1871.) 267 
This extraordinary little Bembidiide is closely allied to X. hilaris, 
and was found in a similar situation at Ega, Upper Amazons, running 
on the trunk of a felled tree. The longitudinal ribs of the thorax are 
narrow, and only the two central ribs reach the anterior and posterior 
margins. 
XYSTOSOMUS ELAPHRINUS, n. sp.—Leate ceneus, splendidus, hic illic 
viridi-tinctus, antennis palpis pedibusque piceo-rufis ; oculis maximis, sulcis 
Frontalibus elongatis, margineque juxta oculum fortiter sulcato ; thorace 
parvo, transversim quadrato, antice paulo angustato, medio vix subangulatem 
dilatato, marginibus postice sinuatis, angulis posticis productis, acutis ; supra 
paulo convexo, carina juxta angulum posticum intus curvata, basr fortiter 
oblique sulcato, linea longitudinali bast fortiter vimpresso; elytris ovatis, 
convexis, marginibus circa humeros reflexo-explanatis, supra punctato-striatis, 
stria 1™@ antice vix impressa, 2—6 ante medium evanescentibus, 3—-9 grosse 
punctatis et fortiter impressis, disco posteriori levissimo, striola recurva antice 
Sortiter hamata. Long. 1¢ lin. 
Ega. Also a remarkable species, which differs in form from the 
other species of Xystosomus, but not in its essential characters. The 
head is very similar to that of the genera Llaphrus and Notiophilus. 
Bembidium cayennense, Dej., appears to resemble it in form and 
sculpture, but it differs in several points, and I do not think the apical 
striola would have been overlooked by Dejean. 
Oxzs.—None of the Bembidiide, except of the Tachys group (Gen. Tachys, 
Pericompsus, Xystosomus, &c.), are found in-the equatorial plains 
of South America. Species of the Notaphus group are numerous 
on the Mexican plateau, and re-appear in many species in Chili. 
Liotacuys, nov. gen. (Bembidiide). 
Corpus gracile, elongatum, convexum, nitidum. Caput parvum, collo 
erasso, tumido; sulcis frontalibus latis, profundis; oculis prominentibus. 
Palpi dense pubescentes. Antenne robust, elongate, corpore paulo breviores, 
articulis 2—11 pubescentibus. Thorax cordatus, postice fortiter constrictus. 
Llytra elongato-ovalia, levissima, absque striis, stria suturali sola prope 
apicem distincta, striola recurva fortiter impressa, disco utringue punctis 
duobus setigeris. Pedes elongati, graciles, toti pubescentes ; tibice antic 
ad apicem anguste, simplices. 
The curious little insect on which this genus is founded resembles 
in form the genus Anthicus. It is well distinguished from Tachys and 
Pericompus by the long and robust antenne, which have the further 
peculiarity of being dark in colour, with the 5 terminal joints white. 
