268 



HYDRELIA. By L. B. Prout. 



black marginal strokes. Forewing beneath light grey with dark marginal strokes; hindwing whiter, the disoal 

 dot stronger than above, some indistinct lines beyond. According to the figure, the upper surface of the 

 forewing shows a tendency to the darkening of Ihe S"^ radial and 1" median veins at their origin, as in 

 Venusia cambrica. 



testaceata; ash-grey, darker mixed, the lines represented by 



scarcely indicated in the interspaces; marginal dashes (lunules) 



y narrow, formed about as in Venusia cambrica; according to 



line is also discernible, shaped about as in cambrica. At the 



become a little better expressed. Discal dot present on both 



trace of lines; hindwing greyish white, the dark vein-dots not 



The figure recalls some aberrations of cambrica; perhaps it 



testaceata. 



yoodwini. 

 i»,ie)-media. 



musciilata. H. musculata Sfp: Rather larger than 



numerous dark dots and dashes on the veins, 

 sharply black. Median clear space of forewini 

 the figure, the anterior half of the postmedian 

 inner margin of the hindwing also the lines 

 wings. Forewing beneath yellow-grey, without 

 connected into lines. Sutschan district, Ussuri. 

 is really a Discoloxia near conisaria Hmps. 



H. testaceata Don. (= sylvata Schiff. nee Scop.) (10 g) is the type of the genus and one of the two 

 species which reach the Western Palearctic Region. Rather broad-winged, dirty white or whitish grey with 

 the principal lines of the forewing brown. Variable in the expression of the discal dots, which are sometimes 

 almost eniirely wanting. — ab. goodwini Bankes is a very dark form from Kent, densely dusted with grey, 

 usually with the brown markings still well visible, but culminating in almost complete melanism. — ab. inter- 

 media Bankes has the dark dusting also stronger than in the type form but not altogether obscuring the whitish 

 ground-colour; the brown lines more strongly pronounced than in the type. It occurs together with the pre- 

 ceding aberration. — Larva stout, tapering at each end; head bifid, dark brown; prothorax with horny dark 

 brown plate; purplish brown, the thorax and last five abdominal segments greenish to green; 5"^ abdominal 

 with yellow lateral spot; dorsal line and some V-shaped dorsal markings white. On alder, birch, sallow, etc. 

 Pupa stout, very glossy, greenish brown, hibernating. The moth flies in June and is found in Central Europe, 

 S. E. Siberia and Japan. 



bicauliaia. H. bicauliata spec. nov. (12 c). At first glance very similar to testaceata, forewing slightly narrower, 



distal margin more oblique, hindwing with distal margin subcrenulate, slightly prominent at 3"^ radial, both 

 wings with P' median well stalked ; areole rather small, 1" subcostal from its apex, 5"" arising from the stalk 

 of 2"''— 4"". Ground-colour white, as in the lightest testaceata or on the forewing (especially in costal half) 

 more strongly brown-dusted; postmedian line more distinct, more sinuous, the brown band-like shading which 

 follows only reaching from costal margin to 1" median. Hindwing with little dusting, the lines rather fine 

 and sharp. Forewing beneath suffused with smoky brown; hindwing v/hite, with the lines nearly as above. 

 Japan, without more exact locality, 1 ? from the Pryer collection, in coll. Brit. Mus. 



latsaria. H. latsaria Ob. (10 g) is unknown to me, but according to the figure is certainly not the same as 



phasma Btlr. Rather darker brown-grey than testaceata, forewing slightly more elongate, the lines straight, 

 distal area with a black-brown patch between the Z"^ radial and P' median, reaching from postmedian line to 

 near distal margin. Ta-chien-lu. 



undularia. H. undlllaria Leech (described as Venusia). Larger than testaceata, forewing with costal margin more 



arched, more elongate, distal margin more oblique, apex consequently sharper, hindwing with distal margin 

 sinuous, appreciable incurved between the radials. Ground-colour violet-grey, forewing thickly irrorated with 

 dark brown; lines dark brown, the proximal ones more oblique than in testaceata, postmedian much more 

 dentate, with strong projecting tooth at P' radial, the brighter brown band-like area which follows, and also 

 the distal lines, much more strongly projecting outwards in the middle. Hindwing with similar dilferences. 

 Forewing beneath more infuscated, hindwing with the lines broad. Pu-tsu-fong. 



tchrinaria. H. tchrinaria Ob. (13 d) was described as an Ephyra but the neuration, as figured, and also the general 



habitus seem to show it belongs to ihe Hydrelia group; should it be found that the areole is double it would 

 be removed to Asthena. Rather narrower-winged than any of the preceding Hydrelia, length of forewing as 

 in a large testaceata, rather uniform violet-grey, forewing with a whitish spot at the distal margin of the 

 3'''' discocellular, the dark lines feeble, outcurved, becoming nearly vertical at hindmargin, the postmedian the 

 best expressed; fringe chequered. Underside more glossy grey, with broad curved postmedian line, accompanied 

 proximally by a pale line. Ta-chien-lu and Mou-pin. 



chionata. H. chionata Led. (^ quadri punctata Bienert) (13 e). Very distinct in its shining snow-white wings 



with sharply black discal dots and all the markings suppressed except a strong outcurved brown grey ante- 

 median Une on forewing only and a sinuous postmedian on each wing. Forewing broad, rounded, the distal 

 margin with minute but distinct black dots. Hindwing moderately long, with distal margin strongly convex, 

 slightly prominent but less so than in Asthena albulata, of which Staudinger — overlooking the neuration and 

 other characters — has suggested it may be a variety; terminal dots wholly or in part obsolete. Southern 

 Transcaucasia and North Persia. 



