GASTKAULACUS.— IDIOTARSUS. 215 



GASTRAULACUS. 



Gastraulacus, Guerin, Ann. Soc. Ent. Fr. 1843, p. 188; de Bonvouloir, Mon. des Eucnemides, 

 p. 112. 



This genus is remarkable in that the middle and posterior tarsi are received in deep 

 grooves in the metasternum and abdomen respectively. But one species has hitherto 

 been known, to which another is now added. 



1. Gastraulacus bisulcatus. 



Galba bisulcatus (sic), Latr. Ann. Soc. Ent. Fr. 1834, p. 132 \ 



Gastraulacus bisulcatus, de Bonv. Mon. p. 113. t. 5. fig. 4 2 . , $3r>- 



Gastraulacus atratus, Guerin, Ann. Soc. Ent. Fr. 1843, p. 188, t. 6. figs. 50, 51 3 . - ovP- •"jm-wy 



Hah. Mexico 23 ; Nicaeagua (Salle), Chontales (Belt).— Colombia 3 ; Brazil 12 . 



2. Gastraulacus cavifrons. (Tab. x. fig. 9.) 



Cylindrical, slightly narrowed posteriorly, robust, brownish-piceous, subopaque ; antennae ferruginous, basal 

 joint piceous : bead coarsely closely punctate, deeply impressed from the occiput to the base of the clypeus ; 

 thorax nearly one half wider than long, sides parallel posteriorly, arcuately narrowed in front, disc convex, 

 median line impressed from a point in front of the base to three fourths of the distance to the apex, the 

 impression sharp posteriorly, broader in front, surface rather roughly granulate, with a tendency to form 

 rugae, coarsely punctate at the hind angles ; elytra vaguely striate, striae indistinctly punctate, intervals 

 slightly convex, coarsely transversely wrinkled, the juxta-sutural region elevated near the apex ; body 

 beneath coarsely, not closely punctate, metasternum and the sides of the abdomen smoother ; legs rufo- 

 piceous. 



Length 13-5 millim. 



Hob. Nicaragua, Chontales (Belt). 



Larger and more robust than the preceding species, from which it differs notably in 

 having the metasternal sulci very oblique, extending in an almost direct line from the 

 outer front angles of the metasternum to near the middle of the posterior margin. In 

 G. bisulcatus these sulci are for a distance parallel with the episternal suture. The 

 ventral sulci also converge slightly and are extended in a well-defined manner on the 

 last segment. 



IDIOTARSUS. 



Idiotarsus, de Bonvouloir, Mon. des Eucnemides, p. 137 (1870). 



This genus is readily known from any other at present represented in our fauna by 

 the presence of the straight metasternal grooves without ventral grooves. Until the 

 discovery of the present species the genus has been restricted to South America. 



l. Idiotarsus estriatus. 



Oblong, subcylindrical, narrowed posteriorly, piceous, shining, sparsely clothed with brownish-yellow pubescence, 

 which tends to arrange itself in rows near the apex of the elytra : margin of the clypeus bisinuate, the 

 lateral margins slightly elevated ; head moderately closely punctate, median carina well marked, extending 



