1913.] 141 



difficult one to deal with satisfactorily. Attempts have been made to 

 establish specific distinctions on all sorts of characters — differences in 

 colour ; in the structure of the antennae : the form and sculpture of 

 the vertex, and the scutellum ; etc., etc. But it seems now generally 

 admitted that in every one of these points individuals vary to almost 

 any extent ; and that to be really certain of a " determination " in this 

 genus, it is generally necessary to have evidence as to the food- 

 plant to vrhich the specimen in question was attached, or, if it 

 be a ? , to examine the " saw " and its appurtenances under fairly 

 high powers of the compound microscope. Certain forms may indeed 

 be named with some confidence by the colour alone. Yet there are 

 other cases in which this criterion breaks down altogether, at any rate 

 when we are dealing -with the (j" (J . I may add that there is a good 

 deal of discrepancy in the nomenclature adopted by various authors, 

 certain old Linnean names {lutea, femorata, etc.) appearing in all 

 their lists, but being applied to different forms. It is therefore with 

 some hesitation that I offer the following tabulation of the species 

 known to me as British, which after all are only three, and should be 

 called (I believe) respectively, femorata, L., connata, Schrank, and 

 lutea, L. A British (^ , given to me by Mr. McLachlan, was referred 

 by Konow to a fourth species (fagi, Zadd.) ; but I have never felt 

 satisfied with the determination, and Dr. Enslin (to whom I have 

 lately submitted the insect) believes it to be only a var. of femorata. 

 A very distinct species, quadrimaculata, Miill. (var. hnmeralis, Geoffr.) 

 is reckoned as British by Cameron under the name hnmeralis. But it 

 rests only on a supposed capture of Leach's " near Salisbuiy," and the 

 record is in need of confirmation. Personally I suspect that, like other 

 Leachian specimens, this is an Italian (or at least a Continental) 

 intruder in our lists. If it is really British, it may at once be identi- 

 fied by its bright sulphur-yellow pronotum, and the interrupted fasciae 

 of the same colour on the upper surface of its abdomen. 



TABLE OF BKITISH CIMBEX, spp. 

 1. Wings with a broad fuscous apical margin, and a conspicuous fuscous 

 streak running from the stigma over the bases of the radial and cubital 

 areas into the 1st medial cell (= cellula furcata, Thoms.), half of which 

 it occupies. Colour variable ; may be almost entirely fuscous in both 

 sexes, or more or less largely rufescent on the abdomen i var. sylvarum, T.), 

 or with abdomen black and yellow (var. varians. Leach, and var. ^pallida, 

 Steph.), or with abdomen almostjentirely reddish-yellow (var. griffini. 

 Leach). In all cases the abdomen is considerably more shining in the 

 ? ? (and slightly so, 1 think, in the S S also) than in our other species. 

 All the forms are attached to the Birch .femorata, L, 



