222 HYMENOPTEBA. 



a L I C %' )-*- 



finely punctured ; the^parlt In front of it rugose; the apex and sides strongly striated 

 and punctured ; tubercles large, flat, transverse, hollowed in front ; the lower transverse 

 keel produced as a triangle in the centre. Petiole longish, not clearly defined from 

 the postpetiole ; black, a longish yellow line down its centre ; the apex of the postpetiole 

 and of all the other segments yellow, as are also the sides and ventral surface ; the 

 petiole is shining and impunctate, the other segments opaque, finely aciculate. Legs 

 longish, the tarsi inclining to yellow. Areolet square, open at the apex, the recurrent 

 nervure received in the middle. 



M. communis agrees very closely in coloration with the present species, but differs in 

 having a " furcate mark on the disc of the mesothorax," and the trochanters black at 

 the base ; there is no mark below the antennae, and only one oblique mark on the pleura, 

 and the petiole is entirely black. 



What I take to be the male of M. omatifrons (from Irazu) has the face entirely white, 

 the apex of the hind tibiae black, and the tarsi white, but otherwise coloured like the 

 female. The mark on the mesonotum is a little longer than broad, with the sides 

 rounded. The male of M. communis differs from this in having no tubercles on the 

 metathorax, while in the Costa-Bican specimen they are nearly as distinct as in the 

 female. It is quite possible that the latter may have a white mark on the mesonotum, 

 it being perhaps hidden by the pin. 



23. Mesostenus striatifrons. 



Niger, flavo-pictus ; macula mesonoti, scutello, postscutello, sterno, maculis pleuralibus, maculis 2 metanoti abdo- 

 minisque segmentis basalibus, flavo-testaceis ; pedibus flavo-fulvis, coxis, trochanteribus et femoribus 

 posticis, nigro-lineatis ; alis flavo-hyalinis, stigmate nigro. § . 



Long. 14 millim. ; terebra 6 millim. 



Edb. Beitish Hokdueas (Blcmcaneaux). 



Antennae stout, black, joints 8-15 clear white ; nearly as long as the body, covered 

 with microscopic pile. Head black ; the orbits (except narrowly behind), the face, 

 labrum, clypeus, and the base of the mandibles, yellowish-testaceous. Vertex lono-i- 

 tudinally striated, the hollow above the antennae shining, impunctate ; face punctured 

 covered with white hair. Thorax strongly punctured, pleurae (except a shining, im- 

 punctate space in the centre of the mesopleura) longitudinally striated ; scutellum 

 but very slightly punctured ; the base of the metanotum strongly punctured and reticu- 

 lated, the remainder transversely punctured. The prosternum, a line on the pronotum 

 the apex of the middle lobe of the mesonotum, the scutellum (except at the extreme 

 base), the scutellar keels, the sutures, the sternum, a large oblique mark on the meso- 

 pleura (united posteriorly to the yellow breast), a triangular mark under the hind wings 

 a large mark on the metapleura, two elongated marks on the metanotum covering the 

 spines and converging at the top, and the tegulae and tubercles beneath them, yellowish- 

 testaceous. Upper transverse keel on the metanotum distinct, bent upwards in the 



