Goleopterological Notices, V. 523 



compressum diifers from gammaroides in the narrower and more 

 parallel met-episterna. Length 1. 4-1.1 mm.; width 0.7-0.8 mm. 



Kansas and Nebraska to Florida. I can distinguish no distinct 

 trace of mes-epimera in either of these species. 



SCAPHISOMA Leach. 



The species of Scaphisoma exceed in number those of Baeocera, 

 but are less readily difl'erentiable. The antennae are generally 

 longer and have the outer joints more bilaterally asymmetric as a 

 rule, the third joint always very small, seldom more than one-half 

 as long as the fourth, enlarged and more or less oblique at apex 

 and constricted at base. There are two tolerably well-defined 

 types of antennal structure, one having the sixth joint rather 

 shorter than the fifth, the other with this joint greatly elongate, 

 sometimes equalling the preceding three together. In the latter 

 type the sixth joint is somewhat dilated with^in and bristling with 

 erect setae like those beyond it ; in fact in the first type, the club — 

 if the loose chain of peculiar flattened internally arcuate joints can 

 be thus designated — begins with the seventh joint, and in the 

 second with the sixth. I have made no use of these types of 

 structure in classifying the species, as the character relating to 

 the mes-epimera seems to be more important and less subject to 

 sexual modification. The scutellum is present in all of our spe- 

 cies, though very small and sometimes extremely minute ; it is 

 invariably equilateral or nearly so. The basal stria of the elytra 

 is never entire, as it frequently is in Baeocera. 



The following table may enable the reader to identify the forms 

 in his cabinet, although there are probably a considerable number 

 still to be discovered : — 



Mes-epimera extending one-lialf or more to the coxae, always distinctly defined. 

 Metasternum strongly though sparsely punctate throughout, the punctures 



extending also to the outer parts of the episterna repailda, 



Metasternum subimpunctate or only punctured in part. 

 Body black, sometimes castaneous from immaturity. 

 Larger species, never much under 2 mm. in length. 

 Elytra sparsely but strongly punctate. 



Metasternum, between the middle and hind coxae, coarsely and 



strongly punctate -.COllTCXa 



Metasternum minutely and remotely punctate ; elytral punctures 



stronger; form a little more elongate-oval castanea. 



Elytra finely but much more closely punctate, the punctures almost 

 twice as numerous as in concexa puiictulata 



