i»i«.] 229 



TRIOZA PROXIMA Flor AS A BRITISH INSECT. 

 BY RICHARD S. BAGNALL, F.L.S. 



A generation ago, in the days of Douglas and Scott, some attention 

 was given to the Psyllidae, and useful work was encouraged and 

 achieved by those conversant with Continental literature which help- 

 fully suggested particular search for certain species not then recorded 

 as British. Thei-e is much room for guidance of that nature, as many 

 insects will only be discovered by special search — in brief, though a 

 good deal may be done by general collecting, very much more may be 

 achieved by a knowledge of the European species, theii' food-plants 

 and habits, and their distribution. 



Although Psyllids as a family cannot be classed as gall-causers, 

 many — especially of the genus Trioza — leave signs which, to those who 

 can read them, indicate their presence. Trioza proxima Flor is a 

 case in point, and its presence on the mouse-ear hawkweed (Hieracinm 

 pilosella) is advertised by deformed leaves ornamented to a greater or 

 less degree by wart -like tubercles or " embossments " open on the one 

 surface. This is illustrated in Houard's Les Zoocecidies des Plantes 

 d'Etirope, Vol. II, p. 1054, figs. 1363-1365. 



Of all species of Rieracium, H. lyilosella is by far the most 

 interesting to Cecidologists. In his " British Plant Galls " Mr. Swanton 

 records Macrolabis pilosellae Binnie, Tephritis ruralis H. Loew, and 

 Tylenchus [^I'eracu' Connold] from that plant. Mr. J. W. H. Harrison 

 and I have given some attention to the plant during the past two years, 

 noting eleven different galls, including those caused by a Cynipid, 

 Aulacidea pilosellae Kieff., and three Cecidomyiids, Stictodiplosis 

 pUosellae Kieff., Perrisia nervicola Kieff. (= Houard No. 6205), and 

 Cystiphora pilosellae Kieff., new to the British faima. 



But, though we have examined plants from so many parts of the 

 north of England, we have not yet actually taken Trioza prozima, 

 though I have succeeded in discovering its galls on two occasions, last 

 month on Penshaw Hill, and to-day at Roker, near Sunderland, a 

 larval form of Psyllid occurring in the first instance. 



Macrolabis pilosellae, Aulacidea pilosellae, and Perrisia nervicola 

 also occurred at Eoker, on the same patch of plants. 



Penshaw Lodge, Penshaw : 

 September loth, 1916. 



