1910] Forbes—Aquatic Caterpillars 225 
with it, with some doubt, the following early stages. At any rate 
they do not seem to belong to the described species, N. obliteralis. 
The larve noted by Dyar as perhaps of this species are almost 
certainly those of N. maculalis. 
Eggs. The eggs were quite like those of N. obliteralis, as described by Hart; 
.55 x .4.mm. 
Stage I. (From these eggs.) Head dark brown, body pale yellow, not differing 
from the adult; without gills. ‘ Sete proportionately longer than later, especially 
those at the posterior end, the subprimaries absent. Prolegs with fifteen crotchets, 
all of the same length, in a transverse ellipse. The alternation of lengths evidently 
appears with the second stage in Nymphula. Tracheze empty. The head seems 
about the same as later in structure, but the antenna apparently lacks the terminal 
joint. Length at hatching 2.5 mm.; diameter of head .2mm. They all died with- 
-out eating, though provided with leaves of Nymphza and Limnanthemum (laid 
on the latter), but they gathered on the Nymphea leaf in numbers. Possibly in 
the first stage they may feed on submerged stems. Immediately on hatching they 
scattered and swam toward the light, spinning a tangle of silk threads. 
Full-grown caterpillar. The full grown caterpillar is found in a nearly circular 
case, formed of two pieces of leaf of the yellow waterlily. It was large and roomy, 
and one piece of leaf was much larger than the other. It was filled with air. Before 
pupation the case was cut down to a diameter of less than 12 mm., and was more 
-densely lined with silk. It was left freely floating. The caterpillar did not differ 
in structure from that of N. obliteralis (Dyar); with crotchets of ventral prolegs 
widely interrupted inwardly and outwardly; and anal prolegs with a single short 
bar of 12 crotchets. It was pale yellow, with light brown head without any dark 
band. The first abdominal spiracle was considerably larger than the fifth, and 
the second was intermediate in size between the first and the third. Diameter of 
head 1.25 mm. 
Pupa. Deeper, brighter yellow than that of N. maculalis and N. obscuralis, 
the first of the open spiracles somewhat smaller than the other two. The hind 
leg cases reach but one third way to the tip of the body; the anal end apparently 
without any decided modification. 
7. N. vectusalis. I had the good fortune to breed through a 
single specimen of this species, which was described, with some 
doubt, by Packard in the American Naturalist, xviii. The cater- 
pillar is as described by him, so far as my notes go, with blackish 
brown head, and dirty gray body. It makes a case with decidedly 
rectangular shape, living the entire last stage and pupating in a 
single case. The figure by Packard exactly resembles my speci- 
men. The caterpillar is extensible, like that of the other Nymphule 
and Packard’s figure would represent it in full extension; when 
retracted it is no slenderer than the others. Before pupation the 
