Fussorial Ilymcnoptcra of North America. 71 



unequal large broad spines. Tarsi short, first joint hardly shorter than 

 remaining joints. 



9 . Fore femora trigonate, as usual, not being flattened. Tibiae 

 smooth, large, terminating in short spines, with a slender spur. Tarsi 

 long and slender. First joint of tarsi spinulose without, shorter than 

 the remaining joints. Middle and hind tibiae swollen and slightly 

 tubereulated on the outside, the tubercles are hardly spinose and not 

 arranged in rows on the hind pair. 



% . Abdomen a little sborter than the head and thorax together. It 

 is broad and flattened, and slightly arcuated. Abdomen tip subacute, 

 tip triangular with an incomplete sub-basal depression above. 9 

 broader tban % ; tip mucrouate, triangular above, depressed, bounded 

 by lateral ridges. 



The body is in places under the limbs covered with a long silky pu- 

 bescence. The head does not narrow so rapidly behind, and the second 

 joint of the antennas is not so long; the simple fore legs, the more flat- 

 tened and broader thorax, the mucronate broad flattened abdomen at 

 once distinguish it from Thyreopus or from Ceratocolus. 



The above description applies to the more typical species of the 

 group which Crahro (5-maculatus represents. 



Group (A) of which G. interruptus St. F. is the type, comprises 

 Cerceris-like species, and connects with Cerceris by Anacrabro. 



Synopsis of the Species. 

 A. Species of moderate size, bodies coarsely punctured. 



a. Basal ring of abdomen with fascia;. 



% . Head trapezoidal, sides narrowing behind, antenna 

 untoothed; abdomen with three pairs of fasciae 

 and two terminal bands. J. Head cubical, body 

 broad and short; antennae short C. interruptus, St. F. 



b. Femora sinuate on edge. 



Front elongated, thorax entirely black C producticollis, Pack. 



%. Four basal joints of flagellum dentate; three pairs 

 of fasciae and three terminal bands. J. No yel- 

 low markings on meso-notum, antennae slender. .C. bellus. Cresson. 



%. Head narrow, flagellum not dentate; head and 



thorax very black C. atrifrons, Cresson. 



% . Head broad; mandibles yellow; antennae not den- 

 tate; abdomen with five terminal bands; two 

 dots on basal ring C. odyneroides, Cresson. 



c. Basal ring immaculate ; of small size. 



% . Antennae once-toothed ; abdomen with three ter- 

 minal bands C. honestus, Cresson. 



% . Antennae many-toothed; abdomen with two termi- 

 nal bands C. gracilissimus, Pack. 



