1915] Wing Hairs of Platyphylax Designatus 159 
face hair has not been formed. The amount of secretion neces- 
sary for the formation of one of these hairs is comparatively 
small and no change is noticeable in the nuclei of the cells from 
which they come. 
Upon the emergence of the imago these cells, as well as the 
trichogens of the larger hairs, decrease in size, loose their 
regular form and become small, irregular nuclei lying, as a rule, 
flat against the cuticula (Fig. 14). 
BIBLIOGRAPHY. 
Berlese, A. Gli Insetti. Vol. I, p. 48. 
Deegener, P. Haut und Hautorgane. From Handbuch der Entomologie 
herausgegeben von C. Schroder. Vol. I. 1st. Lief. p. 5. 
Dewitz, H. Ueber die Flugelbildung bei Phryganiden und Lepidopteren. 
Berl. Entom. Zeit. Vol. XXV, 1881. 
Kruger, E. Ueber die Entwicklung der Fligel der Insekten mit besonderer 
Berucksichtigung der Deckfligel der Kafer. Inaug. Diss. Gottingen, 1898. 
Marshall, W. S._ The development of the wings of a caddis-fly, Platyphylax 
designatus. Zeit. wiss. Zool. Vol. CV, 1918. 
Mayer, A.G. The development of the wing scales and their pigment in butter- 
flies and moths. Bull. Mus. Comp. Zool. Harvard. Vol. XXIX, 1896. 
Schaffer, C. Beitrage zur Histologie der Insekten. Zool. Jahrb. Anat. Vol. 
III, 1889. 
Semper, C. Ueber die Bildung der Fligel, Schuppen und Haare bei den 
Lepidopteren. Zeit. wiss. Zool. Vol. VIII, 1857. 
Spuler, A. Zur. Kenntnis der Schmetterlingsschuppen. Sitz. Ber. Physik. 
med. Soc. Erlangen, 1895. 
10. Spuler, A. Beitrage zur Kenntnis der feineren Baues und der Phylogenie der 
Flugelbedeckung der Schmetterlinge. Zool. Jahrb. Anat. Vol. VIII, 1895. 
11. Tower, W. L. The origin and development of the wings of Coleoptera. Zool. 
Jahrb. Anat. Vol. XVII, 1903. 
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