84 C A i jri1 ' 



better optical apparatus now at my command I saw at once that I 

 had been the victim of what microscopists call an '"error of interpre- 

 tation," and that the appendages were absolutely the same in both 

 hippocastani and lethi"rryi ; I had been misled by the circumstance 

 that in my type slide of the latter the long arm of the right appendix 

 posterior had become superimposed upon the left, whilst the outline 

 of the short arm on both right and left appendices had remained 

 distinct, hence the appearance of three app. post., two short and one 

 long. An error of this kind would have been impossible if I had 

 examined the parts in question in situ, but in 1SS0 it had not occurred 

 to me that such a course would be practicable, nor had I then realized 

 that the natural orientation of the parts is more characteristic than 

 their outline as one sees it after they have been squeezed flat in 

 Canada balsam between two pieces of glass. The following is an 

 amended description of the appendages of the oedeagus in T. lethierryi 

 (and T. hippocastani) : — App. sup. ascending divergent subterete, 

 furcate before their half-length, the branches acuminate, the outer 

 one about thrice as long as the inner ; app. inf. subequal in length to 

 the app. sup., furcate from a very short base, the branches falcate 

 approaching at the tip, the upper one ;ibout one-third shorter than 

 the lower. So far as I know, the unequally-forked app. sup. is 

 absolutely diagnostic of this species. 



TyPIILOCYBA FRUSTRATOR, H. sp. 



An entirely pale species of the ronx group. & : crown, pronotum, and scutellum 

 ivory-white ; corium canary-yellow ^chrome-yellow), more or less inclining to 

 orange, membrane not obviously fumose. CEdeagus : app. .sup. simple, sword- 

 shaped, acuminate, directed outward, forward, and, in their ultimate third, upward ; 

 app. inf. a little longer than the app. suj)., furcate from a base which is about one- 

 half as long as the branches, the latter falcate, moderately curved, approaching at 

 the tip, subequal in length. $ : crown and pronotum ivory-white, scutellum 

 reddish-white, corium canary-yellow (chrome-yellow), membrane not obviously 

 fumose. 



This species forms a moderate proportion of the clouds of 

 yellow Typhlocyboe which one beats from various broad-leaved trees, 

 especially elms and beeches, towards the end of the year. 1 have 

 found it here and in Norfolk. 



Typhlocyba fratercula, n. sp. 



Another entirely pale species of the rosse group. $ : crown, pronotum and 

 scutellum ivory-white, corium canary-yellow (chrome-yellow), more or less inclining 

 to orange, membrane not obviously fumose. CEdeagus: app. sup. simple, divergent, 



