88 Alderson: Notes on Chrysopa perla and C. flava. 
cocoon. This last remained in the same position until about 
2 p.m., when it freed itself, and to my surprise, instead of 
gradually developing into a perfect insect, remained enveloped 
in a thin, transparent pellicle. Soon after this it apparently 
lost its hold of the cocoon, and began rolling about at the 
bottom of the jar in its efforts to find some object to which to 
attach itself. I placed it on a piece of twig, but it seemed 
quite unable to cast off its sub-imaginal skin, and after two or 
three days, as it gradually got weaker, I dropped it into a tube 
of formalin for preservation. 
One other imago emerged after this, but the time elapsing 
between the emergence from the pupa case and the casting of 
the sub-imaginal skin is evidently very short in a healthy speci- 
men, and I was not fortunate enough to see it. The pupa case 
appears to open by means of a small lid at one end. The cast 
skins are perfectly transparent, and consist of the covering of 
the body, legs, and head. The thorax splits, in order to allow 
the insect to emerge. In the sub-imago the wings are only 
3 mm. in length, the fore wing appearing slightly shorter than 
the hind wing, and resting above it. The antenne are quite 
short, and are folded vound the eyes like a ram’s horns. They 
appear to lengthen rapidly, and when fully extended remain 
curled underneath the body. I could not help wondering if 
this lengthening of the antennz might not throw some light on 
the subject with regard to the genus Ade/a in the Micro- 
Lepidoptera. It has always puzzled me, and perhaps others, 
how the long antennz in this genus can be folded in the pupa 
case. Might not this lengthening out be a possible solution of 
the mystery ? 
The eyes of the sub-imago are of the same bright green as 
in the perfect insect, the body also of the same shade, and the 
bright yellow line on the thorax as distinct as in the full 
emergence. The wings also show their iridescence through the 
thin membrane that covers them. 
I feel uncertain if this stage ought to be regarded as a part 
of the pupal existence or as a true sub-imaginal one. I can find 
no information about it in the books I have, so I have preferred 
to call it the latter, especially as it seems to me to represent a 
distinct stage in the life history. It is evidently of very short 
duration in a healthy subject, as except in the case of the insect 
which I preserved, I never saw any of the others except as 
imagines. 
Emergence seemed to always take place in the morning. 
Naturalist, 
