No. 395.] _ THE WINGS OF INSECTS. 857 
nuclei have come into contact with the basement membrane 
at the subsequent expansion of the wing, these, instead of 
retreating with their fellows to the chitine layer, seem instead 
to remain where they are, and to attract to themselves the 
slender prolongations of the neighboring cells. They thus 
acquire a stellate appearance, as shown in Figs. 89, B, and 
90, D. These seem to occur only in narrow spaces, in which 
great expansion has followed close crowding.! We have found 
them in Leucorhinia (Fig. 83) in the rapidly expanding anal 
angle of a wing, the greater part of which appeared as Fig. 
84, B, the cells having spindle-shaped bodies. We have seen 
them also in the anal angle of the wing of a pupa of Corydalis, 
1 
Fic. 90. — Diagram illustrating the behavior of the hypodermis during t 
wing: A, nearly normal hy yp PORON + B, the same, after being crowded wit ‘thin the wing fold; 
C, the same after the first of the wing; D,a pe NEEE upon the basem 
membrane; Æ, pirata of the hypodermal cells 
the pre-anal area being filled with the peaked cells more char- 
acteristic of that stage. 
The segregation of the hypodermis, which results in the 
accumulation of it around the tracheal channels and in those 
parts of the wing to be made strong by heavy deposits of 
chitine, takes place during the final stages. Some interesting 
illustrations of it are shown in Figs. 87 and 88, and are explained 
in the legends to the figures. These processes and the final, 
disappearance of the scattered hypodermal cells, wasting them- 
selves away in chitine formation, are the final steps in the mak- 
ing of the wing. 
The accompanying diagram (Fig. 90) will, therefore, repre- 
sent what we think may tairly be taken as typical for the 
behavior of ‘the hypodermis. While this strongly suggests 
1 This is the “ Grundmembrane” of Semper, which was believed by him to be 
formed by leucocytes during the pupal period, and, therefore, to be distinct from. 
the middle membrane of the wing of the larva. 
