GKOMETRIDiE. — CHESIAS. 269 



Sp. 1. Hippocastanaria. Alis anticis argenteo-cmereis, lineis duabus obsolctis 

 nigricantibus cinereo adnatis, posticis albidis rubro mkantibus. (Exp. alar. 



1 unc. 3—4 lin.) 

 Ge. Hippocastanaria. HJbner.—V^. Hippocastanaria. Steph. Catal. part ii. 



p. 141. No. 6622. 



Head and thorax dark cinereous ; anterior wings the same, with a silvery hue, 

 with two very obsolete dusky strigae, one incurved towards the base, the other 

 behind the middle and repanded ; the former bordered anteriorly and the 

 latter posteriorly with pale cinereous ; in the centre of the disc is a rather 

 conspicuous fuscous dot, and the nervures are mostly fuscous : on the hinder 

 margin is a row of black dots ; cilia silvery-ash : posterior wings whitish, with 

 a reddish tinge, and an obsolete striga towards the hinder margin, v^hich last 

 has a row of faint dots : cilia pale immaculate. 



The female is smaller, with the wings narrower and darker, the anterior with 

 the space between the strigjE forming a conspicuous dark fascia, and the 

 posterior have an irregular dark strigose wave in the middle. 



Apparently very local : I possess two fine specimens from Roch- 

 ford in Essex, and others from the New Forest, where the insect 

 appears to be in plenty in July : it also occurs near Birch-wood, 

 and the female in my collection I captured in April on Ockham- 

 heath, near Ripley. 



Genus CCXXL— Chesias, Treitschke. 



Palpi long, projecting in form of a beak, approximating at the apex, acute, 

 densely scaly ; triarticulate, the basal joint short, slightly robust, second 

 elongate, rather slender at the base, and somewhat thickened towards the 

 apex, terminal longer than the first, ovate-lanceolate ; iiiuxiUw rather long. 

 Antennw simple in both sexes, the articulations in the males very slightly pro- 

 duced within and pubescent, a little compressed: head small; furehead 

 globose, prominent: eyes large: thorax slender: ivings entire, glossy; anterior 

 ovate-lanceolate, not distinctly fasciated; posterior oval, ample: abdomen 

 somewhat robust, stout, cylindric, obtuse, and slightly tufted at the apex: 

 kgs simple; tibi(B slender. Larva elongate, slender, naked, not tuberculate ; 

 pupa subterranean. 



From Pachycnemia, with which genus Treitschke unites the 

 present, Chesias appears to differ by the great dissimilarity in the 

 structure of the palpi (the basal joint not being so long as the apical 

 one, M^hereas in the former genus the basal joint is longer than the 

 second, and the apical one comparatively minute), combined with 

 the glossiness and dissimilar form of the wings, and by having all 

 the tibise slender. 



