NEPTICULA BETULICOLA. 271 



lustre ; the cilia are decidedly of a darker grey ; moreover, in 

 N. jAaaiculella the middle tibiae are not paler than the other legs. 

 N. micr other iella may be distinguished by the narrower anterior wings, 

 suffused with violet, and before the tip almost of a pure blue, by the 

 narrow, rather oblique fascia, and by the darker grey cilia. N. luteella 

 has the disc of the anterior wings less smooth and dull, the fascia 

 is not placed so posteriorly, and perceptibly expands on the inner 

 margin, inclining to yellowish with very slight glossiness (Heinemann). 



Mine. — The mine is small, narrow and coarse at the commence- 

 ment, generally much contorted and several are often crowded together 

 in a leaf. The black frass is deposited in the gallery without any 

 order, and is deposited differently in different mines ; usually it does 

 not much more than half fill the gallery, sometimes it almost does so, 

 the mine at the same time often being narrower and shorter than usual, 

 and coming very near the mine of N. luteella. The irregularity 

 appears to depend on the nature of the leaves, for it will be found 

 that the latter are appreciably thinner, and their network of veinlets 

 more open where the gallery is only half filled, than where it is more 

 completely filled (Wood). Threlfall says that " the mine is filled with 

 brown excrement," but Douglas remarks that the mine is filled with 

 brown excrement in the latter half of the mine only, the excrement 

 being greenish-grey in the central portion. Heinemann notes that 

 the mine is rather broad, tortuous, with a loose excremental track in 

 the middle. Frey writes : " Die Mine ist ein massig langer unci gewun- 

 dener schmaler Gang, welcher von der breiten, braunlichen Kothlinie 

 ganzlich erfiillt ist (Die Tineen, etc., p. 387). 



Larva. — The larva is bright yellow in colour, with a brown head, 

 and distinctly green dorsal vessel. It mines with the venter up, and 

 thus shows distinctly the ventral cord which forms a chain of 

 inconspicuous, linear markings. There is a superficial skin mark on 

 the venter of the prothorax, this spot and the ventral cord being 

 brown in colour, not black as in the larva of N. di.stingimida. Frey 

 says : " The larva is 2 lines in length. It is very dirty yellow in 

 colour, with a darker alimentary canal showing through. It has a 

 light brown head." 



Cocoon. — The cocoons (4) average 2-25 mm. in length and 1-75 mm. 

 in width. There appears to be some variation in shape, one of the 

 cocoons being somewhat of the typical " mussel " shape, the others 

 rather oblong-oval in outline, one particularly so. There is a some- 

 what flattened flange at the wider end, from which the dome-shaped 

 portion rises gradually, at the other end more rapidly. The raised 

 portion is red-brown in colour, the flange ochreous. The surface is 

 somewhat smooth on the raised portion, rougher, and covered with 

 loose, flossy pale silk along the flanged edge. [Described June 15th, 

 1898, under a two-thirds lens, from cocoons sent by Dr. Wood.] 

 Wood says : " The cocoon is usually spun up on the surface of the 

 ground, and is brownish-ochreous in colour." Frey describes it as : 

 " Langlich rund, ockerfarben, ziemlich flach und glatt." Heinemann 

 notes it as being " yellowish-brown, flat, generally rather broader at 

 one end." Cocoons received from Fletcher, made by larva? that had 

 fed on B. nana, are somewhat yellower and brighter in colour than 

 those received from Wood, but otherwise, in form, structure, and general 

 appearance, they appear to be identical. 



