AMERICAN COLEOPTERA. 43 



Tribe 1. — Chauliognathini. 

 This tribe consists of but one genus represented in our fauna by a 

 moderate number of species. They are much more numerous in Tropical 

 America, but so far as I am aware do not occur in other countries. 



CHAUI.IOGIVATHIIS Hentz. 



This genus differs from all others in our fauna not only by the 

 elongated head, and singular structure of the maxillary lobe which has 

 a long extensile and contractile fleshy filament, but also by the peculiar 

 arrangement of the under surface of the prothorax, and the sexual 

 characters of the % . 



The prosternum is but feebl} developed, and separated by membrane 

 from the surrounding parts. The trochantin is very large, triangular and 

 flat, and the inflexed flanks wide and concave ; the two gular plates at 

 the anterior margin of the prosternum are large and prominent, dipping 

 perpendicularly inwards. The mentum is very long and narrow, a little 

 broader in front ; the gailar sutures run from the hind angles of the 

 mentum obliquely inwards, and coalesce on the median line, almost to 

 the hind margin of the lower floor of the cranium. 



The last ventral segment of the % is elongate-oval, convex, and of 

 firmer corneous consistency than the other segments; the penultimate 

 ventral is emarginated broadly and deeply by the convexity of the last 

 segment ; from the terminal opening between the last ventral and dorsal 

 is frequently seen protruding a pair of claspers, of slender curved form, 

 hooked at the end and fringed on the inner margin with spines, thus 

 resembling the inner lobe of the maxillae of Carabidfe. 



These characters and those already given by me in the Classification 

 (p. 186), abundantly indicate the propriety of recognizing this type as a 

 separate tribe. 



In several species the antennae in the % are longer than in the 9 , 

 and the outer joints are somewhat broader ; but there is not sufficient 

 difference in this respect to be worth indicating among the specific 

 characters in the tahle. 

 Antennse slender in both sexes. 



Antennae with third joint equal, or nearly so, to fourth 2. 



Antennse with third joint conspicuously shorter than the fourth t 5. 



2. — Head yellow; prothorax opake 3. 



Head black; prothorax shining ■ 4. 



3._Prothorax wider than long, sides very broadly and strongly reflexed ; red, 

 finely pubescent; mouth organs, three prothoracic dots, abdominal spots 

 and last segments, legs, except at base, and posterior one-fourth to one-fifth 

 of elytra black; antennse testaceous and dusky, scape black. Length 13— 

 17 mm.: Arizona 1- prolundus. 



