NEPTICULA SUBBIMACULELLA. 353 



midrib, or by the side of a large lateral rib. Its longest diameter is 

 about -28 mm., its width -24 mm., and height -1 mm. The surface is 

 smooth and polished (Chapman). 



Mine. — The larva commences to mine a very slender gallery, keeping 

 close to the rib. In this mine the excrement forms a thick blackish 

 central line ; after a while, however, the larva mines in a blotch, 

 forming an oblong about half an inch long and a quarter of an inch 

 broad ; in this the excrement is rather loosely and irregularly placed. 

 When the larva is full-fed it creeps out through the upper cuticle of 

 the leaf, and proceeds in search of a convenient place in which to 

 form its cocoon (Stainton). Wood says that it is almost impossible 

 to overlook the green, roughly triangular patches in the brown oak- 

 leaves lying on the ground from September to November, in which 

 are the mines of this species. The patches usually extend from an 

 angle of the midrib for some little distance into the adjacent inter- 

 space, whilst at or near the apex is the larval blotch. The mine 

 starts from the midrib (or a lateral one) and proceeds as a fine gallery, 

 that keeps to the side of a rib. The peculiar influence exerted by the 

 larva in the preservation of that part of a leaf in which a mine is 

 placed is active during the making of the preliminary gallery ; and 

 Wood records that on August 15th, 1893 (at the hottest period of a 

 most extraordinary summer), many brown and dead oak-leaves were 

 picked up, quite shrunken and dry, except for the little patches 

 containing the mines of this species, which were not only green but 

 juicy. 



Larva. — Length 2 lines ; pale green in colour, shining, dorsal 

 vessel reddish ; head reddish, the mouth and two lines receding from 

 it darker, the prothorax with two dark brown linear scales dorsally, 

 and with a quadrangular dark patch ventrally. It is a singular fact in 

 vegetable physiology, that when leaves are turning brown, the spots 

 tenanted by these larvse remain green much longer than the remainder 

 of the leaf, and this may frequently be observed in the leaves after 

 they have fallen (Stainton). 



Cocoon. — The cocoons average about 2-5 mm. long and 1*75 mm. 

 wide. Eoughly oval in outline, with one end much wider than the 

 other ; a flattened rim round the broader end, the central and narrow 

 end rising into a flattened dome. Colour brownish, somewhat yellower 

 on the flattened rim. The cocoon moderately smooth, but with a 

 fair supply of flossy silk round the projecting edge, by which it is 

 fastened to either side of a leaf. [Described under a two-thirds lens, 

 September 9th, 1898, from cocoons sent by Mr. W. H. B. Fletcher.] 

 Stainton notes the cocoon as "pale whitish-ochreous in colour, rather 

 flat, mussel-shaped, and only slightly flossy ; the pupa protrudes its 

 anterior segments from the broader end before the emergence of the 

 imago." 



Food-plants. — Quercus robur and Q. iiedunculata. 



Time of appearance. — This species appears to be only single- 

 brooded, the imagines appearing in May and June, from larvae that 

 feed up in October-November. Milliere, however, records imagines as 

 being on the wing during December-January, at Cannes. It was 

 taken by Mann, in May, 1853, at Fiume, and Reuter captured it in the 

 I. of Aland, on May 13th, 1886. Bower captured imagines resting 

 on Iihamniis leaves, on June 1st, 1891, at Chislehurst ; we have found 



