122 HYMENOPTEEA. 



part broader than long. Third antennal joint more than one-half longer than the 

 fourth, and nearly as long as the first. Thorax strongly punctured; the propleurse 

 rugosely punctured ; mesopleural furrow indistinct ; the heart-shaped area aciculate, 

 the central furrow crenulated ; the median segment with a semiabrupt rounded slope. 

 Abdomen hardly longer than the head and thorax united, rugosely punctured; the 

 petiole bulging out roundly. Pygidial area elongated, narrow, bulging out from the 

 base to near the middle, then narrowing to the apex, which is rounded, and about half 

 the width of the base ; the surface coarsely aciculate, the base rugose, with a few large 

 punctures. The incision in the hypopygium not reaching near to the middle, wide, 

 longer than broad, rounded at the base. The base of the mandibles, the inner orbits 

 of the eyes, a mark on the clypeus, an interrupted line on the pronotum, an irregular 

 mark below the tegulee, a mark on either side of the scutellum, the metanotum, two 

 large marks on the median segments, a broad band on the petiole, a narrower band on 

 the second segment, a still narrower one on the fourth segment, yellow. On the 

 mesopleurse is a stout yellow projecting spine. Anterior and intermediate femora at 

 the apex and the tibige and tarsi in front obscure yellowish- white. 



The male has the clypeus convex, the middle projecting, truncated ; the pygidial 

 area aciculate, the basal half with large punctures, the apex rounded, a little narrower 

 than the base, the sides with a distinctly raised border ; and the hypopygium keeled 

 in the middle. The clypeus is entirely black ; the lateral plates yellow. Otherwise 

 coloured as in the female. 



In having the mesopleurae spined, C. truncata agrees with C. semipetiolata ; but the 

 front spine is much longer and straighter, the clypeus is not toothed at the apex, and 

 the colour is different, the median segment being marked with yellow. 



e. Clypeus (?) completely free, projecting, truncated, or transverse at the apex. 



v 24. Cerceris imperialis. (Tab. VII. figg. 21, $ ; 21 a, clypeus, 21 b, pygidium, 

 21 c, hypopygium, $ ; 21 d, apex of clypeus, 21 e, hypopygium, 21 f, pygidium, $ , var.) 

 Cerceris imperialis, Saussure, Reise d. Novara, Hymen, p. 98, t. 4. fig. 56 \ 



Hab. Mexico, Acapulco in Guerrero {H. H. Smith), Eastern Cordillera 1 . 

 We give a renewed description from Mr. Smith's specimens : — 



Clypei pars media late libera, margine apicali late emarginato, fere dentato ; oculorum margines paralleli ; area 

 cordiformis nitida, laevis ; nigra, clypeo, oculorum marginibus, scutello maculis duabus, metanoto, maculis 

 duabus segmento mediali, abdominisque segmentis margine apicali, flavis. 



Long. 16 millim. 



Eyes slightly diverging beneath. Posterior ocelli separated from the eyes by more 

 than the length of the second and third antennal joints united, and by the length of 

 the fourth from each other. Clypeus porrect, slightly broader than long, the apex 

 with a wide rounded emargination. Antennal tubercle broadly compressed, the top 



