1880 .] 
87 
(as in 0. incongruus , Smith), which are apparently wanting in the 
males of Plackburni, hut which may possibly depend on the attitude 
of the body at the moment of death (T. B.). 
15. Odynerus Plackburni , sp. n. 
Ody nevus rubritinctus , J 1 , Smith. 
(No. 33). — I have two males and one female of this species. 
From Kauai. Allied to the last, and of similar habits (T. B.). In 
his remarks on the last species, Mr. Blackburn points out the differ- 
ences between it and the present. In Mr. Smith’s description (New 
Spec. Hym., p. 135, last line) we should evidently read for — “two 
(spots) beneath wings, frequently united,” — “two (spots) beneath 
wings, almost united” (W. F. K.). 
16. Odynerus montanus , Smith. 
(Nos. 28 & 41). — Occurs high up on the mountains of Oahu 
(T. B.). 
17. Odynerus congruus, Smith. 
(Nos. 13 & 14). — Found in company with Prosopis Plackburni. 
The wings exhibit a brilliant violet iridescence in certain lights, not 
mentioned in the description (T. B.). 
18. Odynerus dubiosus , Smith. 
(No. 35). — Common near Honolulu and elsewhere on Oahu (T. B.). 
19. Odynerus agilis, Smith. 
(No. 34). — From Maui. Frequents flowers, but seems to be rare, 
as I hunted a long time for a series, and only obtained two speci- 
mens (T. B.). 
20. Crabro ajjinis , Smith. 
(No. 36). 
21. Crabro mandibularis, Smith. 
(No. 3). 
22. Crabro denticornis , Smith. 
(Nos. 1 & 2) — Nos. 1 — 3 taken at flowers on Maui, February, 
1878. I believe these to be all one species, as also a single female taken 
in company with them, having the abdomen much marked with yellow 
(T. B.). 
23. Crabro unicolor, Smith. 
(No. 29). — Very rare ; but occurs on Oahu and Maui, and proba- 
bly all over the islands (T. B.). 
