of some new Species of Geometridce. 1 13 



legs with tlie femora rather shorter than the tibiae, the latter 

 slender, snb-cyh'ndric, rather stouter at the apex than at the 

 base^ armed within, beyond the middle, with two moderately stout 

 moveable spines, and two similar ones at the apex. Tarsi longer 

 than the tibicc, similar in their structure to those of the anterior 

 pair. Abdomen short, slender, curved, the base with a cavity on 

 each side, within which may be seen a drum-like membrane. Last 

 segment, in the males at least, furnished with two broad valves, 

 lined inside with hair, and surmounted by a tuft of long hairs on 

 each side. 



The genus is divisible into three sections founded on the cha- 

 racters of the posterior wings. In the first section they are 

 elongate, caudate, externally dentate, the tail being formed by a 

 prolongation of the first and second median nervules, reminding 

 us of the hind wings of Diorhma Rhetus and its allies. 



This section seems to be confined to the more northern parts 

 of South America, as I have only seen the specimens collected 

 by Mr. Dyson. 



The second section has the posterior wings subquadrate, the 

 second and third median nervules being prolonged so as to give 

 an angular character to the outer margin. This structure re- 

 minds us of the genus Ancyluris. 



The third section has the posterior wings obovate, and in some 

 respects reminds us of Eurygona Ouranus. 



The generic details, which will be given conjointly with some 

 figures illustrative of the peculiar scales and hairs of the posterior 

 wings, are from a specimen of Erate'ma Zoraida, the only species 

 I have had an opportunity of dissecting. I may here express my 

 hope that Lepidopterologists will for the future be more careful 

 to preserve the legs of their specimens. In drawing up the 

 generic characters given above I have had considerable trouble 

 owing to want of care in this respect on the part of the collectors 

 of the specimens. 



Sect. 1. 

 Sp. 1. Er. Zoraida. 

 Er. Alis omnibus supra cervino-fuscis, anticis linea media flex- 

 uosa, transversa, alba, posticis fascia lata margineque externo 

 cinnabarinis. 

 Exp. alar. 1 unc. 7 lin. vel 40 mill. 

 Hab. Venezuela. (Tab. XII. fig. 1, 1«, 2.) 

 Head black ; the orbits of the eyes white, the palpi striped with 

 white; antennae black; thorax fawn-coloured. Anterior and 



