2O4 MEMOIRS ON THE COLEOPTERA 



mesosternum. This character is certainly an important one among 

 the American members of the Asidini, though apparently of less 

 definite value among the European representatives of the tribe, 

 the importance of a character being determinable solely by its 

 constancy and consistency. With a general habitus which is suf- 

 ficiently uniform and readily recognizable, the body assumes two 

 distinct forms, the species of the first group being more ventricose 

 and larger than those of the second, glabrous in the former, sparsely 

 covered with rather long erect setae in the second; the elytra are 

 strongly margined at the sides nearly to the apical angles and quite 

 uniformly throughout the genus, but, singularly enough, the only 

 species to exhibit any sign of discal costae is the type named Pele- 

 cyphorus obsoletus, by LeConte, though just why it was placed in 

 that genus is not clearly understood, as the fourth male maxillary 

 palpal joint is sharply recti-triangular, while in the female it is 

 acute at the angle of attachment, just as in all the preceding genera 

 subsequent to Euschides in the table. The mentum is short and 

 transversely obtrapezoidal, touching the sides of the buccal opening, 

 which are moderately short, obtuse in the first group and rather 

 acute at tip in the second. The base of the prothorax is truncate 

 or broadly sinuate, the basal angles generally acute and sometimes 

 obliquely prominent, the elytral base about as wide as the thoracic 

 base and the humeral angles obtuse and usually rather blunt though 

 evident, the reflexed cariniform margin not notably more elevated 

 basally. The trochantin is well developed, the eyes, labrum and 

 epistoma as in Euschides, the anterior tibiae generally finely everted 

 and acutely aciculate externally at apex, the legs and tarsi moder- 

 ate; the antennae are rather slender, with the tenth joint somewhat 

 abruptly wider nearly as in Trichiasida. The two subgeneric 

 groups may be defined as follows: 



Body larger and rather stout, more ventricose, glabrous, the tarsi rather 

 long, having short spinuliform hairs beneath Group I 



Body smaller, sometimes very small, more parallel, the prothorax never 

 more than slightly narrower than the elytra; dorsal surface sparsely 

 clothed with erect flavo-fulvous setse; tarsi much shorter, densely 

 clothed beneath with inclined stiff pale hairs Group II 



The first of these groups occurs in Arizona and southern California, 

 but the second seems to be confined to the latter region and is more 

 maritime, being particularly abundant near San Diego. 



