Xestophanes potentillae. 



The plant Potoitillce reptans may be easily distinguished 

 from its congener, P. toniientil/a, by the facts that its leaves are 

 pedunculated instead of sessile, much larger in size, and ordi- 

 narily composed of five leaflets coarsely serrated in outline ; 

 the petals, although the same colour as those of P. tormentilla, 

 are larger and ordinarily five in number, but the stems are not 

 so erect. When Xestophanes potetitilla; lays its eggs during the 

 month of June, the punctures give rise to peculiar, oval-shaped, 

 and irregular-sized swellings, sometimes projecting more on 

 one side of the stem than another, but generally the swelling is 

 evenly distributed, with a tendency to assume a spindle shape. 

 The gall-growths occur along the stems singly, or in twos and 

 threes at irregular intervals from the root to the last leaf, and 

 also on the petioles. During the first few weeks of growth the 

 swellings are soft and succulent, greenish or pinkish in colour ; 

 later, however, the texture becomes more woody, and ultimately 

 hard. The colour changes to a nut-brown, and growth is 

 complete. The dimensions of the galls are very variable. A 

 single cell will seldom be found exceeding i6 mm. in girth, 

 whereas swellings containing six or seven cells will attain 30 mm. 

 in girth and 15 mm. through its long axis. Anastomosis is 

 neither so frequent nor so pronounced as in X. tormentilla, but 

 examples are occasionally found where many grow upon the 

 stems, and resemble small peas threaded on stout string. 



The illustration is of specimens gathered at Battle by the 

 author. 



