392 Rev. H. Clark on the Halticide of South America. 
latum, ad frontem etiam fovea media; subtilissime punctatum : thorax 
levis, margine anteriori et basi marginatis: scutellum triangulare 
nitidum, impunctatum : elytra robusta, subtiliter punctata, basi late et 
plaga maxima post media (hemielytron apicale occupante, subcireu- 
lari, haud margines attinente) nigris : corpus subtus rufo-flavum ; meta- 
sterno fusco adumbrato: pedes rufo-flavi; femoribus posticis ad apices 
fuscis: antenne fusce, art. 1 et 2 rufo-flavis. 
Long. corp. lin. 33, lat. lin. 14. 
I received a specimen, in the Cheyrolat collection, from Cayenne. 
Oxygonus rubidus. 
O. e majoribus, rubidus, pedibus nigris: caput super oculos utrinque ob- 
lique, et ad medium longitudinaliter foveolatum ; puncta ad frontem 
sparsa apparent: thorax ad basin et antice marginatus: scutellwm im- 
punctatum : elytra lata, parallela, punctata : corpus subtus rufo-flavum : 
pedes nigri; femoribus basalibus rufo-flavis: antenne nigr, articulis 
apud apices flavo-annulatis. 
Long. corp. lin. 44, lat. lin. 24. 
O. rubidus is the largest known species of the genus ; it is nearly 
allied to the widely distributed species O. acutangulus, Chevr., but 
may be distinguished from it by its larger size, its specially rufous 
coloration with black legs, as well as by the medial fovea and 
sparingly arranged punctures on the head. 
I have a single example, captured by Mr. Bates at St. Paulo, on 
the Amazons. 
Oxygonus adumbratus. 
O. parallelus, robustus, flavus, elytris fusco-adumbratis: caput mter ocu- 
los utrinque oblique foveolatum, impunctatum: thorax impunctatus, 
ad basin et antice marginatus: scutellum impunctatum, flavum : elytra 
parallela, punctata (punctis minutis, et juxta apicem obsoletis), flava, 
maculis quibusdam incertis fuscis adumbrata: corpus subtus flayo- 
ferrugineum : pedes fusco-nigri; femoribus flavis: antenne rufo-fuscie, 
art. 1-3 rufo-flavis. 
Long. corp. lin. 4, lat. lin. 14. 
Nearly allied to O. acutangulus, but I believe a different species ; 
the coloration is different, and the form somewhat more depressed ; 
the markings on the elytra are irregular, and may be described as a 
dark ferrugineous shade or cloud over the whole of the middle of 
the elytra, which does not touch the margins; the thorax also is a 
trifle more transverse in form, and the whole body somewhat more 
elongate than that of O. acutangulus. 
I have an example in my collection, captured by Mr. Bates at 
Tunantins, Amazon. 
