NEPTICULA ASSIMILELLA. 351 



beide sind von Wien [Zeller, Linnaea Entomologica, vol. iii. (1848), 

 pp. 327-328] . 



Imago. — Head ferruginous. Anterior wings 4-5 mm. ; fuscous in 

 colour, the base whitish ; a whitish spot on the disc, and two opposite 

 whitish spots towards outer margin ; cilia very pale grey, with whitish 

 tips. Posterior wings and cilia grey. 



Comparison of N. assimilella with its allies. — Although this 

 species exhibits some variation in the size and distinctness of the 

 whitish spots, it is not difficult to distinguish the different forms from 

 the allied species, only two of which, N. trimaculella and N. subbi- 

 maculella, are likely to be confused with it. From the former the 

 male may be separated by the dark colour of the body, legs and hind- 

 wings. Besides this, the head-hairs in N. assimilella are red, in 

 N. trimaculella ochreous-yellow, the eyecaps purer white, and the 

 epaulettes of the blackish dorsal-plate bordered with white, whilst the 

 latter, in N. trimaculella, remain pale. In A T . trimaculella, also, the 

 longitudinal basal streak extends to the base of the wing, whilst in 

 N. assimilella the spot is much smaller, rounder, and separated from 

 the base by a portion of the black wing. In N. assimilella the opposite 

 spots are placed somewhat obliquely, and the fringes lack the yellowish 

 tinge which occurs in N. trimaculella (Frey). 



Egg-laying.— Judging by my series, the egg is laid generally on 

 the upperside of the leaf, close to the midrib, more rarely to one of 

 the lateral ribs (Fletcher). Always laid on the upperside (Nolcken). 



Mine. — The mine is irregular, but often strongly twisted, fine at 

 its commencement, and filled with a dark frass-line ; then it becomes 

 considerably broader, at the termination, being often 2'" in breadth ; 

 the frass in this last portion forming a somewhat fine and broken 

 thread. Nolcken has recorded as many as 15 mines in one leaf, and 

 says that the mine is characterised by the chalky-white, closely- 

 twisted spot at the commencement of the mine. The latter widens 

 rapidly, and •becomes blotch-like, the windings lying close to one 

 another, and without any partitions of the leaf-substance between. It 

 is at first greenish-coloured, but then becomes more or less brownish- 

 yellow. In no other species has such an inconspicuous frass-line been 

 noticed, nor one of such small bulk. The frass-line commences as an 

 exceedingly fine broken thread, with comparatively broad pale margins, 

 which gradually increase still more. In the second portion it becomes 

 more granular, but remains broken, and consists of little heaps, that 

 approximately indicate the path of the larva, and which, in the strongly 

 marked windings of the now broad mine, is somewhat difficult to trace. 

 Frequently the frass lies about irregularly, and without arrangement, 

 but always sparingly. The exit is always on the upper surface of the 

 leaf. 



Larva. — The larva is yellow in colour ; head pale brown ; the 

 cephalic ganglia brown, rather darker than head ; ventral chain 

 invisible ; abdominal canal green in front, yellow behind. Mines 

 with the dorsum uppermost (Wood). Frey says that the larva is very 

 similar to that of N. trimaculella. Nolcken describes the larva as 

 lighter or darker wax-yellow, with reddish yellow-brown intestinal 

 canal showing through the skin, the head brown. 



Cocoon. — The cocoons (4) examined vary in shape and colour, one 

 is dark brown, the others purplish-black ; the dark brown one forms a 



