358 MEGABISTON; BISTON. By L. B. Pkout. - ' 



B. H i n d t i b i a with 4 spurs (Acanthocampa Dyar): 



excavate/. Z. excavata Dyar. (= ? albofasciaria Matsumura iiec Leech). Evidently similar to juglansiwria but larger, 



apex of hindwing more acute, abdomen relatively smaller. Greyish white suffused with fuscous, the red mar- 

 kings more brown, the white band apparently less sharply expressed, antemedian line more bent. Larva green 

 the thorax and last 5 or 6 abdominal segments broAvn dorsally, some white streaks; thorns white at base, 

 dark at tip, not rosy. On Morus alba. Japan. 



114. Genus : Meg'abistoii Wan. 



Close to Lycia and Biston in structure. Shape and markings more as in Phigalia (J, though the apex 

 of both wings is rather more pointed, especially in the 2. Antemia in (^ strongly plumose, as in Nyssiodes. 

 Tongue slight. Hindtibia (as in most Biston) somewhat swollen distally, with 4 approximated spurs. Cells 

 less long than in most of the group. Larva with head bilobed, body nearly smooth, but with very small raised 

 white elliptical spots on the first 6 abdominal segments, resembling Tachinid eggs. Only one species known. 



plumosaria. M. plutTiosaria Leech (= dorriesiaria Warr. nee Chr., tendinosaria Dyar nee Breni.) (19 f). "Whitish, 



more or less densely dark dusted, the $$ on an average paler, but both sexes variable. Lines of forewing 

 thickest and deepest black in posterior half, approximated between median and subniedian veins. Larva wood- 

 colour, with numerous minute black or brown rings, mostly containing white central dots. On Thea chinensis. 

 Japan. 



115. Genus : Bistoil Leach. 



Head and body less densely hairy than in Lycia. Tongue sometimes well developed. ^ antenna less 

 plumose. Hindtibia usually with all spurs. Wings more densely scaled than in Lycia, ground-colour usually 

 white; forewing usually more elongate. Larva with protuberances, at least on the 5th abdominal segment; 

 head rather large, face flat, crown notched. Palearctic, Lido- Australian and Nearctic. The type species, stra- 

 taria Hufn., is nearer to Lycia than the other species, agreeing in the more hairy face, weak tongue and the 

 2-spurred hind-tibia, and is also exceptional in having the (^ antenna bipectinate to the apex; but the scaling 

 and general aspect and the larva seem to show that Gtjenees generic division (here followed) is more natural 

 than Lederers. 



nitobei. B. tlitobei Matsumura (= tripartita Wilem., moltrechti Ob.) (19 f.) may be placed here provisionally, 



but probably requires a new genus. Breast as densely hairy as in Lycia, abdomen less so; hindtibia with 4 

 approximated spurs; forewing with distal margin crenulate, call longer posteriorly than anteriorly, hindwing 

 with 2rd radial better developed than usual. Very distinct in the sharp division of the forewing into 3 areas 

 by fine black lines, the antemedian straight. Japan and Sidemi (Manchuria). 



strataria. B. strataWa Hufn. (= prodromaria Schiff., marmorata Sulz.) (19 f, g). A handsome species, very 



distinct from the following in the longer, narrow hindwing, the brown bands, etc., as well as in the structure. 



icrrarim. In -the name-type the ground-colour remains white, coarsely dusted with black. — ab. terrarius Weymer 



(= octodurensis Favre, breigneti Brascassat) has the white areas suffused with yellow-grey, the brown bands 



robiniaria. wanting, the black lines distinct. Thus transitional towards the following. — ab. robiniaria Frings (= nigri- 



meridwria- cans Oh.) is almost uniform blackish. — meridionalis Oh. from S. Frafice is white with sparser dark dusting 



and paler brown bands. — Larva twig-like, with pairs of protuberances on several of the segments, those on 



the 5th abdominal largest; variable, grey, brown or mottled. On oak, birch and many other trees. The pupa 



hibernates. Moth in March and April, at rest on tree-trunks by day. Central and parts of Southern Europe: 



herefmdi. Asia Minor; Transcaucasia. — ■ hybr. herefordi (!) Tutt (strataria ^ x betularia $), so far as yet known, lacks 



the definete brown bands of strataria and is intermediate towards betularia. 



betularia. B. betularia L. ( = p-graecum Poda) (19 g). White, with black lines and cell-marks and coarse blackish 



carbonaria. dusting. $ larger (often much larger) than (^. — ab. carbonaria Jordan (= doubledayaria Mill., nigra Heyl.) 

 (19 g). Black with a white dot at base of forewing and a few white scales in costal area of hindwing. Men- 

 insularia. delian form which is supplanting the type, especially in manufacturing districts. — ab. insularia Th.-Mieg 

 is a much rarer, intermediate form, the white ground-colour heavily dotted and mottled with black. — ab. 

 funebraria. funebraria Lamhill. is a modification of carbonaria in which the costal margin of the hindwing remains pure 

 ochrearia. white, traversed by 2 black lines. — ab. ochrearia Ma.nsbridge has the ground-colour ochraceous instead of 

 fascictia. white. — ab. fasciata ab. wow., has a grey median band crossing both wings (see Aigner-Abafi, Ann. Mus. Hungar. 

 lumosarius. vol. 4, p. 527). — fumosarius Al'ph. Ground-colour smoky, the dusting black. Transcaucasia, as a local race. 

 Unknown to me, perhaps a variety of cognataria with the lines obsolete. — Larva firm, twig-like, with a pro- 

 jection on each side of the 5th abdominal segment. Very variable in colour, green, brown or purplish, etc.. 



