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ORTHOLITHA. By L. B. Prout. 



6. Genus: Ortholitha Hhn. 



Face rough-scaled, with a small projecting cone. Palpus of moderate length, rough-scaled, the terminal 

 joint small. Antenna in cf usually bipectinate. Hindtibia with all spurs. Metathorax scarcely crested. Abdomen 

 not crested. Forewing moderately broad, apex usually pointed, areole double, P' radial arising from apex of 

 cell or shortly stalked with 3'''' to 5"^ subcostals. Hindwing with costal margin long, cell rather short, 

 discocellulars oblique, not biangulate, neuration normal. — Larva of moderate proportions or rather stout, 

 nearly cylindrical or somewhat flattened, rugose laterally, tubercles and setae often strong. Feeds on low 

 plants and hibernates. The moths are night-fliers, indeed some of the best-known species are active later at 

 night than most of the Geometridae, but they are very easily disturbed by day, generally flying a short 

 distance and settling again. 



Ortholitha is chiefly Palearctic and African, but is not a very sharply- defined genus, scarcely differing 

 from Cidaiia except in the elongate costal margin of the hindwing. It is strange that Staudinger and Lederer 

 separate them by a number of unrelated genera and that Guenee refers his Euholia ( = Ortholitha) to a separate 

 subfamily, Eubolidae. Walther considers that the structure of the palpi is also distinctive in Ortholitha, but 

 some of the other related genera seem to me to approach it quite closely. 



A. cf antenna bipectinate. 



coarctaria. 0. coarctaria Schiff. (6h). Grey, dusted with brown; the lines brown, rather straight, the postmedian 



without any distal projection in the middle; median area not darkened, except sometimes between the 2 (or 

 3) lines which form its distal boundary (the postmedian lines). Cell-dot minute, often wanting. An apical 

 oblique streak present, as in most species of the genus, but often weak. Hindwing very weakly marked. — 

 mpuscata. ^- infuscata Stgr. is much darker, smoky brown but with some paler transverse stripes remaining, particularly 

 in the distal area.- It seems to be the prevailing form about Hamburg, in Jutland and again in the St. 



lenebraria. Petersburg district. — ab. tenebraria liba. is a more extreme development, almost unicolorous smoke-brown 

 or fuscous, with only the subterminal paler. It occurs occasionally with the preceding. — The life history 

 has been well worked out by Brants. Egg oval, glossy, with very weak reticulation. Larva nearly cylindrical, 

 slightly tapering anteriorly and posteriorly; head rather small, rounded, somewhat flattened in front; body 

 yellowish grey with interrupted darker dorsal line, whitish lateral stripe and small dark spots behind the 

 spiracles. Feeds on species of Genista, Sarothamnus and in captivity other Papilionaceous plants; undergoes 

 4 moults and is full-fed in 2 — 3 months. Pupa blackish brown, with long conical cremasler. The moth flies 

 in May and June, with a partial second generation in August and is local on chalk soil in Central Europe 

 and Asia Minor. Its habits are similar to those of nmcronafa, but it flies more wildly. 



nmhrifera 

 nigrescens. 



nnicronata. 0. mucronata 6'c. ( = plumbaria i^. = palumbaria Schiff. = turturia Tr.) (6i) is larger than coarctaria, 



with which it nearly agrees in the straight or only very slightly curved postmedian line; but this line is single 

 (at most only accompanied by some vague shading proximally), the discal dot is distinct, often rather large, 

 the distal area almost always weakly marked and the colouring somewhat different, the ground-colour usually 

 with a tinge of violet, the lines bright rust-colour or yellowish. Exceedingly variable. — English specimens 

 often show some dark shading proximally to the postmedian line, but Guenee was in error in regarding this 

 form as a local race; I name the form, ab. umbrifera ah. nov. — ab. nigrescens Ckll. (= obscuraria Rothle 

 = luridaria- Bkh., Guen., nee Brahm) has the ground-colour of the forewing uniformly blackish grey, only the 

 luridata. subterminal line usually remaining pale; lines as in the type form. Hindwing also darkened. — ab. luridata 

 Hufn. and Rott. (= duponti Th.-Mieg) is a less extreme aberration, only the area between the two lines being 

 blackish grey, thus forming a distinct dark median band. As Brahm changed the name luridata to luridaria 

 in 1791, I consider luridaria Bkh. (1794) a homonym and have replaced it by nigrescens Ckll.; Gillmer confused 

 the two forms. — ab. extradentata ab. nov. has the ground-colour normal, but differs from the type in having 

 a conspicuous dark, dentate line in the distal area of the forewing, preceding the pale subterminal. Described 

 by Gauckler (Ent. Nachrichten vol. 26, p. 372) but not named. It occurs occasionally in many localities. — 



pallidaria. ab. pallidaria Lambill. is smaller, the ground-colour of both wings whitish grey, the antemedian and postmedian 

 lines of forewing well marked. — ab. approximata ab. nov. has the median area of the forewing greatly 

 narrowed, the lines being placed close together. I have seen very few examples. — The egg is a rather 

 flattened oval, with large oval depression on the upper surface and with a hexagonal reticulation which 

 becomes much finer around the micropyle; colour pale yellow. The larva feeds on Ulex, Cytisus and species 

 of Genista; it is of moderate thickness, with conspicuous fold, and bears a few short stiff bristles ; the ground- 

 colour varies, being sometimes almost uniform whitish grey, darkened sometimes with niimerous longitudinal 



extra- 

 dentata. 



approxi- 

 mata. 



