1895.] The Affinities of the Lepidopterous Wing. 715 
and hind wings united by a membranous lobe, the jugum, 
borne at the base of the inner margin of the fore wings. 
When the wings of Hepialus or Micropteryx are extended, “the 
jugum projects back beneath the costal border of the hind 
wing, which, being overlapped by the more distal portion of 
the inner margin of the 
fore wing, is thus held be- 
tween the two as in a 
vise.” The frenate Lepi- 
doptera have the two 
wings of each side united 
_ by the familiarly known 
frenulum borne at the 
Fic. 7. Seales from wings of Trichoptera; base of the costal mee a 
a, portion of fore wing of Mystacides puncta- of the hind wings, or by a 
renee ag soale hairs and bulbous andreco- substitute for a frenulum, 
larged; c, d, scales from fore wings of Seto- an expanded humeral area 
om s of the hind wings, by 
which a considerable overlapping of the wings is produced. 
The common occurrence of a jugum among caddice-flies (see j 
in Figs. 4 and 5), which is essentially the same structure pre- 
sented by the jugate moths, has already been referred to by 
Prof. Comstock as of interesting significance. The jugate 
method is, however, by no means the only mode of wing 
union among the Trichoptera. The jugum may exist coinci- 
dently with other uniting structures, or it may be entirely 
wanting, the tying together of the fore and hind wings being 
accomplished by the overlapping for a considerable space of 
the hind margin of the fore wing and the costal margin of the 
hind wing, or by a row of hooks projecting from the costal 
margin of the hind wing which fasten to a chitinized ridge 
running along near the hind margin of the fore wing. There 
seems even to exist the beginnings of the frenate method of 
wing tying, as displayed in Hallesus sp. The wings of this 
trichopteron present a combination of the jugate and row-of- 
hooks methods of wing tying, and, in addition, there are pres- 
ent on the base of the costal margin of the hind wing two long 
strong hairs (see f, Fig. 8), the very counterpart of the generalized 
49 : 
a 
