From this statement it is evident 

 that this creature retains its juvenile two-legged form for a con- 

 siderable period, but at a later period (as we learn from T. C. of 

 Glasgow, a good microscopic observer) they acquire six legs, as 

 was seen in specimens from old buds sent to us near the end of 

 October, when some had two well-developed bristles at the tail. 

 These two bristles we believe to be the rudimental fourth pair of 



