1895.] The Affinities of the Lepidopterous Wing. 717 
This method of tying by hooks is a common one among the 
caddice-flies. Often there will be no chitinized ridge (chiefly 
produced by an extra thickening of one or more of the anal 
veins) for the hooks to grasp, but one of the anal veins will 
bear a series of stiff hairs or bristles which interlace with the 
hooked bristles and project in such a direction that they are 
effectually grasped by them. In connection with the hooks 
and slight overlapping of the wing margins, there is usually a 
well-developed jugum, which makes a firm overlapping con- 
nection between the bases of the wings. There are often, too, 
small bunches of strong, long hairs, or smaller number of still 
stronger hairs borne on the base of the costal margin of the 
fore wing, which project forward under the jugum, suggesting, 
as shown especially in Hallesus, the beginnings of the lepidop- 
terous frenulum. 
Raita itive 
anita 
Fic. 9. e Portions of wings of a caddice-fly; a, anal margin and area of fore 
wing; b, basal half of costal margin and area of hind wing; c, hook (enlarged) 
from costal margin of hind wing. 
A most interesting wing tying arrangement is presented by 
Panorpa (see Fig. 10, a, b, c). We have here an arrangement 
which is strongly suggestive of what that racial type-structure 
may have been from which, on the one hand, the successfully 
functioning unaided jugum, and on the other, the perfected 
frenate arrangement could have been developed. The pretty 
