1900.] 149 



Bridgmau mentions a specimen of AjJt. vcstigialis in which the 6th 

 and 7th joints of the antennae were only partly, instead of entirely, 

 reddish-brown, and 6-11 white above only instead of ringed. I 

 incline to consider the presence or absence of a rudimentary scutellum 

 one of the first points for a division of species in this genus {Pezo- 

 machus, as limited by Foerster), next to which I would place the 

 sculpture of the abdomen, and then the length of the antennae, the 

 relative length of the individual joints, and the colour. I believe that 

 these, with the shape of the 1st abdominal segment, will enable us to 

 obtain a more satisfactory and natural grouping of this difficult genus, 

 and when worked out, it will doubtless facilitate identification of 

 specimens. 



It seems possible that the genus Pezomachus may eventually dis- 

 appear, being entirely absorbed into other genera having winged 

 males ; and even the known apterous males may yet prove to be only 

 varieties of winged species. 



41, Holland Park, W. : 



May, 1900. 



PLECTROCNEMIA BREVIS, McLach., AN ADDITION TO THE 

 BRITISH TRICHOPTERA. 



BY ROBERT McLACHLAN, F.R.S., &c. 



The Rev. A. E. Eaton has just placed in my hands three males of 

 a Plectrocnemia taken by him at Seaton, South Devon, in May, 1898, 

 which are to be referred to P. Irevis, new to Britain. 



This species was originally deccribed by me nearly thirty years 

 ago in this Magazine, vol. viii, p. 145 (1871), from examples taken by 

 Mr. Stainton at Sedrun in Switzerland ; and a further and more de- 

 tailed description (with figures) appears in my " Monographic Revision 

 and Synopsis," p. 396, pi. xli. Of the two already known British 

 species of the genus it could only be mistaken for P. eonspersa, Curt., 

 but, as already pointed out, it is smaller on an average, the anterior 

 wings more evenly irrorated, and practically without the longitudinally- 

 oblique darker markings usual in conspersa ; the inferior appendages 

 very much shorter, and verij obtuse, the penis very strong and curved 

 downward between the inferior appendages, &c. It is an interesting 

 addition to our fauna. Up to now I had only seen it wdth certainty 

 from Switzerland. In addition to the original locality (Sedrun), Dr. 

 Kis records it from more than one other Swiss locality : I have speci- 

 mens from him from near Ziirich. 



