XESTOPHANES POTENTILLA. 53 



Black, shining, impunctate ; the abdomen and legs reddish -yellow, 

 the latter paler in tint than the abdomen, the former more or less 

 infuscated above towards the apex ; wings hyaline ; the nervures fus- 

 cous ; antennae brownish, fuscous at the apex ; parapsidal furrows 

 obsolete in front ; the third joint of the antennas not perceptibly longer 

 than the fourth ; the fourth joints of the hinder tarsi twice longer than 

 broad. In the ? the second abdominal segment is shorter, in the $ 

 longer, than the third. 



Length 1*5 to 25 mm. 



The galls are found on the stems and leaf-stalks of 

 Potentilla r&ptans. They form irregular swellings, 

 usually of numerous cells, which may or may not 

 project as roundish protuberances from the general 

 mass. In texture they are hard and woody; in colour 

 they may be greenish, reddish, or purplish at first, 

 becoming brownish with age. They may form spindle- 

 shaped swellings of from 10 to 15 mm. in length, but 

 also they may be spherical or oval ; and, as in brevi- 

 tarsis, small isolated single cells may be found. They 

 may occur singly or in groups from the roots upwards, 

 and a series of small galls may be united to form a 

 necklace-like body. 



Diastrophus Mayri, Reinh., forms somewhat similar 

 swellings on the stem of Potentilla argentea. 



Gynips brevicornis, Curtis (B. E., 688, 19), clearly 

 represents either potentillm or brevitarsis, but which I 

 cannot make out to my satisfaction. His description 

 is " Black, shining ; abdomen bright ferruginous ; 

 legs bright ochreous ; tips of tarsi fuscous ; mandibles 

 and antenna ferruginous, the latter brownish towards 

 the apex ; not much longer than the head and thorax ; 

 13-jointed ; terminal joint longest. 1 J lines. 



"Dover." 



As parasites there have been recorded Torymus 

 globiceps, Nees, T. ater, Nees, Oligosihenus tibialis, 

 Eulophus nitidulus, Eurytoma a,brotans, Nees, Encyrtus 

 zephyrinus, Dalman, Siphonura brevicauda, Nees, 

 Pezomachus potentillse, Grir. Thomson (Opus. Ent., 

 804) records Eurytoma rufipes from his Aulax fovei- 

 frons. 



