218 NORTH AMERICAN SCELIPHRON (hYMENOPTERA) 



Body metallic blue black or blue green, sometimes with violet 

 reflections. Clypeus normally tridentate, but teeth vary in 

 size and shape. Metapleural sutures indistinct. Claws of pos- 

 terior tarsi unarmed. Petiole of abdomen somewhat variable in 

 length, but never as long as median segment. 



The genus Sceliphron was established, in 1801, by Klug, who 

 included five species under it, viz: spirifex, madras patanum, 

 lunatum,cyaneii)n and fuscum. In 1802,Latreille* established the 

 genus Pelopaeus, giving Sphex spirifex Linnaeus and S. lunata 

 Fabricius as examples, and in volume xiii of the same work (1805), 

 besides describing these species under Pelopaeus, mentioned that 

 Klug had called the genus Sceliphron. In 1843, Dahlbonr^ estab- 

 lished the genus Chalyhion, separating it from Pelopaeus on a 

 color basis, with violaceum Fabricius, zimmermanni new species, 

 and cyaneum Linnaeus as species, and at the same time included 

 spirifex, limatum and several other species under Pelopaeus. Two 

 years later, in his tabulation of species on page 432 of the same 

 work, he mentioned Pelopaeus as a genus, with Chalyhion and 

 Pelopaeus as sub-genera, since no additional characters could 

 be found to justify separation. Chalyhion remained under 

 Pelopaeus until 1880, when Patton*^ gave distinctive characters 

 in addition to color, sufficient in his opinion to establish 

 Chalyhio7i and Pelopaeus as separate genera, and with this the 

 writer agrees. 



It will be noticed that the species removed from Sceliphron 

 by Latreille are black and 3'ellow, while cyaneum remaining is 

 blue, and fuscum is apparently unknown to modern workers. 

 Accordingly the separation of Pelopaeus from Sceliphron leaves 

 cyaneum as its type, in accordance with recommendations k. 

 and n. of the International Rules of Nomenclature. Patton's 

 designation of cyaneum as the type of Chalyhion would therefore 

 make this genus a synonym of Sceliphron, as restricted l)y the 

 removal of the species placed under Pelopaeus by Latreille. 



Pelopaeus californicus Saussure is regarded by the writer as 

 conspecific with cyaneum, since he has examined a number of 

 specinuMis from California, all of which are similar to cyaneum, 



■* Hist. Nat. Crust, et Ins., iii, .3:34. 



"iHym. Eur., i, 1843, 21. 



« Prop. Bost. Soc. Nut. Hist., xx, 1880, 378. 



