342 BULLETIN UNITED STATES GEOLOGICAL SUEVEY. [YolY. 



posterior tibise flattened and dilated, the inner spur curved and almost 

 or quite equalling the basal joint of the tarsus in length. Legs of the 

 male not so stout and not so spinose; basal joints of the intermediate 

 tarsi not produced, the basal joint not dilated and not excavated; the 

 spurs of the posterior tibiaB not half as long as the basal joint of the 

 tarsus. Tip of the abdomen of the female with a well defined, elongated 

 dorsal area. Eighth ventral segment of the male armed with a stout, 

 curved spine, the tip of which is usually exserted, the rest of the eighth 

 segment concealed, but both the dorsal and ventral arcs form chitinous 

 plates. The clasi)ers of moderate size. Apex of the abdomen in both 

 sexes acute. 



Say, in describing grandis, pointed out the fact that that species, 

 together with speciosus, should be set apart from SUzus proper, and 

 gave, as a character to separate the two groups, the absence of a spine 

 at the tip of the abdomen in the males of the larger species. Say's 

 figure of grandis i represents the abdomen in a contracted state. It is 

 therefore probable that the spine, being withdrawn, was overlooked by 

 him ; for the central spine is large in Sphecms, but is capable of being 

 withdrawn out of sight, as are also the three spines of Stizus unicinctus. 

 Both Dahlbom and Lex)eletier separated the genera on account of dilfer- 

 ences in venation. 



IJnless the Australian Stizus pectoralis Smith (0. H. B. M. iv, p. 337, ?, 

 and Cruise Curagoa, pi. xliv, f. 6, 1873) belongs here, this genus apx)ears 

 to be exclusively American. 



Sphecia Hlibner (1816) does not seem sufficiently like ^^Sphecius^^ to 

 invalidate the latter name by its priority; but if it did, Hogardia, and 

 not Stizus, should be used. 



1. Spkecius speciosus. 



Sphex spedosus Drury, Exotic Ins. ii, 71, t. 38, f. 1, $ (1773). 



Vespa iricincta Fabr., Ent. Syst. ii, 254 (1793); Syst. Piez. 254 (1804). 



Stizus speciosus Lepel. et Serv., EucycL M6tli. x, 496, t. 382, f. 6, 5 (1825). 



Stizus speciosus Westwood's Ed. Drury, Ex. Ins. ii, 77, pi. xxxviii, f. 1, 2 (1837). 



Stizus speciosus Blanchard, Diet. Univ. d'Hist. Nat., Atlas, vol. ii, Hym. pi. 2, f. 

 3, ^,£7,5(1849). 



Stizus speciosus Smitli, Cat. H. B. M. iv, 336 (1856). 



Stizus spedosus Pack., Proc. E. S. P. vi. 442, 9 (1867). 



Stizus spedosus Walsh, Am. Ent. i, 129, f. 103, and ii, 87, f. 57, $ (1869-70). 



Stizus speciosus Wood, Ins. Abroad, 473, f. 252, $ , f. 253, $ . 



Sphecius speciosus Dahlb., Hyra. Eur. i, 154, 9 (1843), and i, 480, 9 (1845). 



Hogardia spedosa Lepel., Hym. iii, 290 (1845). 

 Var. 6. Stizus grandis Say, West. Quart. Sep. ii, 77 (1823), and Am. Ent. p. 3, pi. 2, f. 1, 

 5,f.2, ^. 



Stizus grandis Pack., Proc. E. S. P. vi, 442, 9 (1867). 



Stizus grandis Eiley, First Ann. Eep. Ins. Mo. 27, f. 12, 9 (1869). 



Stizus grandis WalsL., Am. Ent. i, 8, f. 3, 9 , and 129, f. 102, 9 (1869). 

 Var. c. Stizus fervidus Cress., Trans. Am. E. S. iv, 223, 9 (1872). 



The species is found from Connecticut to Texas. After repeated com- 

 parisons of specimens, I am unable to find any specific characters for 



