HETEROCERIDZ. 773 
slight ; the European species is also usually more black in colour beneath; both 
possess a femoral line on the metasternum. 
1(s). Heterocerus vilis. 
Minor, angustulus, sordide testaceus, opacus, omnino subtilissime punctulatus; prothorace rufescente, basin 
versus plus minusve infuscato; elytris vage fusco signatis. 
Long. vix 4 millim. 
Hab. North America, Arizona (Morrison).—Mexico, Northern Sonora (Morrison), 
Yautepec in Morelos (Lohr). 
A very obscure insect apparently closely allied to H. mexicanus, but rather smaller 
and narrower, with still finer sculpture, and with the pronotum in part, if not entirely, 
red; the marks of the elytra are indefinite and also variable in their extent; and the 
legs are entirely yellow. There is a fine basal margin on each side of the thorax, and 
a femoral line on the metasternum. I do not observe any sexual distinctions. 
3 (a). Heterocerus velutinus. 
Latiusculus, niger, elytris signaturis testaceis parvis, pedibus fusco-testaceis ; opacus, omnino subtilissime 
punctulatus, densius griseo-pilosus. 
Long. 4-5 millim. 
Hab. Mexico, near the city ({ége). 
Broader than H. simplex, and distinguished by the excessively fine sculpture and dense 
griseous pubescence, by the small size of the yellow marks, and by the black antennz. 
The yellow marginal band of the wing-cases is extremely slender, and gives off near the 
base a slender branch directed obliquely backwards; the other yellow marks are situated 
as usual, but are very slender ; usually there is a yellow spot at the base on each side of 
the scutellum, but this spot is occasionally almost or quite absent; and sometimes the 
other yellow marks can be scarcely detected. There is an extremely fine basal margin 
on each side of the thorax, but no femoral line on the metasternum. The male has the 
mandibles longer and angulate externally, and the elongate labrum abruptly narrowed 
about the middle of its length. 
3 (s). Heterocerus cognatus. 
Sat elongatus, subparallelus, flavescens, pectore, capite, prothorace elytrisque fuscis, his signaturis transversis, 
magnis, testaceis ; subtilissime punctulatus, brevissime griseo-pilosus, opacus. 
Long. 44-5} millim. 
Hab. Mexico, Manzanillo in Michoacan (fHége). 
This insect is very similar to H. mexicanus, but is rather larger, and there is no 
femoral line on the metasternum; it resembles still more closely the European 
H. femoralis, but is of rather more elongate form, and the legs are clear yellow. There 
is an excessively fine basal margin on each side of the prothorax; the lateral margin 
of the elytra is rather broadly yellow, and the yellow irregular transverse marks are 
