1915] Wing Hairs of Platyphylax Designatus tao 
the folding of the wing. The circular raised ring into which 
the hairs fit is smaller and less noticeable than the similar part 
for vein and marginal hairs. These surface hairs have a pointed 
distal end, with this exception their diameter changes but little 
and they do not become widened at the base. 
3. small surface hairs. These are very numerous and are 
scattered regularly on the surface, vein and margin. They are 
all nearly equal in size and are bent or hooked near the tip. A 
surface view of any part of either wing shows that these hairs 
come from nearly all of the hypodermal cells which have not 
taken part in the formation of one of the larger hairs. 
4. The longest hairs are near the base of the posterior wings, 
they are much longer than the others and are present upon the 
surface and on the veins. These long narrow hairs are of equal 
diameter throughout except the pointed distal end. The ring- 
like cuticular thickening into which each hair fits is not directly 
upon the surface but situated upon a rounded papilla. In 
transverse section these hairs are seen to be fluted, much more 
deeply so than the large ridged vein hairs; the number of raised 
ridges varies from five to eight although. six is by far the most 
constant number (Fig. 2). 
When the pupa of Platyphylax designatus emerges from the 
last larval skin the wings are found at the sides of the thorax 
extending down against the legs and by these held from further 
extension in a ventral direction. In a surface view the wings 
are seen to have several longitudinal folds, Marshall (Fig. 23), 
and in section to have a fluted appearance along both surfaces. 
The wings soon begin to unfold and straighten until they are 
extended backward along the sides of the abdomen, Marshall 
(Fig. 25). The thickness of the wing does not at first decrease 
and in section the cells of the hypodermis are seen to be arranged 
in a fairly regular, single layer over the entire surface and just 
inside of the cuticula. The wings in their continued growth 
back over the body begin to decrease in thickness and at about 
this time there first appear those enlarged hypodermal cells from 
which the vein and marginal hairs develop; these are soon fol- 
lowed by the other enlarged cells between the veins from which 
the large surface hairs are formed. 
Vein hairs. Just before the appearance of these above men- 
tioned cells the hypodermis occupies a fairly even layer just 
