ZETIIUS. 31 



about the end of the petiole. These are the Z. spinipes Say ( ? ), 

 and the Eumenes pensylvanica Hald. (%)■ 



d. Quite black; the clypeus margined with yellow (%) (Mis- 

 souri ; Edw. Norton). 



The punctures vary quite notably among this species. The 

 head and the thorax are very coarsely cribrose ; with the ?, the 

 clypeus is strongly rugose; the vertex often becomes shining 

 from use. Among the 9, the clypeus is less strongly cribrose. 

 The second segment is sometimes hardly at all, sometimes quite 

 strongly punctured. A specimen from Florida has the swelling 

 of the petiole very coarsely cribrose. 



Bess. a. diff. — Easily recognizable by its size, which is superior 

 to that of all the following species, and by its violet wings. 



Hub. United States. Conn., Pa., Ill, Term., Ind., Pla. (14 ?, 

 6%). 



Not a. — As I have already said (loc. cit,), the description given 

 by Say is very defective, and calls for an interpretation. When 

 this author says : "Peduncle rather slender," it is without com- 

 parison with the other species, the most of which he did not 

 know. The " piceous dentate band of the margin of the peduncle" 

 is but the subjacent double margins, which do not make it dentate 

 except in the color. The " posterior margin abruptly and 

 smoothly impressed of the 2d segment," alludes to the subjacent 

 lamina on the border of the segment which are salient in almost 

 all the insects of this genus, and which appear like a more dis- 

 tinct border than the veritable margin of the segment, which has 

 the yellow band. By " tibiae spinous behind-," the author means 

 without doubt the posterior extremity (which offers a very short 

 border) armed with -stylets common to all the Vespides. (From 

 this the name spinipes.) Finally, the author says that the second 

 segment "has a distinct neck at base," which signifies a very short 

 neck, for if it had been long, the word distinct was out of place. 

 This species is not then a Didymogastra, but really a true Zethus 

 (or Zethuscidus), which makes us think, that it really is, without 

 any doubt, the present species 



19. Z. sjiiiiosiBS Sacks. (Fig. 2, 2a.) — Parvulus, niger; capite, tho- 

 race et petiolo grosse percribratis ; clypeo integro, J nigro-sericeo, £ 

 flavo ; fronte carina transversa et linea flava ; pronoti margine crista- 

 tissimo postscutelloque spinoso fascia flava ; petiolo cylindrico, rugoso, 



