NORTH OF MEXICO. 259 



nent middle lobe of the epistoma. This lobe is rounded in front, more acute at its mid- 

 dle, emarginate at the sides, and with a very convex surface, so that the front is umbonate. 

 The labrum is not visible. The maxillary palpi have nearly equal joints, the last being 

 feebly triangular. They are alike in both sexes. The metasternal parapleural are nar- 

 row, the elytral epipleurse narrow, but separated by a distinct line. 

 The species of this genus may be tabulated — 

 Head smooth, thorax transverse, frontal umbone large. nodiceps. 



Head coarsely punctured, thorax transverse, frontal umbone moderate, p u n c t a t u s . 

 Head punctured or sulcate, thorax quadrate, narrower behind. 



Elytra shining. 1 se vi s . 



Elytra opaque, pubescent. subpubescens. 



T. nodiceps, Lee, Proc. Acad. 6, 447; Thomson, Arcana, Vol. I, PI. XIII, fig. T. 



This is our largest species, and may be distinguished by the almost entirely smooth 

 head, the transverse and finely and densely punctured thorax. The frontal umbone is 

 more convex than in any of our other species. Found in Texas. 



Length .30 inch. 



T. punetatus, Lee, Ann. Lye. 5, 140. 



But one specimen of this species is known, a single dead individual having been 

 found at Vallecito, C'al. It is stouter and more robust than the other species. The head 

 is coarsely punctured, and the thorax transverse coarsely and confluently punctured. 



Length .25 inch. 



T. lsevis, Lee, Ann. Lye. 5, 141; rugiceps, Lee, loe cit.; Lao. Genera, pi. 48, fig. 4. 



This is the most abundant of our species. Specimens occur from Tejon, C'al., to the 

 western base of the Rocky Mountains in Arizona. The thorax is nearly as long as broad 

 and notably narrower behind, and has its upper surface finely but distantly punctured. 

 The head varies in sculpture ; in some the punctures are very fine and distant, in others 

 the head is sulcate by the confluence of coarse punctures. These two forms constitute re- 

 spectively Icevis and rugiceps. I have had opportunity of examining many specimens, and 

 find every shade of variation from one to the other. 



Length .25 inch. 



T. subpubescens, brownish black, sub-opaque. Head coarsely and densely punctured and longitudinally finely 

 sulcate; umbone moderately prominent, finely punctured. Thorax slightly broader than long, sides moderately 

 rounded. Surface convex, coarsely and densely but not confluently punctured. Head and thorax with sparsely 

 placed short yellow hairs. Elytra oval, moderately convex, faintly striato-punctate with the interstices with two rows 

 of very faint punctures, sparsely pubescent with the short hairs arranged between the rows of larger punctures. Body 

 beneath paler. Thorax coarsely and densely punctured, meso and metasterna very coarsely punctured, abdomen finely 

 and sparsely punctured. Length .30 inch. 



