( XXV ) 



" F. crassiorella has a comparatively short spur to the 

 anterior tibia (length y^Q-ths of the tibia), over twenty joints to 

 the antenna, and rarely has the median accessory cell. The 

 female has a diminished number of tarsal joints. These charac- 

 ters always suffice to separate it from all other British forms. 



" F. casta. This n<ame, having priority over the well-known 

 name of nitidella, may be taken to cover the remaining British 

 forms of Fumea. In endeavouring to determine whether any 

 of these forms deserve separate specific rank, I have come to 

 the conclusion after examining a great deal of matei-ial, that 

 the size or material of the case, the size or colour of the 

 imago, and the form of the wing afford no definite data for 

 specific distinction. Size is perhaps the most reliable of all 

 these ; but it is unnecessary to point out how i-arely this 

 character is of much value. 



"The females present no definite characters, at least so far 

 as I have been able to examine them from the material at my 

 disposal. All have five joints to all the tarsi, and the only 

 differences are slight ones in the form of the tarsal joints, 

 probably due to drying, and a difference in the bristles with 

 which the legs are clothed, due perhaps to the state of pre- 

 servation of the specimens. 



"The question as to whether we have more than one species 

 under the name of casta must remain more or less doubtful, 

 until the several forms have been bred largely from the egg, 

 which seems to be an easy process under proper arrangements. 

 In the meantime the following forms are distinguisliable, 

 some of them obviously being local races with many of the 

 features of distinct species. 



" The nitidella form is probably the commonest and most 

 widely distributed; it expands 12 — 13 mm,, and is, when 

 fresh, very dark in colour; it has eighteen joints to the antenna, 

 and a tibial spur of a length equal to y^oths of the tibia. This 

 is probably Bruand's rohoricolella, the anal tuft of the female 

 being often pale, but never white. (Bruand notes that in his 

 anicaiiella it is snow-white, and in rohoricolella, white.) There 

 is a larger form which I take to be inter laedlella. It differs 

 in having 18 to 20 joints to the antenna?, a tibial spur of y^^hs 

 the length of the tibia, and a wing-expanse of 13 — -14 mm. 



PROC. ENT. SOC. LOND. V., 1900. D 



