HEMICKEPIDIUS. — ALLOTRIOPSIS. 489 



it is smaller and less elongate, and also differs from it in the more shining and less rugose 

 elytral interstices, the shorter antennas in the male, and the less produced hind angles 

 of the thorax, the latter with the black mark on the disc dilated laterally in the males, 

 so as to form a large cruciform patch (in H. cruciatus the black mark is usually 

 interrupted or constricted about the middle). In a few of the females the elytra are 

 black or piceous ; the hind angles of the thorax are sometimes obsoletely carinate at 

 the tip in this sex. From H. pictipes the present species may be known by its narrower 

 shape and more shining surface, the less densely punctured head and thorax, the latter 

 not incised on either side at the base, the much less rugose elytral interstices, &c. 

 The single specimen in the Salle collection was mixed with the series of H. longi- 

 collis, from which it differs in its smaller size, the less elongate thorax, the hind 

 angles of which are not or very indistinctly carinate and the disc is more or less 

 distinctly marked with a black cruciform patch (of which there is no trace in 

 H. longicollis), and the rather more abruptly truncate apices of the elytra. 



Group ALLOTRIINI. 

 ALLOTRIOPSIS. 



Head very deeply excavate anteriorly ; the front subtriangular, limited on either side by a sharp, oblique 

 carina, the two being coalescent in the centre, and there joining an oblique ridge extending upwards 

 from beneath the points of insertion of the antennae, the latter thus appearing to be inserted in deep 

 cavities ; eyes very large ; mandibles bifid ; antennas ( S ) exceedingly elongate, two-thirds the length of 

 body, joint 3 very short, shorter than 2, the two together not nearly so long as 4, 4-11 very elongate, 

 flattened, moderately widened, and serrate ; prothorax transverse, bisinuate at the apex and trisinuate at 

 the base, sharply margined, with long, narrow, acute hind angles ; scutellum oval, flattened, rather large ; 

 elytra very elongate, confusedly punctured, without trace of striae ; presternum moderately broad, with a 

 broad, subtruncate, prominent chin-piece, the lateral sutures single and sinuous, the process declivous 

 behind the coxae, long, and compressed ; mesosternum depressed, the borders of the cavity not raised ; 

 metasternum elongate ; posterior coxal plates rapidly narrowing from opposite the point of insertion of 

 the femora, becoming very narrow outwards ; legs elongate, rather slender ; tarsi somewhat compressed, 

 joints 2-4 slightly emarginate on the upperside at the apex, lobed beneath, the lobes becoming longer 

 and broader outwards, the lobe on the very short, penultimate joint fully two-thirds the length of the 

 apical joint and broad at the tip ; basal joint of the hind tarsi about as long as the following three joints 

 united ; claws simple. 



The remarkable Elaterid from which the above characters are taken differs from all 

 the other genera of the group Allotriini, one only of which is American, in the 

 triangular, deeply excavate front. The tarsal joints 2-4 have each a long lobe beneath, 

 as in the eastern genus Allotrius. The form of the head somewhat resembles that of 

 the genus Dicrepidius of the group Dicrepidiini, from which the present insect differs 

 in the deeply excavate triangular front, the narrow coxal plates, the strongly lobed 

 penultimate tarsal joint (this joint being simple in the Dicrepidiini), &c. The 

 form of the tarsi, &c. distinguishes it from the American genus Anaissus, Cand., 

 of the group Crepidomeni. 



biol. cente.-amer., Coleopt., Vol. III. Pt. 1, March 1896. 3 B» 



