700 Wisconsin Academy of Sciences, Arts and Letters. 
transverse spots, one pair immediately anterior to the other; 
laterad may be seen two oblong dark spots ventral to each eye, 
with two more arranged parallel to these. A narrow bar along 
edge of occipital foramen on either side below. Prothorax 
nearly clear with short narrow bar along anterior edge on either 
side of the median line; a pair of oblong spots parallel to median 
line about the middle of the segment; a group of 10 or 12 dark 
spots on the outer posterior portion of this segment, the two 
inner ones of the group being elongated in the direction of a 
slightly diagonal line, the others forming a more or less perfect 
circle about one of the number as a center. Mesothorax with 
dorsal chitinous shield not distinctly delimited; near the an¬ 
terior edge a pair of transverse spots; at juncture of middle and 
posterior thirds a smaller pair of longitudinally oblong spots, 
and near the posterior edge another pair of transverse spots, 
slightly nearer the median line than the first pair; six smaller 
spots lie outside these marks on either side. Metathorax not 
chitinous. Legs yellowish, with two or three brown spots on 
each coxa; the second leg is peculiar, being modified apparently 
for grasping; the third leg is a typical swimming leg. Ho gills 
or lateral line. Ho median dorsal plate on the 9th segment. 
Pupa. —Length, 7-8 mm. Width, 1 mm. Body bright green 
in life. The long antennae are coiled about the posterior end 
of the body, passing about twice around in the female and six 
times in the male; a few hairs pointing forward to hold them 
in place. Dorsal spines, III, 2. 2. 2 + 2. 2, VI. Ho gills 
and no lateral line. A double line of chi tin on both dorsal and 
ventral sides of the abdomen. On the tergum of the 1st seg¬ 
ment, a lateral border of yellow chitin, ending in a knob studded 
with a few blunt spines. The 9th segment is long and slender, 
and in somewhat advanced stages the genitalia of the imago 
may be seen some distance forward of the extremity; this pos¬ 
terior part, which is thus left empty, is more strongly chitinized 
so as not to become useless in the later stages. The segment 
is terminated distally by a pair of long spiniform processes, 
bearing bristles and small spines on the proximal portions, 
slightly upturned at the extremities; viewed laterally these are 
seen to arise from the ventral portion of the extremity of the 
