r8 93 J 



THE BRITISH NATURALIST. 



5 



Var. pulchella, Jenyns. — Musco Sic dyke, Beeston, and Stanton-on 

 the-Wold, Lowe. Common in the lake at Thorsby, Musson. 



Var. cinerea, Alder. — Beeston and Lenton, Lowe. The lake at 

 Thorsby, Musson. Clumber lake, Jeffrey, where Mr. Musson also 

 found it plentiful. . 



Var. pallida, Gassies. — Mentioned by Dodd and Musson in their 

 catalogue without docility. 



Pisidium pusillum, Gemiin. — Common in rivers, canals, and ponds 

 and in the ditches in the Nottingham meadows. 



Var. obtusalis, Lam. — Beeston, Lowe. Beeston and Attenboro\ 

 Musson. 



THE PTEROPHORIN A OF BRITAIN. 



BY J. W. TUTT, F.E.S. 

 (Continued from Vol. II., p. 254). 



Referring to the best time to search for larvae, Mr Smith 

 writes : — " When fleabane (Inula dysenteric! ) is making its appearance, 

 the unfolding and proper development of some of the shoots, 

 especially terminal ones, appear impeded ;" examination will in all 

 probability show the check to be due to the presence of young 

 CE. lithodactylus larvae. This is the best time to secure them, as they 

 are almost certain to be free from parasites. Later the larvae may 

 be found on the upper sides of the expanded leaves, if looked for just 

 after dark. Patches of the fleshy part of the leaf are eaten away> 

 exposing the skeleton and rendering the plants infested very 

 conspicuous objects. This species is said to feed also upon Conyza 

 squarrosa in a like manner ( ;< Entomologist," Vol. XV., p. 104). Mr. 

 Gregson writes of the habits of this species: — " This is another 

 species which is useful to man, living as it does, on a noxious w T eed 

 which so abounds in some limestone sheep fells in North Lancashire 

 and Westmoreland, that anything that has a tendency to check or 

 destroy it must be esteemed useful ; for although the husbandman 

 may work ever so hard in extirpating the low growing plants, he is 

 powerless on the rock faces and narrow ledges from whence the seeds 

 are regularly scattered ; but here we have one of Nature's agents, 

 an insect which so consumes the leaves that the plant 

 dies, and useful herbage springs up, where once a wide-spreading and 

 useless plant encumbered the ground. I may remark incidentally, 

 that I have selected instances of useful insects from those whose life 

 history is either unknown or imperfectly known. I do not know a 

 single species of the genus Pteropkorus that feeds upon a useful plant, 

 although, in England, Pterophorus rhododactylus feeds on, but does not 



