27 
gy. Median labial lobe entire; female without genital 
valves. Gomphide. 
J. Eyes but little separated, or meeting at a single point 
dorsally ; median labial lobe bifid. 
Cordulegasteride. 
c. Triangle of front wings with its long axis at right angles 
to the length of the wing; triangle of hind wings with 
its long axis coincident with that of the wing; ante- 
cubitals of the first and second series mostly coinci- 
dent ; second series of posteubitals incomplete at in- 
ner end. Libellulide 
Faminy PETALURIDA. 
About all we know of the biology of this interesting fam- 
ily is contained in two late papers by Williamson (00a, ’01) on 
the recently discovered nymph and habits of the adult of our 
single North American species, Tuchopteryx thoreyi. This is 
eastern and southern in its range, and has been found in an 
adjoining state, Kentucky. While the adult has usually been 
grouped with the Gomphidew, the nymph is nearest to the 
ZEschnide, although it approaches nearer to both the Cordu- 
legasteride and Gomphide than any other known form, possess- 
ing a remarkably synthetic combination of characters. The 
adults were observed, according to Williamson, ovipositing in 
boggy ground along a small hill-stream, where a single nymph 
was found emerging. 
Famity ASSCHNIDA. 
The elongate nymphs of this family have a flat labium very 
much like that of the Gomphidw, consisting of a long mentum 
bearing at its extremity a pair of curved appendages (the lat- 
eral lobes) like the mandibles of a beetle, more or less toothed 
on the inner edge and armed outwardly, toward the apex, with 
a strong movable hook. The apical tooth of these appendages 
is always present, not terminal and curved inward as in Gom- 
phide, bat rather on the inner side of the squarely truncate or 
