78 Dr. A. S. Packard, Jr's Revision of the 



Crabro atriceps, Cresson. 



C. atriceps, Cresson, Proc. iv. p. 483. C1865). 



Colorado Territory, (Coll. Eat. Soc. Phil.). 



Crabro odyneroides, Cresson. 



C. odyneroides, Cresson, Proc. iv. p. 481. (1S65). 



Colorado Territory, (Coll. Ent. Soc. Phil.). 



Crabro honestus. Cresson. 



C. honestus, Cresson, Proc. iv. p. 485. (1865). 



Colorado Territory, (Coll. Ent. Soc. Phil). 



C. nigrifrons, Cresson. 



C. nigrifrons, Cresson, Proc. iv. p. 482. (1865). 

 Colorado Territory, (Coll. Ent. Soc. Phil.). 



Crabro gracilissimus. n. sp. 



% . Head broad, transverse, rather short, a little more than one-half 

 as long as broad, narrowing but slightly behind ; surface broad, 

 slightly convex, ocelli arranged in a low triangle, front but slightly 

 channelled. Antennal grove well marked, on each side a thin, sparse 

 silvery pubescence. Sides of head converge rapidly towards the cly- 

 peal region which is narrow and long ; clypeus long as broad, being a 

 little longer than usual, sharply carinated ; mandibles black, antennae 

 short and stout, scape yellow, black above; second joint of flagellum 

 with two unusually large teeth beneath, third, fourth and fifth also 

 dentate, black. 



Prothorax with two short, high carinations which are yellow. 

 Body as well as the head finely though not minutely punctured, thorax 

 otherwise black, except the yellow tubercles. Meso-scutum puncto- 

 striated, especially posteriorly, as are the scutellum and especially the 

 meta-scutellum. Enclosure of the propodeum long, narrow sublunate. 

 with longitudinal, irregular coarse rugae, a few transverse coarse 

 ruga% with interrupted longitudinal rugae, making the sides appear 

 angular ; its surface covered with subquadrate fossae. Tegulae dark 

 ferruginous, wings clear not clouded ; nervures ferruginous ; femora 

 black, fore femora yellow towards tip beneath ; tibiae slender, yellow, 

 black within, posterior ones black externally at tip; fore and middle 

 tarsi yellow, black towards the ungues; hind tarsi entirely brown. 



Abdomen long and slender, equalling the thorax in length, no band 

 on the basal ring ; on second, two large fasciae, nearly meeting, two 

 succeeding pairs much smaller and farther apart ; on fifth and sixth a 

 continuous band; tip broad sub-spatulate, slighty hirsute. Beneath 

 a little paler on the edge of the wings and with a few sparse hairs. 



Length of body, .30, head and thorax, 15 ; abdomeu, .15 inch. 





