NORTH AMERICAN COLEOPTERA. 251 



stantly, a coarse puncture near the basal edge of the thorax on each 

 side of middle. While in Philydrus four irregular series of coarse 

 punctures are observed on the elytra, here we have but two placed 

 on the fifth and ninth intervals. 



The presence of a well marked mesosternal lamina in most Philyd- 

 rus and its absence in Helochares seems not to be a character of any 

 great importance as one species of the former (ochraceus) has merely 

 a mesosternal carina, which is nearly as well marked in one of the 

 Helochares {normatus). 



The two species known to me are separable as follows : 



Mesosternum without trace of carina; mentuiu entire in front. 



inaciilieollis. 

 Mesosternum feebly carinate; mentum slightly emarginate normatus. 



The first of these species belongs to the Atlantic region, the other 

 to the Pacific. 



H. maculicollis Muls. — Oblong oval, very obviously narrowed in front, 

 subdepressed, moderately shining; color above luteous or piceo-testaceous, thorax 

 with a rather large piceous spot, head with irregular piceous spaces. Thorax 

 closely punctate, punctures coarser toward the sides, the anterior arcuate row of 

 punctures very evident, the transverse series indistinct, basal marginal line ab- 

 sent. Elytra broadest slightly behind the middle ; the surface with ten moder- 

 ately deeply impressed stripe, which are rather finely serrately punctured, the 

 strife ending abruptly a short distance in front of the apical margin, the tenth 

 stria distant from the side, scutellar stria short; intervals flat, finely sparsely 

 punctulate, the fifth and ninth intervals with a row of coarser punctures. Body 

 beneath black, feebly shining. Femora piceous, opaque, tibife and tarsi rufo- 

 piceous. Length .16 — .22 inch.; 4 — 5.5 mm. 



The prosternum is carinate, but never very distinctly. The mesosternum has 

 a slight tuberosity at middle, somewhat rugose. The claws are similar on all 

 the feet and alike in the sexes, they are feebly curved, slightly dilated at base, 

 but not toothed. In specimens which I suppose to be males the last ventral seg- 

 ment has a slight emargination at the middle of its apex. 



Variations have been observed in color and sculpture. In what 

 seem to be fresh and well-preserved specimens the color is luteous, 

 with the usual piceous spot on the thorax, but from this the color 

 becomes gradually darker, seemingly to piceous. The head may be 

 entirely piceous with a pale space in front of the eye, or the occiput 

 only may be dark. In one specimen the entire head is simply mar- 

 gined with piceous. 



While the sculpture of the thorax is usually well marked, the 

 punctures close, specimens are seen with fine punctures more widely 

 spaced. The variation in color of head and thoracic sculpture are 

 entirely independent of sex. 



