88 MEMOIRS ON THE COLEOPTERA 



fourth joint there is sometimes a feeble swelling, giving the appear- 

 ance of a nodiform joint, such as is well developed in Coccinellidae 

 and in many other sections of the Coleoptera, but there is never 

 any obvious suture separating it from the remainder of the joint; 

 this was probably the case, however, at some previous epoch in the 

 development of the stem forms, possibly not so very remote in 

 point of time. 



The males may be known very readily by the small terminal 

 segment behind the long and gently sloping pygidium and wholly 

 wanting in the female, but there is elsewhere but little sexual 

 difference, except in Europs and a few other genera, where the size 

 of the head is very much greater in the male than in the female 

 of some species. 



Monotoma Hbst. 



The species of this genus are very coarsely and roughly sculptured 

 as a rule and are much more numerous in temperate than tropical 

 latitudes of North America, being largely replaced in the latter 

 regions by Europs and Bactridium, or genera allied to the latter, 

 which are feebly sculptured. Of the more widely disseminated or 

 cosmopolitan species of Monotoma, there are at hand picipes Hbst., 

 from New York, Indiana, Nebraska, Esmeralda Co., Nevada and 

 southern California; americana Aube, from Illinois to Florida and 

 Texas, most abundant in the last named region, and the very 

 isolated and more feebly sculptured longicollis Gyll., from District 

 of Columbia, New York and in considerable series from Esmeralda 

 Co., Nevada. The following species are believed to be undescribed 

 hitherto: 



Monotoma obsolescens n. sp. Form rather slender, feebly ventricu- 

 late and moderately small 'in size, piceous-black, the elytra feebly rufes- 

 cent, the antennae and legs bright testaceous; head evidently narrower 

 than the prothorax, deeply biimpressed and coarsely and closely, rugosely 

 punctate; antennae unusually short, excepting the club they are equal in 

 length to the head, the third joint barely more than one-half longer than 

 wide; prothorax not quite as wide as long, the apex barely visibly nar- 

 rower than the base, the sides very feebly serrulate and nearly straight, 

 all the angles minutely, prominently and subequally nodiform; surface 

 convex, very coarsely punctured, the punctures polygonally crowded 

 laterally but separated by half to three-fourths their diameters dorsally, 

 the subbasal impressions barely traceable; scutellum small, not quite as 

 wide as long; elytra scarcely three-fifths longer than wide, two-thirds 



