18 JOURNAL OF ENTOMOLOGY AND ZOOLOGY 
BBB. Wings violaceous; antenne black, apex yellow; abdomen 
more or less black or entirely red, apex always red; legs 
except the posterior tibiew and tarsi yellow or more or less 
black. cressont Norton 
AAA. Abdomen entirely reddish or brownish yellow. 
B. Thorax red or brownish; antennx, legs, and abdomen yellow- 
ish red; wings yellow. é californicus Norton 
BB. Thorax, head, base of antenn, and more or less of legs, black; 
wings violaceous. g and variety of ?cressonit Norton 
BBB. Thorax except metanotum black; apex of abdomen dusky. 
(See 6 taxodu.) 
Urocerus flavicornis Fabricius 
(Figs. 8 and 26) 
1781 Sirex flavicornis Fabricius, 9. Spee. insec.; v. 1: p. 418. 
1835 Sirex bizonatus Stephens, @. Illus. Brit. ent.; v. 7: p. 114; pl. 
BO, thy 2 
<1841 Urocerus abdominalis Harris, ¢. Rep. ins. Mass. inj. to veg.; p. 
392. 
1874 Sirex latifasciatus Westwood, ¢. Thes. ent. oxon.; p. 114; pl. 21, 
ifs 2 
1893 Urocerus riparius MacGillivray, ¢. Washington Tenthred. and 
Uroceride. < Can. ent.; v. 25: p. 244. 
This handsome insect is our commonest species of Urocerus 
There is no doubt that the male described by Harris as abdom- 
inalis is in part the male of this species, and also probably in 
part of albicornis. In a series of over fifty males I find five 
that possess but a single spur on the apex of the posterior 
tibie, a character that would place them in the subfamily 
Tremicine according to Ashmead’s classification. 
Kirby says that bizonatus differs in the lighter color of the 
hind legs and the color of the abdomen, but specimens of /lavi- 
cornis show this same variation. 
The North American flavicornis is very closely related to the 
European gigas. The difference may be expressed by the fol- 
lowing table: 
