Horn] —to [June 20, 



IMaiiy species of Ilister {arcuatus, Imipes, interruptus, etc.), liave uo 

 proper pectoral plate, and the aiiteniial cavity is entirely uncovered. This 

 character cannot be made use of in a systematic manner, as the transi- 

 tion is so gradual from one form to the other. 



In the last three genera, the funicle of the antennae when at rest passes 

 through an incisure between the prosternum proper and the episternum. 

 The prosternal lobe in Dendrophilus is broader and shorter than in Paro- 

 malus. 



HiSTEE, Linn. 



For convenience of study this genus may be divided into the following 

 sub-genera, some of which have been considered sufficiently well founded 

 as to have been retained as genera. In the scheme published by Dr. 

 Leconte, Proc. Acad. 1852, p. 38, they have all been united under the 

 name Hister, subsequently, Class Col. N. A. p. 7G, ritellster alone was 

 separated, at the same time doubts were expressed as to the propriety of 

 the course. 



Anterior tibiaj with the tarsal groove badly defined, 

 straight. 

 Internal marginal thoracic stria more or less distinct, 

 always entire ; mesosternum emarginate or trun- 

 cate at apex. 

 Hind tibiiB broad at base, with a single row of 



spines *. Psiloscelis. 



Hind tibias narrow at base, two rows of spines. 

 Elytral strine oblitei-ated, surface opaque, punc- 

 tured with smooth fiattened tubercles Margarinotus. 



Elytra striate Ilister. 



Internal marginal thoracic stria entirely absent ; 

 mesosternum more or less produced in front, pro- 

 sternum at tip emarginate. 

 Hind tibiio with two rows of spines ; elyti*a striate. Phelister. 



Anterior tibia} with tarsal groove Avell defined; internal ij"*/ 



marginal thoracic stria entirely absent. Middle and 

 hind tibiae dentate. 

 Anterior tibiae without tooth on inner margin ; pro- 

 sternum at apex flattened and without marginal 



line Plat'jsoma. 



Anterior tibicB with a small internal tooth near the I? l^ 



base ; prosternum convex and with marginal line... Cylistix. 



Sub-genus Psiloscelis. 

 Tliorax with two marginal striic closely approximated, the outer very 

 close to the margin. Hind tibiie scarcely narrower at base than apex, 

 strongly compressed, and with a single row of spines, anterior tibitc feebly 

 dentate. Epipleurai bistriate. Elytra with subhumeral stria abbreviated 

 at apex. Surface densely punctured. 



