12 E. B. Williamson and J. H. Willla.mson 



This species was associated with solutus and kakli at Villa Murtinho 

 and with attenuaUis at Porto Velho. Unfortunately no females were 

 taken and our knowledge of this sex is based on De Selys' description. 

 As to the correctness of our determination of the seven males before us as 

 cornutus there can be little or no doubt. De Selys' description of the 

 male clearly indicates the group of the genus to which our specimens be- 

 long (origin of M^a and spine on the superior appendage). No other 

 species of the group is known in the Amazon basin, and the color of the 

 stigma and detailed description of the superior appendages agree with 

 our specimens. There is no reason to doubt that the female (or females) 

 described by De Selys belonged to the same species as his male. 



2. Perilestes guianensis, new species 



Abdomen male 44-46, female 39-42; hind wing male 21.5-23, female 

 24-25; stigma front wing male 1.13-1.20, female 1.24-1.35; stigma hind 

 wing male 1.30-1.33, female 1.40-1.50; abdominal appendage male 1.30, 

 female .40 ; male anterior lamina from apex of sternum of segment 1 to 

 apex of the posterior process 1.6-1.7 ; female valve 2.3. 



Male. — Labium as in remotns; labrum, clypeus and frons brown, the 

 labrum sometimes narrowly darker along its base, anteclypeus largely 

 darker with some greenish, postclypeus darker medianally and anteriorly, 

 and frons darker at the extreme lateral margins. 



Prothorax obscure, sides pale, dorsum darker, especially on the hind 

 lobe; the proepimeron largely and the proepisternum to a lesser extent, 

 dark; hind border semicircular. 



Thorax similar to that of remotus but reddish brown largely or entirely 

 replacing the black of the latter species, except in the second lateral suture, 

 and with the following differences: the pale color on the metepisternum 

 above and anteriorly nearly or quite reaching the wing base ; the metepi- 

 meron is entirely pale, the black stripe on the second lateral suture con- 

 fined to the metepisternum and continued below across the upper edge 

 of the metinfraepistemum, thus resembling magdalenae but more reduced 

 even than in that species; no black on the latero-ventral carina and the 

 merest trace of dark on the metepimeron. Beneath pale, the sterna black. 



Mesostigmal lamina low, very slightly elevated at the point where the 

 angle occurs in that of cornutus. 



Coxae pale, unmarked. Femora pale, each slightly darker at apex 

 and with a more or less distinct postbasal dark ring and a very slightly 

 more extensive anteapical one, the two rings more or less joined along 

 the anterior row of spines. Tibiae pale. 



Venation similar to that of remotus. 



Abdomen seen from above: 1 pale, brown ringed apically; 2-6 similar 

 to those of remotus, the brown on 2 paler, duller and reduced ; 7 with an 

 ill or well defined, dull and pale postbasal area following the slightly 

 darker and more reduced basal brown, the median brown area into which 

 the postbasal pale area darkens is followed or not by an ill defined, scarcely 



