LUCY WRIGHT SMITH 
467 
the posterior end of which is surrounded by a membranous cover- 
ing studded laterally and ventrally with minute, triangular teeth ; 
the lateral stylets (fig. 45, L. S.) are flat, elongate lobes with 
pointed tips. There is nothing unusual in the form of the para- 
genital plates (fig. 45, P. G. P.) or in the connections with the 
other parts. Although the form of the median stylet is very 
different from those just described, it probably functions in the 
same way. In copulation, if the end of the abdomen were 
arched dorsalward sufficiently, it would bring the pointed pos- 
terior end, anterior in position and it would be introduced into 
the vagina first. The rough membranous sheath, covering this 
portion of the stylet, is a further indication that it is the probe 
end. It is possible that the entire stylet is extended into the 
vagina; its triangular shape would make it an excellent wedge 
for prying open the passage. 
Key to Genera of Perlodini 
Adults 
a. In the fore-wing an apical network of cross-veins extending from costa to 
cubitusi Protarcys 
aa. In the fore-wing an apical network of cross-veins of lesser extent. 
b. Costal margin of the wing showing a slight concavity at the humeral 
cross-vein; the length of the inner inter-radial cell at least twice as great 
as its base (p. 475); the network of cross-veins restricted to the anterior part 
of the wing, chiefly between radius and the branches of the sector. 
Arcynopteryx 
bb. Costal margin of the wing not showing a slight concavity at the humeral 
cross-vein; the length of the inner inter-radial cell only a little greater than 
its base. 
c. A rich network of cross-veins extending from costa to mediai. 
Megarcys signata 
cc. A scanty network of cross-veins restricted to the region between 
radiuS 2 and mediai Dictyogenus? phaleratus 
PERLODES Banks 
1903. Perlodes Banks, Ent. News, XIV, p. 241. 
1912. Perlodes Klapdlek, Coll. Selys, 4: 31. 
In giving the distribution of the genus Perlodes, Klapdlek says 
that it is spread over Europe and is represented in America by a 
single species. Among his specific descriptions we find on page 
40 a sketch bearing the legend ^‘Perlodes transversa Kip. (Nord 
Amerika),” but he gives as the basis for the description one 
TRANS. AM. ENT. SOC., XLIII. 
