29 
each femur and tibia, a pale mid-dorsal abdominal line, and the 
apical margins and hind angles of abdominal segments and the 
tips of abdominal appendages also pale. 
The imagos are like the Libel/u/ide in the great develop- 
ment of the eyes, which touch for some distance along the 
middle of the head, and in the presence of a roughened carina 
on the sides of the abdominal segments. The nearness of the 
lowest forms of this family and the Libel/ulide in wing vena- 
tion and nymphal sculpture is evident; but the Mschnide as a 
whole are much nearer the primitive stock by reason of several 
characters, especially the structure of the labium and gizzard, the 
general form of the nymph, the form of the egg, and the manner 
of oviposition. The wing triangles are elongate lengthwise of 
the wing, as in the Gomphide, usually with several cross-veins; 
most of the antecubitals not coincident. The female is provided 
with an ovipositor, by means of which the elongate cylindrical 
eggs are inserted into various plants and substances in the water 
instead of being washed off by dipping the abdomen during 
flight as are the more or less oval eggs of the other An/soptera. 
Even in the nymphs the developing ovipositor, on the eighth 
ventral abdominal segment, is well marked and recognizable in 
all but very young individuals. In the males the corresponding 
parts are more difficult to see, but this sex possesses a very 
evident scale-like piece overlying the base of the superior ter- 
minal appendage. 
Mr. Needham has observed that the eggs are deposited in 
the stems of plants, in floating timbers, in piers, etc., at or very 
near the surface of the water, either above or below it, but 
always in moist tissue. He has floated pieces of decaying wood 
upon a pond asa means of obtaining wschnid eggs, and these 
proved very attractive to the ovipositing females. 
The usefulness of the imagos, especially Anaxr Junius, on 
account of the enormous quantities of pestiferous gnats and 
mosquitoes which they destroy, puts them among the particular 
friends of mankind. 
