Coleopterological Notices, IV. C21 



large, vertical, strongly convex and completely exposed, while in 

 the female it is entirely covered, with the exception of a very small 

 and barely distinguishaljle portion at the apex. In other words, 

 assuming the division adopted by LeConte, which is still, without 

 much doubt, the best that can be devised, the male is a normal 

 baride, while the female is an equally pronounced centrin'ide. This 

 of course destroys any idea of two perfectly isolated natural groups, 

 and compels us to treat the genera as forming part of a single well- 

 defined series. In fact the homogeneity of the entire tribe is proved 

 by repeated parallelisms of structure throughout. 



In Centrinogyna the body is elongate, parallel and somewhat 

 depressed, nearly as in aiany species of Limnobaris. The beak is 

 rather slender, arcuate, about as long as the prothorax, with the 

 antennae inserted distinctly beyond the middle, slender, moderate 

 in length, the first funicular joint as long as the next four, the 

 second slightly elongate but less than one-half as long as the first, 

 the club oval, abrupt, densely pubescent and with the basal joint 

 constituting ver}" nearly one-half of the mass. Mandibles deeply 

 notched within, acute, not noticeably overlapping when closed and 

 then formiug a prominent angle. 



The prosternum is perfectly unimpressed, having the usual deep 

 transverse constriction behind the apex but not otherwise modified, 

 the anterior coxa? not very widely distant and separated by but 

 slightly more than one-half of their own width, the prosternal pro- 

 cess terminating midway of their length in a distinct transverse 

 suture ; behind this, the prosternum is but slightly produced, pass- 

 ing for only a short distance over the edge of the mesosternum, 

 with the apex broadly and feebly sinuate in "the middle. The pro- 

 thorax is strongly tubulate at apex. Scutellum very small, sub- 

 quadrate or a little longer than wide. Legs normal ; tibiae nearly 

 smooth, the tarsal claws well developed, stout, free and divergent. 

 Yestiture throughout consisting of very sparse slender setiform 

 squamules, white in color and arranged in a single somewhat 

 uneven semi-erect and bristling line on each of the elytral intervals. 



This genus offers a good example of the polarity theory in the dis- 

 tribution of secondary sexual characters, advanced by Dr. LeConte, 

 the beak and antennae being quite devoid of any perceptible sexual 

 diflerences, while those at the apex of the abdomen are exception- 

 ally pronounced. The theory does HOt hold so well, however, in 

 some other genera, as for example in several species of Oxytelus 



