EROTYLID^; 167 



but it differs in not having the head and pro thorax black, though 

 darker than in the calif ornica section, in its pallid and not black 

 scutellum, and, so far as can be inferred from the descriptions of 

 LeConte and Crotch, in its pale elytral apex and smaller size of the 

 body. The thickening of the anterior thoracic angles on the dorsal 

 surface is much more conspicuous than in any other species, and the 

 included fovea is larger. 



The following is a conspicuous species to be placed near frontalis 

 Horn: 



Triplax occipitalis n. sp. Body very elongate and parallel, the sides 

 scarcely arcuate, shining as usual; coloration exactly as in thoracica 

 throughout, except that the head is black, rufous only at base above and 

 beneath, large, more than two-thirds as wide as the prothorax, the sides 

 along the eyes and epistoma finely carinulate, the punctures not very 

 coarse but deep, sparse and irregularly distributed; eyes rather large, 

 prominent; antennae black, extending behind the prothorax, having a 

 purely 3-jointed club, the elongate eighth joint a little shorter but scarcely 

 at all thicker than the seventh; prothorax only one-half wider than long, 

 almost perfectly parallel throughout and with very feebly, evenly arcuate 

 sides, the apical angles obtuse and but slightly advanced; base broadly 

 and arcuately lobed medially, the lobe alone margined; punctures fine 

 and everywhere sparse, though more remote medially; basal margin with 

 a series of coarse punctures laterally; scutellum barely less than black; 

 elytra slightly wider than the prothorax and scarcely three times as long, 

 the series of moderate and well separated punctures not at all impressed, 

 the three outer series abruptly ending behind the pronounced numeral 

 prominences; intervals with minute sparse punctulation; under surface 

 strongly and closely punctate, the abdomen finely and densely, the apices 

 of the segments smooth. Length 5.25 mm.; width 2.25 mm. Michigan 

 (Marquette), Sherman. 



The peculiar subquadrate prothorax, large and almost entirely 

 black head and fine dense abdominal punctures, are features dis- 

 tinguishing this species at once from frontalis, where, also, the scu- 

 tellum is rufous. The last joint of the maxillary palpi is extremely 

 dilated, being four or five times as wide as long. 



In all the species of the thoracica type, and also in californica, the 

 seven shadowy spots on the pronotum are distinctly evident as a 

 rule. 



Haematochiton Gorh. 



The following, from the mountains of southern Arizona, resembles 

 very closely to superficial view, the Durango type species named 

 elateroides by Gorham, but there are some points of divergence as 

 will appear: 



