GEOMETRID^. — PTYCHOPODA. 305 



wings, having therefore only three spots, as above mentioned, in heu of 

 four. 



Very local : found in the beginning of May in a wood near 

 Colney-liatch. 



Genus CCXXXV.— Ptychopoda * mihi. 



Palpi short, slender, subparallel, acute, slightly clothed with scales, triarticu- 

 late ; the basal joint curved, shorter than the second, which is attenuated ; 

 terminal elongate-ovate, obtuse : maxillw long. Antennw short, ciUated more 

 or less in the males, simple in the females : head small ; forehead depressed : 

 ei/es large, globose : thorax slender : wings entire on the hinder margin ; 

 posterior sometimes a little sinuated, placed nearly horizontally during repose, 

 all of an uniform colour, with a black point in the centre, and obscure trans- 

 verse strigae ; the hinder margin generally having a waved fascia, composed of 

 more or less confluent dots or clouds : abdomen rather long, slender, with an 

 acute tuft at the apex in the males ; short, more robust and acute in the fe- 

 males : legs rather short ; posterior tibice more or less incrassated, sometimes 

 without spurs, at others with one or two pair, and in the typical males with a 

 very long fascicle of hairs, arising at the base of the inner surface, and capable 

 of being expanded Uke a fan : posterior tarsi in some instances very short. 



The males of this genus are nearly all distinguished by some 

 peculiarity in the structure of the posterior legs : in the typical 

 species, the tibise are compressed and have a groove on the inner 

 edge, in which a large fascicle of long hairs, capable of being 

 expanded at the will of the animal, is placed ; those tibise are fre- 

 quently destitute of spurs, and the tarsi of the same legs are often 

 very much abbreviated : — some of these characters also obtain in 

 some of the following genera, but the present may be known there- 

 from by the rotundity and brevity of the wings, which are generally 

 adorned on their hinder margin by a waved fascia of dark clouds, 

 placed behind a sinuous striga. 



A. Posterior tibiae of the males without spurs; of the females with one pair at 



the apex. 



Sp. 1. dilutaria. Alts griseo-albidis, strigis duabus distantibus anticis, aliisque 



confertis limbi communibus saturatioribus. (Exp. alar. 10 — 1 1 Un.) 

 Ge. dilutaria. Hiibnerf—Vt. dilutaria. Steph. Catal. part \i. p. 151. No. 6713. 



IItuI, plica ; a-ouj, pes. 



