662 Wisconsin Academy of Sciences, Arts and Letters. 
broader, often with one or two pale clots at the thyridium, and 
frequently (in strongly marked individuals) connected with a 
brown space (more or less broken up into irrorations) at the 
angle, sometimes occupying nearly all the apical portion, and 
limiting externally the anastomosal space, which is usually not 
very distinct, and sometimes has darker irrorations in it (in 
pale individuals the wings have no dark markings, and the 
fenestrate spot in them is less distinct, and the anastomosal 
space obsolete) : no pterostigma: membrane with very sparse 
and short grey pubescence: neuration scarcely darker, with 
short grayish hairs. Posterior-wings whitish hyaline, the apical 
portion tinged with yellow; neuration pale, yellowish in the 
apical portion: the first apical sector in the male with a dense 
fringe of brown hairs (the ‘beard’) occupying only a short 
:space: upper branch of the cubitus furcating slightly beyond 
ithe level of the commencement of the discoidal cell. 
“In the male the terminal margin of the last (eighth) dorsal 
segment is much produced in the middle into an obtuse lobe 
which is somewhat rolled under and densely covered with short 
black setse. Superior appendages very large, elongately oval, 
yellow, very convex externally, and with the upper and lower 
margins considerably rolled inward; the lower margin is black 
and coarsely but obtusely toothed, and in the middle of this 
margin (or rather nearer the apex than the middle) is a very 
large black triangular projection turned inwards, and coarsely 
toothed in a very irregular manner, fringed with long pale 
hairs (the form of this projection varies in individuals) : in¬ 
ternally these appendages are deeply concave. Intermediate 
appendages lying deep in the cavity of the abdomen, short, ob¬ 
tuse, laterally broad, the apex obtuse and black. Side-pieces 
of the last (ninth) ventral segment broad, fringed with long 
pale hairs. Inferior appendages short, sub-triangular, with 
long dark hairs at the apex. Penis elongate, reddish. A mi¬ 
nute acute triangular tooth in the middle of the 6th and Tth 
ventral segments. 
“In the female the 9th dorsal segment forms a triangle, 
fringed with pale hairs. Appendages long, drawn out into a 
slender point, with long pale hairs, the basal portion broader 
