224 HYMENOPTEBA. 



Metathorax with a gradual slope from the base to the apex ; the base is black, except 

 at the edge of the pleurae, and the black is continued down the centre as a black band, 

 which becomes narrower towards the apex. Abdomen shining, impunctate ; all the 

 segments broadly white at the apex, the ventral surface being also white. Legs longish, 

 slender ; the apices of the hind femora, tibiae, and tarsi, black ; the base of the tarsi 

 and the spines being also black. The mark on the mesonotum is large and broad, the 

 sutures are distinct, and the notum on either side of the black postscutellum is coloured 

 like the pleurae. 



— 26. Mesostenus chichimecus. 



Mesostenus chichimecus, Cresson, Proc. Acad. Phil. 1873, p. 155 ( $ ) \ 

 Hab. Mexico, Orizaba, Cordova l (Sumichrast). 



27. Mesostenus admirandus. 



Mesostenus admirandus, Cresson, Proc. Acad. Phil. 1873, p. 155 ( $ ) *. 

 Hab. Mexico, Orizaba x (Sumichrast). 



28. Mesostenus arcuatus. 



Mesostenus arcuatus, Cresson, Proc. Acad. Phil. 1873, p. 156 ( $ ) \ 

 Hab. Mexico, Orizaba 1 (Sumichrast). 



29. Mesostenus admotus. 



Mesostenus admotus, Cresson, Proc. Acad. Phil. 1873, p. 156 ( $ ) 1 . 

 Hab. Mexico, Orizaba x (Sumichrast). 



3. Mesothorax with two yellow lines on the disc. (Species 30 to 32.) 



30. Mesostenus megapoda. (Tab. X. fig. 19.) 



Niger, flavo-varius ; femoribus supra apiceque tibiarum posticarum, nigris ; alis hyalinis, apice fumatis. <? . 

 Long. 14 millim. ; terebra 4 millim. 



Hab. Guatemala, El Tumbador (Champion). 



Antennae stout, not much longer than the body. Head punctured, the face more 

 strongly transversely striated in the centre, the centre of the vertex aciculate ; front 

 projecting, with two black lines running down the centre to the mandibles round the 

 sides of the clypeus ; the latter is blackish round the edge ; mandibles black, yellow at the 

 base. Mesonotum aciculated, with some scattered punctures ; the pleurse striated in the 

 middle ; base of the metanotum scarcely punctured, the rest strongly striated, reticu- 

 lated below the spiracles. Tubercles longish, a mere dilatation of the carina. Scutellum 

 not much longer than broad, finely punctured, rounded at the apex. The head is 

 yellow, except the centre of the vertex and behind; the prosternum, the tegulse, and 



