NEPTICULA SALICIS. 319 



margin of the leaf ; when it originates in the centre, it has a closely 

 twisted commencement, which is often absorbed later by the blotch. 



Larva. — Length 2 lines; amber-coloured, shining, the dorsal 

 vessel a little darker ; the head brown, and two brown lobes show 

 through the prothorax (Stainton). Nolcken describes the larva as 

 being of a " faint, honey-yellow tint, with very transparent, pale 

 brown head, and darker mouth-parts and sutures ; the intestinal 

 canal greenish ; on the ventral surface a row of indistinct lozenge- 

 shaped spots, very small, and joined together." Wood notes that " the 

 prothoracic markings (the equivalents of the two halves of a pro- 

 thoracic plate) are blackish, and, lying more or less over the posterior 

 lobes, help to give a specially dark appearance to the back part of the 

 head." 



Cocoon. — The cocoons examined (8) average 3 mm. in length, and 

 2 mm. in width, variable in shape, roughly oval in outline, but with 

 one end distinctly broader than the other, the long sides also being 

 slightly hollowed out in some specimens. There is no very clearly 

 denned rim, although the edge thins off and is distinctly crenate, the 

 upper portion is considerably arched, the surface rather rough and 

 covered with a thin coating of loose flossy silk, the colour varying 

 from pale straw yellow to a deep yellow inclining to orange. The 

 empty pupa-case projects from the wider end, and is quite transparent 

 and colourless, shiny and apparently very delicate. [Description made 

 July 20th, 1898, under a two-thirds lens, from cocoons sent by Mr. 

 W. H. B. Fletcher.] To the naked eye the darker cocoons are pale 

 brown in hue, the rim appearing yellowish on the edge. The lighter 

 cocoons are entirely pale yellowish. Cocoons (9) sent by Dr. Wood 

 also average 3 mm. in length and 2 mm. in width, and are also 

 variable in shape, the more regular ones forming an almost perfect 

 oval in outline. Stainton notes the cocoon as '' brownish-ochreous, 

 rather shining, somewhat mussel-shaped." Frey describes it as " dark 

 red-brown, somewhat flattened, smooth, forming a longish oval." 

 Hind says it is " rather large, brown in colour, with the broad end 

 yellowish." 



Comparison of cocoon op N. salicis with that of N. vimineti- 

 cola. — The cocoon of N. vimineticola is markedly smaller (and especi- 

 ally narrower) than that of N. salicis ; it is much thicker at its 

 narrow end ; dark brown (almost mahogany-brown) in colour, whilst 

 that of N. salicis is pale yellowish or orange in tint ; the cocoon of 

 N. vimineticola is also much more thickly covered with flossy silk than 

 is that of N. salicis. 



Food-plants. — Salix cinerea, S. caprea, S. aurita, ? S. russelliana. 



Time of appearance. — The species is double-brooded, the imago 

 appearing in April-May and July-August, from larvas that feed up in 

 September-October and July respectively. Milliere records it as 

 appearing in April, at Cannes. Atmore says that it is one of the 

 earliest species to appear, being out at King's Lynn, usually by the 

 last week of April, or first week of May, and Hodgkinson records the 

 breeding of it on April 13th, 1887, at Preston. Eeuter found it on 

 May 13th, 1876, in the I. of Aland, yet Chapman, at Redhill, did not 

 breed the insect from mines of the previous autumn until June 

 7th-l2th, 1898. Frey records the second brood as being only partial 

 nr. Zurich, in July. Stainton captured imagines on June 5th, 1849 



