204 Wisconsin Academy of Sciences, Arts, and Letters. 
7. de Geer, C. Memoires pour servir a l’histoire des insectes. 
Stockholm, 1752. 
8. Giarrm, E. Account of a singular conformation in the wings of 
sc^e species of moths. Trans. Linn. Soc. Lond. 1: 135. 
1791. 
9. Griffith, G. C. On the frenulum of the Lepidoptera. Trans. 
Entom. Soc. Lond. 1897, p. 121. 
10. Harris, M. Tendons and membranes of the wings of butterflies. 
London, 1767. 
11. Kirby, W., and Spence, W. An introduction to entomology. 
London, 1815. 
12. Meyrick, E. Handbook of British Lepidoptera. London, 1895. 
13. Poey, P. Ann. Soc. Entom. France. 1: 1832. 
14. Tillyard, R. J. The wing-coupling apparatus, with special refer¬ 
ence to the Lepidoptera. Proc. Linn. Soc. New South Wales. 
43: 286. 1918. 
15. Westwood, J. O. Introduction to the modern classification of 
insects. London, 1839-1840. 
Explanation of Plate I 
Fig. l. 
Fig. 2. 
Fig. 3. 
Fig. 4. 
Fig. 5. 
Fig. 6. 
All figures drawn with a camera lucida. 
View of the frenulum-bearing area of a wing, young speci¬ 
men of male pupa, showing the enlargement of several of 
the hypodermal cells. Near the free surface can be seen 
a number of normal cells of the hypodermis; these are in 
reality between the enlarged cells. X 18 6. 
View of the same area from an older male pupa. The frenu- 
lar lobe has not yet formed, and part of the trichogens are 
not seen. The prolongation of the cells beyond the sur¬ 
face is shown; as yet they are separated from each other. 
X 146. 
Drawing of the frenular lobe of a still older male pupa. The 
prolongations of the cells are not drawn throughout their 
entire length, but they have in part fused to form the 
single large bristle characteristic of the male moth. Cellu¬ 
lar divisions and nuclei of hypodermal cells not drawn. 
X 186. 
The frenular area of a young female moth of about the same 
age as that represented in figure 2. The three enlarged 
hypodermal cells are clearly seen. X 18 6. 
Section through the frenular area of the pupa of a female 
moth. The three large trichogens are shown and the 
normal hypodermal cells. The bristles developing from 
the trichogens have not been drawn. Cuticula shown. 
X 146. 
A single trichogen from the pupa of a female moth; the 
bristle is cut near its base. X 186. 
