526 How Cockroaches and Earwigs fold their Wings. [ September, 7 
the hypothesis of any unity of type in the wing structure of 
insects, 
But these later developments in the modification of the veins 
themselves have no bearing upon the structure of the wings of 
earwigs, and have only been introduced for their own interest and 
to complete the account we have given of duplicature in the 
wings of cockroaches. We may, however, keep the last state- 
ment before us when we recall the fact that the wings of all ear- 
wigs (so far as I have been able to determine after an examina- 
tion of many types otherwise diverse) are identical in their gen- 
eral structure and wholly different from those of any other 
insects, having been extraordinarily modified to serve a special 
purpose. 
In these insects the fore wings (tegmina) are always small 
and generally but little longer than broad, although earwigs are 
invariably slender, and the tegmina, to cover the abdomen, would 
need be very long. The wings, when folded, generally extend 
a little beyond the tegmina, and the parts which protrude are 
coriaceous and wholly devoid of veins ; being moreover frequently 
ornamented with a colored spot or stripe, and thus further re- 
sembling the tegmina, they might be taken for a second pair of 
tegmina precisely like the first, or differing only in a slightly 
increased length ; even if the tegmina are removed the deception 
remains, for the parts of the wings then exposed are coriaceous 
to the base. These wings, however, are quite as ample as those 
of other Orthoptera of equal size ; but, by a complicated system 
of duplicature, accomplished by the mere elasticity of the parts, 
they are in a few seconds packed snugly beneath the pad-like 
tegmina, out of danger of abrasion or rupture, as the insect seeks 
the hidden recesses and crevices where it passes the larger part 
of its existence. : , 
The most extraordinary thing about the structure of the wings 
is the immense extent of the anal area; not only does this reach 
from base to apex of the wing, as in the extreme type of cock- 
roaches, but the entire wing, excepting only a portion about 
equalling the area of the tegmina, is made up of this field ; the 
portion which does not belong to it is almost entirely coriaceous, 
so that nearly all the nervules of the wing belong to the ani 
vein. In the hind wings of Orthoptera in general, this anal vem 
may be roughly described as consisting of a basal are to WY” 
the bases of the various rays are attached one beneath another ; 
or, rather, the enlarged bases of these rays, lying one be 
