104 CORYLOPHIDZ. 
SACIINA. 
Head more or less exposed. 
Thorax rounded at the sides, widest near the middle . Ainigmaticum. 
Front of the thorax entire . . . . . . +. + + EcrinocerHatus. 
Front of the thorax excised . . . . - « » ~ «+ CONODES. 
Head wholly concealed. 
Antenne ll-jomted . . . . . . . . es - Sacrum. 
Antenne 10-jointed . 2. . . 1. ee +) 6+) 6 ARTHROLIPS. 
JENIGMATICUM *, gen. nov. 
Body elongate-oval, with the head exserted. Head small, produced in front; eyes very large and very pro- 
minent. Thorax moderate, subcordiform. Scuéellum large, rounded at the apex. lytra entire, long, 
with the extremities separately rounded. Abdomen with the pygidium exposed. Antenne inserted near 
the eyes, 9-jointed—l1 very large, pyriform, slightly recurved, 2 oval, rather smaller than 1, 3 and 4 
small and slender, 5 much larger than 4, 6 small, same size as 4, 7-9 large and mueh incrassated, forming 
a rather loose club, of which the apical joint is the largest. Palpi: mawillary rather large, 4-jomted— 
1 very small, 2 very large, turgidly incrassate, oval, with the apex truncate, 3 and 4 forming a slender 
long point, obtuse at the apex, and furnished with short apical sets, the third joint short and transverse ; 
labial rather large, 3-jointed—1 very small, 2 very large, turgidly incrassate, oval, with the apex slightly 
truncate, 3 small and conical. Zabrum large, subquadrate, slightly rounded in front. Mandibles small 
and rather slender, with the apex much hooked and acute, furnished at the base with a subconical 
process, its front surface flat and transversely ribbed. Maille unilobed, the lobe long and rather 
broad, with its apex acute, faintly incurved, and minutely denticulate on the upper part of the edge. 
Mentum short, transverse, suboblong. Zabium short, transverse, faintly contracted at the base, with the 
anterior angles much rounded. Lingua very long and narrow, with its extremity nearly straight. 
Prosternum large, broadly produced between the coxal cavities, and much dilated behind them ; episterna 
Jong and narrow; epimera large, broadly enclosing the coxal cavities ; coxal cavities rather small, oval. 
Mesosternum rather short ; episterna moderate, humeral ; epimera short and broad, not extending to the 
coxal cavities; coxal cavities nearly circular, moderately distant. Metasternum large, not extending to 
the sides of the body, broadly produced and faintly rounded between the coxw ; episterna large and long, 
almost reaching to the coxe; epimera long and narrow, extending beyond the coxe; coxe small, 
pyriform, widely separated. Venter composed of six segments, with the first nearly as long as the other 
five united. Legs: anterior femora modcrate, the tibie simple, slightly dilated towards the apex, the tarsi 
very short, 4-jointed, with the basal joint very small, and the apical joint robust, much longer than the 
three basal joints united, the claws moderate, much curved ; intermediate similar in form to the anterior, 
but longer, with the tarsi distinctly 4-jointed ; posterior similar in form, but longer than the intermediate, - 
the femora longer and much more robust, the tarsi distinctly 4-jointed. Cove: anterior oval, moderately 
distant; intermediate rounded, moderately distant ; posterior small, pyriform, widely separated. 
This curious genus is an apt illustration of the importance of the external skeleton 
of the underside, combined with the organs of the mouth, in affording a correct clue to 
systematic arrangement. At first sight the upper surface presents but few of the 
characters usually considered to be indicative of the Corylophide, and its outward 
form seems more suggestive of relationship to either Péilium or Corticaria; and it is 
only by the anatomy of the underside of its external skeleton and of the organs of 
the mouth that its true affinities can be discovered. 
In all these points Znigmaticum is purely Corylophide, and varies but little from 
* Aiveyparcsoy, a puzzle. 
