326 HTMENOPTEEA. 



vertex and the upper part of the front covered with golden pubescence ; the apex of 

 the clypeus bluntly rounded, shagreened, fringed with golden hair; the mandibles 

 before the apex ferruginous. The head rounded in front, transverse behind ; the 

 hinder part hardly twice the length of the eyes ; the middle is slightly dilated and is 

 about level with the eyes ; behind it is slightly narrowed. The scape of the antennae 

 very slightly pubescent ; the flagellum more or less reddish-brown beneath ; the third 

 joint more than twice the length of the fourth. The thorax coarsely punctured ; the 

 centre with golden pubescence ; the base bluntly rounded ; the apex narrowed, trun- 

 cated, sharply obliquely sloped; at the sides the base projects into a small tooth, 

 beyond this is another small tooth, and from the middle is a shallow curve having a small 

 tooth at the base and the apex and another in the centre ; the edge of the median 

 segment with three stout teeth. The base of the propleurae obliquely cut off from the 

 apex, which is somewhat strongly punctured; the meso- and metapleurae smooth, 

 impunctate, glabrous, save a crenulated ridge on the former. The basal segment of the 

 abdomen bears white hair and is coarsely punctured ; at the base laterally are two 

 small, elongate, blood-red marks ; near the apex are two large, roundish, orange maculae. 

 The third to the fifth segments are closely, not very finely punctured, and fringed 

 lightly with silvery hair ; the pygidium at the apex is covered with stiff, long, fulvous 

 hair. The basal ventral segment can hardly be said to be keeled, it being so broad and 

 rounded ; the second segment bears large, elongated, deep punctures and a few long 

 white hairs ; the other ventral segments are punctured all over, and fringed with long, 

 pale, fulvous hair; on the sides of the third, fourth, and fifth segments is an oblique 

 furrow. The tibiae and tarsi are thickly covered with white hair ; the hair on the hind 

 legs inclines to fulvous. I can see no spines on the hinder tibiae: if they are not broken, 

 the calcaria are very short. 



S. amphissa, to which the present species bears a certain resemblance, differs from 

 S. orithyia in having the head not dilated from the posterior margin of the eyes ; the 

 pubescence on the head and mesonotum denser and white ; the base of the propleurae 

 not obliquely truncated, and cut off from the apical part; the second abdominal 

 segment with only the large maculae; and the basal ventral segment distinctly 

 keeled. 



Some examples from North Yucatan (Gaumer) are probably varieties of S. orithyia. 

 They are smaller, being only 10 millim. in length ; the incision in the centre of the 

 thorax is apparently deeper ; the two marks on the second abdominal segment are 

 longer, being longer than broad (the converse being the case with the type) ; and the 

 apical segments of the abdomen are densely covered with bright golden hair, hiding the 

 sculpture entirely. The clothing of the apical abdominal segments in the type is 

 apparently rubbed off. 



