Species of Formicarious Histeridge. 145 



Pachycroirus is known from Platysoma hj the apex of the 

 mesosternum being produced and bj its entering the region of 

 the prosternum, which is proportionally incised to receive it ; 

 and as we go further down in the catalogue of genera the 

 structure of the sterna receives fuller recognition. And 

 bejond this several describers of species, myself included, 

 have not always been careful in examining and recording the 

 characters which exist in a prominent degree on the under 

 surface of some species when the superstructure fails to 

 suggest details for a satisfactory diagnosis. 



The undereides of the Histerida3 are of the utmost import- 

 ance in classification and intensely interesting as a study of 

 structure. I do not anticipate the discovery of many new 

 species in the genus Satrapes, but in Hetcerius and Sternoccelis 

 the next few years are certain to bring many to us, as ento- 

 mologists are becoming alive to the fact that numbers exist, 

 and that the species, if properly sought for, are not difficult to 

 find. I have taken eleven species myself this year. 



Hetcerius grains^ Lewis. 



This species is very similar to ferrugineus above and below, 

 but the prosternal stria3 meet each other more acutely in front, 

 and being less sinuate are not at anyplace so widely separated 

 as in Olivier's species. 



Hetcerius hrunneipennis^ Rand. 



The sterna here also correspond very closely with those of 

 ferrugineus, but the prosternal lines are not sinuate at the 

 coxK, and, being straighter laterally, they enclose a space 

 which resembles an elongate triangle. 



Hetmrius jplicicollis, Fairm. 



The substructure of this insect is peculiar in the widening 

 out, on the same plane as the base, of the anterior lobe of the 

 prosternum, and the limit of the lobe is indicated by a mar- 

 ginal line. The stria; at the base of the prosternum are con- 

 lined to the region of the coxee, and the lateral excavations of 

 the mesosternum are small and relatively shallow. 



Hetcerius optatus, Lewis. 



The prosternum is broad an.d densely opaque, with large 

 Ann. & Mag. N. Hist. Ser. 6. Vol. ii. 10 



