276 
HORN EXPEDITION—OOLEOPTERA. 
they might pass for a single species, but they present ditferences on close 
examination which are quite inconsistent with such a supposition. All the species 
of Nyctozoilus are rare in collections. I cannot find in the somewhat numerous 
published descriptions of and notes on the species of the genus any satisfactory 
indication of the sexual characters, probably because no one has been in possession 
of so many conspecific examples as to be able to spare any for dissection, so as to 
determine the sexes indisputably. After examining a good many specimens (but 
unfortunately not more than three of any one species) I have satisfied myself that 
well-defined external sexual chai’acters are wanting, and that the males are only to 
be distinguished from the females (unless it be vice versa) by their narrower and 
more elongate form. One’s first impression on looking for sexual characters is 
that the presence of tomentosity on the legs is a mark of the male, but I believe 
this to be a specific character. I have of several species two examples of the 
specific identity of which I do not think doubt is possible, one of which is 
considerably narrower and more elongate than the other \ but in every such 
instance thei’e is similar tomentosity (if any) on the legs of both. I find the most 
available characters for specifying the distinctive features of closely-allied species 
in the antenna?. 
N. crassicornis, sp. nov. (2). Opacus, partibus elevatis sat nitidis, corpore 
subtus pedilmsque nitidis; niger, antennis pedibusque picescentibus; capite 
puncturis obsoletis sat subtilibus subcrebre impresso; oculorum orbitu sat 
rotundato; antennis prothoracis basin vix attingentibus, articulis 1° 2® que parvis 
(his conjunctis quam 3^** paullo brevioribus), articulis 4°-10° plus minusve per- 
foliatis, 4° quam fere duplo breviori fere transverse, 5°-6° que inter se 
longitucline sat tequalibus quam 4^® paullo brevioribus (4° 5° que conjunctis quam 
3'^*^ parum longioribus), 5° vix transverse 6° fortiter transverse, 7° 8° que inter se 
lequalibus quam G'l* brevioribus sed hand angustioribus, 9° 10° que inter se 
lequalibus quam et brevioribus et angustioribus sed fortiter transversis, 
11° obovato quam lO^’^ sat longiori; prothorace sat fortiter transverse, parum 
manifesto (fere ut caput) punctulato, antice angustato, ad latera sat late deplanato, 
marginibus lateralibus incrassatis obsolete recurvis leviter (pone medium plus 
minusve sinuatim) arcuatis, angulis posticis acutis, disco utrinque fovea magna 
leviter impresso (hac postice distincte, antice vix manifeste, impressa) ; elytris 
costis 5 (suturali inclusa) sinuatis bene elevatis nitidis sequalibus (his inter se 
irregulariter costis multis transversis similibus conjunctis) ornatis, pone scutellum 
triangulariter depressis, costarum interspatiis coriaceis paullo rugulosis ; femoribus 
tibiisque posterioribus 4 intus tomento fulvo ornatis ; prosterno inter coxas sat 
fortiter 3-sulcato. Long. 6 1. 
