Galls caused by the larvoe of Xestophanes potentillae 

 Cam. 



on 



the stems of Potentilla reptans Linn. 



PLATE 44. 

 Synonymy of Insect. 



Cynips potentillcB De Vill. 



Aulax splendens Htg. 



„ poteiitilhc Schenck, Marshal!, Mayr. 

 „ abbreviatus Thorns. 

 Habitat of the Cinquefoil.— Along hedgerow banks, edges 



of woods, borders of meadows, by the side of most country 



lanes ; abundant in Britain, except parts of Scotland. 

 The Gall is formed by a gradual and persistent accumulation 



of sap around the ova deposited beneath the cuticle of the 



stem. 

 Position. — On the stems, and occasionally on the leaf-stalks. 

 Manner of Growth. — Conglomerated ; .sessile ; glabrous. 

 Colour. — At first green, later pink, changing to purple ; when 



mature, nut-brown. 

 Average Dimensions of a Mature Specimen. 



Length, 8 mm. ; girth, 12 mm. 

 May be sought during the months of July to November. 

 The Growth is complete by the end of October. 

 The Typical Condition of the gall is plurilocular. Usual 



number of cells, 6. 

 The Larv/E pupate in the gall. The imagines emerge during 



the spring. 

 Parasites. — Torymus globiceps Nees., T. ater Nees., Oligosthenus 



tibialis Nees., Eucyrtus zcphyrinus Dalman, Pezomacluis 



potentilla Gir. 



Like X. brcvitarisis, this species attacks the same plants 

 year after year, leaving other clusters of Potentilla reptans 

 untouched. 



The gall is also figured by Peter Cameron, " British Phy- 

 tophagous Hymcnoptera" (Ray Society), vol. \\\, plate 11. 

 117 



