AN EASY METHOD OF IDENTIFYING CNEPHASIA. 99 



An easy method of identifying the species of the genus Cnephasia 

 = Sciaphila (Tortrlcidae). (With /ihtte.) 



By F. N. PIERCE, F.E.S., and the Kkv. J. W. METCALFE, F.E.S. 



The Sciaphilas, as they are generally termed, have long presented 

 such insurmountable difficulties to collectors that they have practically 

 given up the genus in despair, and have placed such speciiuens as they 

 have received from correspondents in their cabinets under the name 

 sent rather than attempt to settle their identity for tbemselves. That 

 this state of affairs is general is evident from the mixed series forwarded 

 for examination from many collections. Here the study of the genitalia 

 steps in, and separating the specimens with indisputable accuracy 

 removes the problem from the sphere of individual opinion. 



Entomologists, when in future setting their captures, would do 

 w«ll to open the valvse as far as possible whilst the insects are still on 

 the boards, and thus make subsequent examination a simple matter. 



In order first of all to discover how many British species the group 

 contained it was necessary to make microscopical mounts of many 

 named specimens and unnamed varieties. This having been done it 

 was not a very difficult matter to determine to which species each form 

 belonged. Having thus obtained reliable examples of all the British 

 species, the question as to whether a simpler and less destructive 

 method could not be devised for determining the species by means of 

 the genitalia, since collectors not unnaturally object to the breaking up 

 of each specimen, in order to discover to what species it belongs. 

 With this end in view a thorough examination was made of dried but 

 unmounied examples of all the species, using the already mounted 

 examples as a guide. The method of working is as follows: — 



Hun a knife across a piece of flat cork, and then pencil the slit so 

 that it may be readily found. Next, by pushing the head of the pin 

 (holding the point by the forceps) into- the slit, the insect is held 

 securely with the ventral surface of the abdomen in position for exami- 

 nation under the microscope. Having brought the genitalia into focus 

 and arranged a bull's eye condenser so as to illuminate brilliantly the 

 part, remove by means of a small sable brush (Vv'^. and N., No. 00) 

 sufficient scales to expose the junction of the valvte. At first it will 

 probably be found necessary to lay bare both valvw, but when the eye 

 gets accustomed to the appearance the merest touch is sufficient to 

 determine the species. With the aid of the drawings, herewith given, 

 of the genitalia as thus seen with the scales removed, no one should 

 have the siuallest difficulty in naming his male captures. Once having 

 located the mnles, but little further trouble should be experienced in 

 mating the females. 



The dili'erent species are subject to great variation in wing mark- 

 ings, but I'irhaps the most difficult to determine superficially are those 

 which tend towards albinism, the markings almost entirely disappear- 

 ing, and we are left with a chalky white specimen and nothing to guide 

 us as to lis species except the shape of the wing, which is so variable 

 as to be absolutely useless. The examination of the genitalia, how- 

 ever, at once determines the question. 



Before describing the distinguishing features of the genitalia in 

 each case, attention must be drawn to certain difficulties in the 

 nomenclature. 



