CETONIIN^E 365 



Trinodia n. gen. 



The longitudinal division of the pronotum into three lobes by 

 deep impressions of the surface, is a character the generic sig- 

 nificance of which admits of scarcely any doubt; this, and the 

 unusually parallel form of the body, gives to Cremastocheilus 

 saucius Lee., and a number of allied species, a general habitus 

 conspicuously distinguishing them from Cremastocheilus, as repre- 

 sented by the numerous foregoing species. This trilobate external 

 feature must inevitably signify an arrangement of the internal 

 organs of the prothorax correspondingly aberrant when compared 

 with Cremastocheilus. The species are rather numerous, though less 

 so than in the preceding genus, and those already discovered are 

 assignable to two well marked subgeneric groups as follows: 



Pronotal impressions continuing from base to apex; hind angles deeply 

 emarginate externally, the apical angles very aberrant in structure, 

 having an external cavity delimiting a sometimes retracted slender 

 oblique lobe; clypeus not dilated at the sides and having a very high 

 and conspicuous median carina, longitudinally crossing the concavity; 

 anterior tibiae slender, the two teeth widely separated. . . .Group I 



Pronotal impressions extending from base to scarcely beyond the middle, 

 the basal angles broad, convex, separated from the base by the usual 

 deep sinus and not modified externally, the apical angles as in 

 Cremastocheilus but projecting anteriorly and not inwardly oblique; 

 clypeus strongly dilated laterally, not carinate; anterior tibiae as in 

 Cremastocheiles, broad, the two teeth much more approximate as 

 usual in that genus Group II 



The mentum in the first group, or Trinodia proper, is deeply 

 concave to flat, in the latter case with reflexed hind margins; 

 this is a conspicuous difference and is almost undoubtedly of a 

 sexual nature; the plate is more or less sinuate at each side and, 

 at the hind margin, it is entire, sometimes slightly produced medi- 

 ally. In the second group, now represented by Cremastocheilus 

 wheeleri alone, the mentum is very different; it is more transverse, 

 deeply concave, having each side prolonged and lobiform and the 

 hind margin is broadly bisinuate and transverse, a form of mentum 



day, flying rarely over the sand dunes, but more commonly found early in the morn- 

 ing buried in the sand under sticks or other objects. They are not difficult to capture 

 in the cooler part of the day, but during the warmer parts they must be picked up 

 quickly when they alight on the sand, or a net thrown over them, as they sit quietly 

 only a short time after alighting before they again take flight." (Bull. Bk. Ent. Soc., 

 X. p. 39-) 



