4 GEO. H. HORN, M. D. 



tibiae fimbriate with short equal spinules ; first joint of hind tarsus a 

 little longer than the three following. Front tuberculate in both sexes. 

 One species forms this group. 



A. fV>ssor Linu. — Obloug, very convex, black, shining. Head sparsely punc- 

 tate, clypeus broadly feebly emarginate, genfe prominent, but obtuse. Antennae 

 ferruginous, club piceous, palpi piceous. Thorax convex, smooth, a few coarse 

 punctures toward the sides and near the front angles ; sides arcuate, sinuate in 

 front of the hind angles, base subtruncate, a deeply impressed marginal line. 

 Elytra strongly convex, a little longer than wide, striate, striae moderately closely 

 punctured, intervals slightly convex, smooth. Mesosteruum not carinate. Met- 

 asternum moderately closely punctate at the sides, abdomen obsoletely punctate. 

 Posterior femora sparsely punctate and with an irregular row of coarse punc- 

 tures. Length .40-. 44 inch ; 10-11 mm. 



Male. — Head trituberculate, the middle tubercle more ])rominent. Thorax 

 with a slight depression in front. Anterior tibial spur stout, broader to tip and 

 obtuse. Metasternum deeply impressed. 



Female. — Head feebly trituberculate. Thorax not impressed in front. Ante- 

 rior tibial spur more slender toward the tip and acute. Metasternum less concave. 



A variety (sijlvatlcus) occurs in Europe in which the elytra are red. 



This species has been introduced from Euroj^e into the New Eng- 

 land States and Canada, but seems not to have become very abun- 

 dant. 



Subgeu. DiAPTERNA Horn. 



Scutellum large, more than a fourth the length of the suture. An- 

 terior tibiae normally tridentate, not serrulate above, the anterior face 

 smooth ; first joint of the tarsus shorter than the second. Posterior 

 tibiae fimbriate at apex with unequal spinules ; the first joint of the 

 tarsus nearly as long as the next three. Front not tuberculate in 

 either sex. 



The characters of this grouj) are as well marked as those to which 

 generic names have been given in the Mulsant system of division. 

 It seems to be peculiar to our fauna. 



Since my previous study of the species of this group ( Trans. Am. 

 Ent. Soc. 1870, p. Ill) Baron Harold has received sufficient material 

 to warrant the expression of opinion that the six species there indi- 

 cated constitute but one. In a letter to him anterior to his publica- 

 tion (Berl. Zeitschr. 1874, p. 182) I assented to his view, except as 

 to occidentalis. A further study, however, has modified my opinion, 

 which may be expressed in the following table : 



Thorax wider in front and broader than the elytra; first joint of posterior tarsus 

 % longer than the next three joints, the hook large validus. 



Thorax not wider in front and not wider than the elytra; first joint of hind 

 tarsus % shorter than the next three, the hook rather feeble.. ..liaiuaf us. 



