1S90.] 287 



XOTES CONCEENING PSOCUS QUADRIMACULATUS, LATREILLE, 

 OF WHICH PS. SUBNEBULOSUS, STEPH., IS A SYNONYM. 



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



In August, 1863, Mr. P. C. Wormald and I took a few examples 

 of Ps. quadrimaculatus on an old lichen-covered paling at West End, 

 Hampstead, near London, a locality now probably useless for entomo- 

 logical purposes. All the specimens I retained were $ . Up to 

 within the last few days, I had never again seen the insect alive in this 

 country, nor do I know of recent captures of it by others. On the 

 continent, with one or two exceptions, it is recorded as rare in recent 

 local lists. 



Near the end of the present month (September, 1890) I was 

 staying at the charming little town of Dunster, in North Somerset. 

 The hotel in which I lodged is a recent structure, only four years old, 

 built of ironstone. On the outside wall I found Fs. quadrimaculatus 

 in great abundance, chiefly on the lines of cement between the blocks 

 of stone. In less than an hour I captured over 100, at the eye-line, 

 in the space of two yards, and it would have been quite easy to have 

 taken 1000 ; each successive day showed them in the same abundance. 

 Why they were there remains a mystery ; possibly they were the de- 

 scendants of others brought with the stone from the quarry. The 

 wall being nearly new had no covering of lichens, algae, or debris of any 

 kind, save a few recent spider webs. An examination of adjacent 

 walls, old and lichen-covered, failed to produce the insect. 



This long series enables me to give some useful notes on the 

 species. I arrive at the conclusion that most (or all) of the published 

 descriptions of it have been drawn up from the $ , which sex is little 

 variable in the pronounced markings of the anterior-wings. But the 

 (J is considerably variable. In the ? the oblique marking intersected 

 by the fourth branch of the lower forked-vein (and opposite to the 

 pterostigma) is as dark as the dark spot in the pterostigma. In the 

 $ it is frequently absent altogether, and when present is very pale 

 grey, like the more basal cloudings, and, in more extreme cases, these 

 cloudings are also absent, the only markings being the dark pterostig- 

 matical spot, and the dark points at the commencement of the 

 pterostigma, and the end of the anal vein. 



In my Monograph of the British Psocidce, Ent. Mo. Mag., vol. iii 

 (1867), I stated that it appeared doubtful if Coquebert's fig. 7, given 

 as representing a variety of quadrimaculatus, had anything to do with 

 that species. I now see in it a tolerably good representation of the 

 (J in well-marked specimens. 



