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Fig. 
Annals Entomological Society of America [Vol. VIII, 
EXPLANATION OF PLATES X AND XI. 
All figures drawn with a camera lucida. In all drawings the upper surface of 
the wing is to the left. 
Cu., cuticula. 
Tr. S., trichogen of surface hair. 
Tr. V., trichogen of vein hair. 
V., vein. 
1 
2. 
Transverse section of a large vein hair. X 1700. 
Transverse section of one of the very long hairs found on the posterior 
wings. X 1700. 
.3. Section through one wall of the wing from a pupa after the last larval skin 
ood. 
ig. 12. 
ig. 13. 
ig. 14. 
ig. 15. 
10. 
has been cast and the body has started to contract. The cells of the 
hypodermis are as yet all similar and at no place in the section can 
any enlarged nuclei be found. X 1700. 
Section of a little older stage showing part of a vein, V, adjacent to 
which is an enlarged cell and nucleus, the beginning of a vein-hair 
trichogen, Tr. V. X 1700. 
A slightly older stage, after the wing has started to fold, showing three 
normal hypodermal cells and a vein-hair trichogen, Tr. V., near 
which is one of the other nuclei which move out with the trichogen. 
X 1700. 
A still older stage showing the enlarged nucleus of the vein trichogen. 
The greatest change over the preceding figure is in the much enlarged 
nucleole of the trichogen nucleus. X 1700. 
Section of a wing which does not as yet show the final folding. The 
nucleole shows the change from the single large one of the preceding 
stage. The cytoplasm of the trichogen is seen to be much darker than 
of the normal hypodermal cells and is extended out for some distance 
in the beginning of its development. Cuticula not drawn. X 1100. 
Section of a wing which has decreased very much in thickness. One 
vein-hair trichogen and two of surface hairs on upper surface. Middle 
membrane, M..m., through center of wing and connected by pro-- 
toplasm to both surfaces. Cuticula not drawn. X 875. 
From transverse section of a wing of an imago soon after its emergence. 
Shows one vein hair and how the vein as well as other surface is 
covered by the small surface hairs. X 600. 
Four normal and one enlarged hypodermal cell, the latter has wandered 
a short distance towards the center of the wing and away from the 
surface; this enlarged nucleus, Tr. S., will later become that of a tri- 
chogen from which will develop one of the large surface hairs. X 1700. 
Two trichogens, Tr. S., of enlarged surface hairs showing the beginning 
of hair development. Cuticula not drawn. X 1100. 
Surface view of wing of about same stage as preceding. Four trichogens, 
Tr. S., and several normal hypodermal nuclei are shown. X 1100. 
Section of wing of pupa, wing folded within cuticular covering. One 
large and two small surface hairs. X 1700. : 
Section showing one large and two small surface hairs. From an imago 
just after its emergence. X 1700. | 
Three small surface hairs, from folded wing shortly before emergence of 
imago. X 1700. 
