125, 
the anterior wings, has by some authors been considered to represent 
the episternum of the metathorax. <As already indicated, it is inti- 
mately fused with the mesothorax, and its place here is still further 
shown by its relation to the anterior wings. The epimeron of tbe 
metathorax is comparatively small, and the episternum is apparently 
wanting, unless the sclerite just above the metepimeron may be so 
considered. 
The leg includes a large coxal joint, 2-jointed trochanter, and the 
femur, tibia, and tarsus occurring in the order named. In two genera 
the legs are characteristically shaped—Cresus having the apex of the 
hind tibiee and the metatarsus broad and flattened, resembling the con- 
dition obtaining in social bees, and /folcocneme having these parts 
somewhat enlarged and the posterior tibiw distinctly grooved exteriorly. 
This last character is, however, present in other genera, though less 
distinctly. The tibial spurs, of which there are two at the apex of each 
tibia, do not vary sufficiently to be of much value in generic or specific 
descriptions. The forward one of the anterior pair of legs is much 
stronger than the others, and doubtless serves the role of an antennal 
scraper, as does the corresponding spur in other Hymenoptera. 
The claws, while affording primarily generic characters, are of some 
value in the characterization of species. Three distinct types of claws 
are noted, viz, the first, in which the claw is 
more distinctly cleft, the two teeth, which 
have been termed rays throughout the de- 
seriptions, extending in a direction nearly 
parallel, the inner ray being commonly not 
much shorter than the outer (fig. 4, d, e, f); ? 
the second form of claw consists in the pro- 
jection of a minute tooth well within the ; 
apex of the claw and extending nearly at 
right angles to the claw (fig. 4, b, ¢); and the 
third, a simple claw, without br anch or tooth ( 
(fig. 4, a). 
The abdomen is ovate or elliptical, less : 
5, Fic. 4.—Types of claws: a, Gymno- 
commonly elongate, as in Hwura, and faeaile Ten caaforieoe ht Pechinena 
more or less depressed. It presents in the tus eatensicornis; ¢, Lyg@onematus 
fe 1 é farealbar ifth llitecnn l erichsonui; d, Amauronematus luteo- 
emale nine dorsal ares, if the small terminal j.,jm, ¢, Pteronus cornelli; f, 
sclerite attached to the large overlapping — Pontania agilis (original). 
eighth are is considered to be distinct. This last sclerite, the ninth, 
bears laterally within the margin at its base the two unjointed append 
ages known as cerci. The female has but six ventral ares, the terminal 
ones being metamorphosed into the ovipositor and its basal supports.! 
a ven prominent dorsal ares, with a thin anc 
The male abdomen has seve t dorsal , with a tl 1 
frequently concealed terminal arc, and seven ventral ares, the last 
(hypopygium) being ey long, more or less curved nee at the aie: 
1Por structure of ae organ in ee neteateee: see Proc. E = Soc. Wash. an II, p. 201. 
