OPORINIA. By L. B. Prout. 195 



A very natural genus, the species all closely related and often difficult to distinguish. Lederer merged 

 it in his Cidnria and IVlEVRrcK (scarcely less happily) in Asthcna. The smooth, flat face distinguishes it from 

 the Cidarid' group, the strongly hiangulate discocellulars of the hindwing from Asthena. Those systematisls 

 who have recognized it have usually called it Epirrita (Ifbn., Tent.) or Oporabia (Steph). 



0. dilutata Schiff. (= inscriptata Don., neglecLata Weaver) (9 f), the name-type of the genus, is probably dilututa. 

 the commonest species in Central Europe, though further north and east it is largely supplanted by uutmnnata. 

 cf antennal joints projecting anteriorly, the antenna thus appearing thicker than in cf autumiiata ; cf genitalia ' 

 vi\\h a hook on the harpes. Wings dirty white, with somewhat of a yellowish tinge, less strongly glossy than 

 Ihose of autiimnata. Forewing with numerous waved dark lines of varying distinctness, those of the median 

 area grouping themselves into 2 proximal and 3 distal; each group somewhat fiUed-in with brown shading, 

 but rarely so sharply differentiated as in autumnnta; subbasal line rather thick, gently curved or more strongly 

 bent but rarely with the acute angle of aitfuniuata; antemedian strongly excurved in aiiddle, rather irregular: 

 postmedian (i. e., the first and usually the finest and blackest of the three) very irregularly formed, generally 

 passing very near or almost touching the discal spot; discal spot rather large, especially in the ?, sometimes 

 in this sex forming a small pale-centred ring. Hindwing with lines in distal part only (in pale specimens 

 almost obsolete), running parallel with the distal margin, but somewhat lunulate-dentate. Under surface more 

 weakly marked. Very variable, though perhaps less extraordinarily so than autumnata; the ?? often more 

 sharply marked than the cfcf . The type form is somewhat greyish with the markings moderately well expressed. 

 1 have earlier (Ent. Rec. vol. IJ, p. 121) suggested a more minute subdivision, but do not consider it necessary 

 to reproduce it here. — ab. obscurata Stgr. has the ground-colour infuscated but with the parts which are obscurala. 

 normally whitest remaining somewhat paler and the bands still discernible in darker fuscous. It occurs in 

 many (perhaps all) localities with the type and is the commonest form in many parts of England. — ab. melana melana. 

 Prout is an extreme development which I have only seen from the neighbourhood of London and the manu- 

 facturing towns of the IVIidlands and the North of England. Forewing unicolorous glossy blackish, hindwing 

 also more or less infuscated. I believe it has been recorded from some German localities under the erroneous 

 name of ab. schneideri. — ab. fitnbriata Haw. is a curious and uncommon form in which the markings of the fimbriata. 

 median area are almost or altogether obliterated while those of the terminal area remain darkened, suggesting 

 a dark border. I possess one English example. — ab. pallida Prout is the whitest form, usually with the lines pallida. 

 well expressed. It is often confused with christyi and autumnata but may be distinguished by the characters 

 given above, especially the course of the postmedian line and the larger discal spot. — ab. tectata Fuchs tectata. 

 {= unicolorata Lambill). This name may be employed to denote all the non-melanotic forms in which the 

 transverse lines are entirely or almost entirely effaced. Fuchs described it as "lighter or darker grey-brown, 

 sometimes with yellowish tinge, uniform, without markings" and would possibly have included ab. melana 

 with it. He bred it from Acer monspessulanum in the Rheingau, but also took it in oak-woods. Lambillion, 

 in Belgium, obtained a rather lighter form ("uniform whitish grey"). — ab. coarctata Prout has the median coarctata. 

 area of the forewing much narrowed, the groups of lines which bound it being closely approximated. — 

 ab. latifasciata Prout (= bicinctata Fui-hs) is a handsome form with the basal and median areas of the fore- Mifasciata. 

 wing filled up with fuscous, the ground-colour remaining pale, with the normal transverse lines. — ab. pre- precursaria. 

 cursaria Greys, is an unimportant aberration, rather small and narrow-winged, dirty brownish, the outer line 

 ot the hindwing (on account of its narrower shape) running more as in autumnata tiian in typical dilutata. — 

 Egg glossy, with shallow pitting. Larva stout, rather bright velvety green, very commonly with a red or purple 

 dorsal pattern which varies much in extent. It feeds on oak, elm, hawthorn and many other trees and is 

 usually full-fed about the end of IVIay. The moth appears in October and November, or earlier in northern 

 localities. It is plentiful in Central Europe, but I have very little authentic information as to its wider dis- 

 tribution. The material which I have received or examined from more northerly and easterly localities (Scandi- 

 navia, Russia, Uliassutai) has nearly always proved to belong to autumnata. I have, however, one typical ? 

 dilutata labelled North Finland (correctly?). 



0. christyi Prout (9f) agrees almost entirely in structure with dihdata and was at first regarded as a christyi. 

 form of it, but Mr. Allen, who has given years of careful study to the subject, has shown it to be a distinct 

 species. The genitalia nearly agree but the 8"" abdominal segment in the cf shows a constant distinction; at the 

 posterior extremity of the ventral side of this segment there are in both species two points or small projections but 

 the distance between these is much wider in dilututa thau in christiji, irrespective of the size of the specimens. 

 The reader is referred for full details to "The Entomologist's Record", vol. 23, p. 79—82. cf antenna nearly as ' 

 in dilutata, the projections perhaps slightly less strong. Wings rather more glossy than in dilutata, but less 

 strongly than in autumnata, yellowish white or very pale greyish, the transverse lines generally weak (at least 

 in the cf), the antemedian in the ? sometimes more strongly expressed than the postmedian, both distinctly 

 darkened costally and marked with black on the median vein and at the origin of the 3'''' radial and 1^' median 

 branches; subbasal line in cf not angulated; postmedian lines formed nearly as in autumnata but with the 



