Coleopterological Notices, V. 435 



Delenda Croiss. (^Eusonoma Reit.) has been recently proposed 

 (Coleopterologiste, 1891, p. 152) for a small species from Asia Minor. 

 It is closely related to Rafonus but appears to differ decidedly in the 

 structure of the upper surface of the head. 



SONOm A Casey. 



In this genus the head is generally small, the eyes well developed, 

 the tempora somewhat variable, generally rapidly convergent and 

 rounded to the neck, sometimes rounded and about as prominent 

 as the eye, never in the least angulate. Upper surface constantly 

 with two small nude post-median fovetfi, and a large extremely deep 

 abruptly excavated subapical pit, which is always more acutely 

 rounded behind and with its anterior margin more transverse. On 

 the under surface there is a deep transverse sulcus just behind the 

 mentum and maxillae, the plane of these parts sloping rapidly up- 

 ward from the base, the base of the maxillary cardo greatly ex- 

 posed ; there is also a deep transverse and perfectly simple nuchal 

 constriction. The under surface never has anj sign of the singular 

 and complicated excavations and caringe so common in Sagola. 



The maxillary palpi have the first joint minute, simple and 

 scarcely more than one-third as long as the second, otherwise 

 nearly as in Sagola. Antennaj submoniliform, with the joints 

 loosely connected throughout, as usual in the tribe, gradually 

 thicker toward apex and with the basal joint much thicker and 

 longer than the second. The antennae are more clavate than in 

 Sagola, but much less so and shorter than in Rafonus. The pro- 

 notum has constantly two small discal fovese at the middle, besides 

 the complex subbasal impressions, and the metasternum a long 

 broad deep canal extending posteriorly from the outer side of the 

 middle acetabula. 



The remarkable asymmetric modifications of the sixth ventral 

 segment of the female and the ventral pygidium of the male have 

 been alluded to above. They are present in both of our genera, 

 and probably constitute one of the most characteristic distinguish- 

 ing features of the tribe. The asymmetry affects very different 

 forms in the various species of the same genus, as may be seen 

 from the few examples figured on the plate.' 



^ Tlie staphylinide genus Palamhius is also remarkable in having asym- 

 metric male sexual characters at the ventral apex. 



