EX^STHETUS.— THKOSCIM:. 193 



second segments united into one; the intercoxal process acuminate. Legs rather slender; the tibiae 

 straight ; the tarsi moderately long, the second and third joints with a very small lamina, which is 

 scarcely distinguishable when dry, the fourth joint with a rather large delicate lamina; the claws dilated 

 at their basal half (figg. 15 d, e). 



I think this very aberrant Buprestid may be placed next to Mastogenius. Its general 

 appearance is suggestive of Haplocnemus in the Dasytidae. 



1. Exsesthetus dasytoides. (Tab. IX. figg. 15, 15 a-e.) 



Elongatus, paullo convexus, nitidus, subtus fere niger, supra nigrescenti-ameus ; capite leviter convexo, sat 

 crebre subtiliter punctato ; thorace antice angustato, convexo, sat crebre evidenter punctato, lateribus sat 

 rotundatis ; elytris sat crebre fortiter punctatis. 



Long. 2 lin. 



Hab. Mexico, Jalapa [Edge). 



The head has an impression in the middle of the lower part of the face. The thorax 

 is impressed at the base, convex on the disc; the punctures are very distinct, rather 

 close together. The elytra have the punctures rather strong and moderately close 

 together. 



Fam. THKOSCID^G*. 



This family is composed of a small number of genera and species, not very closely 

 related among themselves, occupying a position in the coleopterous series intermediate 

 between the Buprestidse and Eucnemidse, and no definition has yet been given which 

 will, with certainty, separate the Throscidse, as at present constituted, from those 

 between which it is placed. As the family is generally admitted, and as there is accord 

 as to its constituent genera, these will be discussed in their relation to each other. 



The genera divide into three series : — 



Antennas strongly serrate or subpectinate from the 



fourth to the tenth joints Lissomus, Hypoch^tes, Drapetes. 



Antennas terminated by a loose three-jointed club . Throscus, Aulonothroscus. 



Antennas fusiform Pactopus. 



Before entering further on this subject, it may be well to state that Lissomus has 

 been placed at the head of the series as the more nearly related to the Buprestidse as 

 Throscus and Aulonothroscus are evidently to the Eucnemidse. 



The details of these genera have been given at such length that but little is required 

 at present beyond an examination of the metasternum. 



In Lissomus there will be observed beginning at the inner side of the middle coxal 

 cavity a finely elevated line which curves slightly backward and outward, and gradually 

 disappears. In L.flavipennis this line makes almost a semicircular curve. 



Hyvochcetes has a short postcoxal line as in Lissomus. From an examination of a 



* By G. H. Hokbt. 

 biol. CENTE.-AMER., Coleopt., Vol. III. Pt. 1, November 1890. 2 



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