292 SEEEICOENIA. 



A widely distributed insect in Tropical America. I have seen altogether twenty-nine 

 specimens of 8. ligneus, the whole of which are females. In this sex the fifth ventral 

 segment has two very large, rounded, piliferous fovese beyond the middle, the apex of 

 the segment being almost rounded. Nine examples from Central America are before 

 me, five of these being from Chontales. 



The published figures of this species are rather unsatisfactory ; we therefore give a 

 fresh one, taken from a Chontales specimen. 



OISTUS. 

 Oistus, Candeze, Monogr. Elat. i. p. 338 (1857). 



This genus, the American exponent of the eastern Campsostemus, contains two 

 species only, both peculiar to Central America, one of them extending as far south 

 as Nicaragua. 



In this genus, again, the males are much rarer than the females ; they may be 

 distinguished by the form of the fifth ventral segment. 



Eyes very large ; prothorax with a smooth bare spot on either side of the disc a 

 little before the middle ; elytra with smooth bare spots, the vestiture forming 

 distinct fascicles cacicus. 



Eyes small ; prothorax without smooth bare spots on the disc ; elytral vestiture 



not forming distinct fascicles, the bare spots not distinctly defined .... sphenosomus. 



1. Oistus CaciCTlS. (Tab. XIII. figg. 8 ; 8 a, fifth ventral segment, <j .) 

 Oistus cacicus, Cand. Monogr. Elat. i. p. 339, t. 6. figg. 5, 5 a-c x ; Revis. Elat. p. 189 2 . 



Hah. Mexico, Orizaba 1 2 , Tuxtla, Santecomapan (Salle), Jalapa, Las Vigas (H'dge) ; 

 Guatemala, Coban (Conradt); Nicakagua, Chontales (Belt). 



Nine specimens of this species are before me, one of which is a male. It has the 

 apex of the fifth ventral segment produced in the middle into a long process, 

 which is rounded at the tip and curved upwards. On the elytra there are numerous 

 bare smooth spots, the interspaces between which are here and there densely, very 

 minutely punctate, and clothed with hair-like scales, these forming fascicles on the 

 densely punctured places. We figure a male from Coban. 



2. Oistus Sphenosomus. (Tab. XIII. figg. 7; 7 a, fifth ventral segment, 6 .) 

 Oistus sphenosomus, Cand. Monogr. Elat. i. p. 339 '; Eevis. Elat. p. 189 2 . 



Hob. Mexico, Orizaba 1 2 (Salle), Jalapa (Salle, H'dge), Las Vigas (H'dge). 



Not uncommon in the State of Vera Cruz. Much smaller than the preceding, the 

 eyes smaller, the thorax without a smooth bare spot on either side of the disc, the 

 hair-like scales on the elytra not forming distinct fascicles. The type described by 



