DIETTA. 89 
shape inversed. Labiwm coriaceous, elongate, narrow, constricted at the middle, anteriorly deeply bifid, 
with the extremities truncate. Lingua membranaceous, broadly bifid anteriorly. Prosternum rather 
small, carinated, with the carina produced behind the coxe into a subtriangular point depressed in the 
middle; episterna small and very narrow ; epimera moderate, enclosing the coxal cavities behind ; 
coxal cavities pyriform, with a trochantin at the outer extremities. Mesosternum rather large, very deeply 
excavated in front, with four oval impressions on the margin of the excavation ; episterna humeral, very 
large ; epimera rather large, extending to the coxal cavities; coxal cavities very oblique, pyriform, 
extending far into the metasternum, with a trochantin at the outer extremity. Metasternum very short, 
not extending to the sides, produced posteriorly into a point between the coxe; episterna rather short ; 
epimera extending beyond the episterna as far as the cox; cox very large and broad, not extending to 
the sides of the body. Venter composed of six segments, with the basal segment the longest, and the 
apical one very small. Leys rather long and slender, the intermediate pair the longest: anterior shorter 
than the others; tibie dilated towards the apex, and armed with two long spurs at the inner angle ; 
tarsi long, 5-jointed, 1 very small, 2-4 equal, the claws long, obtusely dentate at the base; intermediate 
femora very long; tibis slightly incurved, dilated towards the apex, densely setose, armed with spines on 
the outer side and two long, incurved, aciculated apical spurs on the inner side; tarsi similar to the anterior ; 
posterior femora obtusely dentate on the inner side of the apex ; tibie rather long, densely setose, armed with 
several long spurs at the apex; tarsi like the foregoing. Coxe: anterior small, prominent, obliquely 
pyriform, nearly contingent ; intermediate widely separated, prominent, pyriform, very oblique ; posterior 
contingent, very large, and very broad, nearly extending to the sides of the body. 
Dietta is the most abnormal of all the “ Anisotomina”; in the shape of its head and 
thorax it bears much resemblance to the Staphylinide, while the unusual development 
of its pectoral region and the position and shape of the intermediate coxal cavities 
reminds one of the Necrophort. Its proper position in the Anisotomina, to which it 
undoubtedly belongs, appears to be at the end of the tribe, leading to the true 
“ Silphina.” 
Dr. Sharp has described the anterior tarsus of Dietta as possessing but four joints, 
while in the present example there are evidently five ; but I do not think this a matter 
of much importance, because the basal joint is so small and is so completely concealed 
by the spurs of the tibia that it is undiscernible without dissection ; and moreover, since 
throughout the whole tribe the number of the tarsal joints is subject to such endless 
variation in the sexes as well as the species, the difference, if it should exist, may 
possibly be merely sexual. 
This genus has hitherto contained but a single species from N.W. Australia; 
a second from the State of Panama is now added. 
1. Dietta sharpi, sp. n. (Tab. III. fig. 8.) 
Forsan subcontractilis, elongata, capite atque pronoto angustioribus, elytris sat inflatis, rufa, nitidissima; capite 
valde prominente, magno, lato, convexo, remote punctato; oculis permagnis, valde prominentibus ; ore 
magno, prominente, labro setoso, profunde emarginato; pronoto obcordato, quam caput longiore, vix latiore, 
ante medium latissimo, valde convexo, glabro, nitidissimo, lateribus marginatis et’ rotundatis, margine 
basali leviter rotundata basi elytrorum incumbente, angulis rotundatis ; elytris quam caput atque pronotum 
brevioribus, sed multo latioribus, prope media latissimis, sat inflatis, profunde punctato-striatis, interstitiis 
glabris, nitidis, valde elevatis, humeris externe abrupte elevatis et levigatis, atque lateraliter angulatis, seta 
longa flava, erecta ad humeros, atque setis nonnullis minoribus ad latera instructis, stria suturali profunda 
impressis, lateribus sat late marginatis, angulis subhumeralibus obsoletis ; pedibus longis sat robustis, rufis, 
BIOL. CENTR.-AMER., Coleopt., Vol. II. Pt. 1, December 1887. N* 
