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THE PSYLLIDZ OF THE CLEVELANDS: 
J. W. H. HARRISON, B.Sc. 
Tue following list of the Psyllids of a limited section of the 
Cleveland area is neither exhaustive nor final, for it compares 
badly with that for Durham, in which county an equally 
limited area has been worked. It is hoped, however, that 
many of the missing species will turn up when districts further 
afield’ are worked ; there is little prospect of their discovery 
in the Middlesbrough neighbourhood, as they are chiefly feeders 
on low plants of which there is but little variety here and, what 
is more important, those that are present refuse, after per- 
sistent working, to yield anything further than the ubiquitous 
Trioza urtica. 
Livia juncorum Latr. A rush feeder distorting rushes 
in most localities, but curiously local everywhere, sometimes 
occurring on a single patch of rushes in one field, and apparently 
absent from what seems an equally suitable bed in the next ; 
also locally plentiful on the moors. 
L. crefeldensis Mink. Rare on sedges around an old estab- 
lished pond near Stainton. 
Rhinocola ericae Curt. A tiny species not 2 m.m. in length, 
formerly supposed to be rare but recently proved to be abun- 
dant throughout Durham, Northumberland and North York- 
shire, on heather, Calluna vulgaris; is especially numerous 
on Great Ayton Moor where it is dimorphic. 
Aphalara calthae Lin. Fairly common on larch and spruce 
in November, although its food is knotgrass. | Marton, etc. 
Psyllopsis fraxinicola Forst. Everywhere common on ash. 
P. fraxint Linn. Almost as common as the last and equally 
widespread—also on ash. . 
Psylla pyricola Forst. A single specimen beaten from 
mountain ash, Lonsdale. 
P. salicicola Férst. Not common, on sallow, Hemlington, 
Nunthorpe. 
P. ambigua Forst. Very common on sallow in May and 
June, Nunthorpe, Marton, etc. 
P. hartigii Flor. A few beaten from birch in June, Great 
Ayton. 
P. pineti Flor. Common, beaten from conifers at Eston, 
Gunnergate and in Lonsdale. 
P. melanoneura Foérst. Common late in the year—not on 
its reputed food-plant hawthorn—but on oak, conifers, etc. 
Generally distributed. 
P. costalis Flor. Common, obtained from blackthorn, 
hawthorn, mountain ash, oak, etc., throughout the district. 
P. peregrina Foérst. In multitudes from every hawthorn. 
Naturalist 
