58 
Psyche 
[Sept.-Dee. 
nse and legs were free. Forty-two minutes from the start the 
nymph dropped down and stood beside the chorion. At this 
time the pulsations on the vertex could still occasionally be seen, 
and the bubble of air in the head extended anteriorly as far as 
the eyes. The segments of the abdomen were telescoping into 
their normal position. One hour after hatching started, the 
bubble in the head had almost completely disappeared. Several 
other individuals completed hatching in twenty-five and thirty 
minutes. The pronymphal exuviae bearing the egg burster al- 
ways remained partly extruded from the chorion. 
Postembryonic Development . — -The nymphs (Figs. 3, 5, 6) 
are buff with slightly darker appendages during the early instars 
and gradually become light brown. There are bristle-like setae 
on the head and thorax. The dull color of the abdomen gives 
this species a characteristic velvety appearance. The antennae 
are eight-segmented in the first instar (Fig. 3) and thirteen- 
segmented thereafter. The wing pads appear in the third instar 
(Fig. 5) and the forewings approximately double their length 
with each successive moult. The sexes of the sixth instar 
nymphs can easily be distinguished because the asymmetrical 
genitalia of the male show through on the dorsal surface of the 
abdomen (Fig. 6). The duration of the six instar periods was 
as follows: first, 2.3 days; second, 2.4 days; third, 2.4 days; 
fourth, 2.7 days; fifth, 2.8 days and the sixth, 4.4 days. Ap- 
parently the last instar period is longer than any of the others, 
which is also true in C. manteri (6). The measurements in the 
following table were taken from ten preserved specimens in 
each instar: 
Instar First Second Third Fourth Fifth Sixth Adult 
mm. mm. mm. mm. mm. mm. mm. 
Head width 0.190 0.250 0.293 0.375 0.450 0.507 0.552 
Antennal length 0.338 0.440 0.512 0.627 0.763 0.900 1.097 
Forewing length 0.094 0.175 0.333 0.616 1.607 
The complete nymphal period averaged 17.3 days with a 
minimum of twelve and a maximum of twenty-seven. The 
nymphal period could probably be lengthened still more if feed- 
ing conditions were poor, because this species, like Lachesilla 
nubilis (Aaron), eats the epidermis and mesophyll of the 
sheaths when fungus is scarce. The total length of all the life 
stages was usually about 53 days. 
