368 ARACHNOIDEA. 



CASE do not change colour, are quite loosely rolled in the spring, later 

 on harden, and become firm and brittle. Inside there is an 

 abnormal hairy lining ; the gall mites living there are of a yellow- 

 ish colour. 



Phytoptus Sp. 



Pouch-like deformities on a small part of the edge of the leaf 

 of Salix alba, L. The edge of the leaf is for a short extent much 

 drawn out, then much turned up, through which a closed, some- 

 what swollen pouch appears, which almost always stands on the 

 edge of the leaf, often projecting far over it, rather cartilaginously 

 thickened^ wTinkled on the upper side, and usually of a light green 

 colour. This pouch, many of which appear on one leaf, have a 

 very scanty lining of hair, and contain reddish gall mites in small 

 numbers. 



Phytoptus Sp. 



Dr. Thomas described (1. c. -^2)^ Bd. 1869, p. 332, No. 5) similar 

 galls on the leaves of Salix fragilis, L. in the herbarium of Professor 

 A. Braun, which were otherwise furnished inside from those de- 

 scribed above, therefore not entirely agreeing with them ; they had 

 been before met with and were described (1. c. 39 Bd. 1872, 465,) 

 by him in the Swiss Alps on Salix herbacea, L., from | to i| 

 millimetres in size. 



On the Poplar. 

 Heliaczeus populi, Kirch. 

 This is one of the mites observed by Dr. Leop. Kirchner : it 

 appears at the petiole, close under the base of the leaf; orange- 

 coloured, of the size of a lentil, with small red wart-shaped galls 

 on Populus tremula. 



Batoneus populi, Kirch. 

 These mites are said to be gregarious, living in manj-chambered 



