NORTH AMERICAN HYMENOPTERA. 243 



" Of moderate size, two and two-thirds lines. Habitat — New York. A single 

 specimen. Almost the size of Chrysis nitidula % , the body of moderate size as to 

 thickness, above green-bhie, the head in front, pectus, and feet green, the venter 

 strongly vaulted, for the most part concolorous: tarsi fuscous; head and thorax 

 closely but moderately punctured ; facial cavity of the head rectangular, punc- 

 tured, eariaceous, of moderate size, margined above, transverse margin unequal, 

 subarcuate; antennae of moderate size, fuscous, green at the base; clypeus short, 

 transverse, punctured, convex on the disc, slightly arcuate; emarginate at the 

 centre of the apical margin ; mandibles piceous, greenish at the base ; thorax 

 thick, subquadrate-cylindrieal, quite convex on the dorsum ; posterior lateral an- 

 gles of the metanotum robust, triangular ; margins of the mesoplurse obsoletely 

 crenulated ; abdomen of moderate size, of the length of the head and thorax taken 

 together, obtusely rectangular, quite convex on the dorsum and very densely punc- 

 tured; each lateral intramarginal area of the first dorsal segment cuneiform, 

 sprinkled with thick punctures, arranged almost alternately, margined, slightly 

 concave; third dorsal segment short, entirely depressed, convex; anteapical series 

 with numerous, rounded, unequal foveolse, that is to say, larger, of moderate size 

 and small: apical teeth acutely triangular, unequal in size, the two intermediate 

 ones larger and more robust, the two secondary ones of moderate size, the two ex- 

 ternal ones shorter and a little broader; emarginations also unequal, the central 

 one large, triangular, deep; the secondary ones of medium size, moderately and 

 somewhat obliquely arcuate, the two external ones small, also obliquely arcuate." 

 Evidently very distinct. Is it not possible that the locality may be 

 erroneous, and that this is not a North American species ? 



STIL.BUM Spinola. 

 Ins. Ligur. i, 9, 1806. 



The genus is sutEciently characterized in the generic key. As far as our 

 present knowledge of the North American species extends Chrysis and 

 Stilbnm, while having many characters in common or in close resemblance, 

 have also a correlation of differences that show them to be quite distinct 

 and very strongly marked genera. How they may approach each other 

 by the modifications of erotic species, I have had no means of determining. 



Stilbiiin aineth.ystiiinni. 



Chrysis ameihi/stina Fabr., Syst. Entom. ii, 359, 1793. 



Siilbum spJendidum Brulle, Hist. Nat. des Ins. Hym. iv, 15; Pahlb., Ilym. 



Eur. ii, 358, pi. xii, fig. 114 (not Fabricius). 

 Stilbum calens Spin., Ins. Ligur. i, 19, ISOfi; Brull6, loc. cit. 16; Dahlb., 

 loc. cit. 360; Eadoskovsky, Horse Soc. Ent. Ross, iii, 308, pi. vi, fig. 35. 

 Stilbum Wesmaeli Dahlb., loc. cit. 359, plate xii, fig. 115, 1854. 

 Stilbum amethyntinum Smith, Trans. Ent. Soc. Lond. 470, 1874. 

 A single specimen from Ontario in M. Provancher's collection. It 

 agrees perfectly with Dahlbom's figures, etc., and with Brulle's descrip- 

 tions. For its diflPering from the true S. splendidum^ of Fabricius, I 

 take Smith's determination. This specimen may be described as follows : 



