1876.] How Cockroaches and Earwigs fold their Wings. 523 
wholly concealed by the tegmina. When this triangle has en- 
larged still more, as in the East Indian Prosoplecta coccinella 
(Figure 30), the nervules on either side of it have been forced, 
Fie. 80. 
as it were, to curve upward or downward to give it room ; those 
below the triangle have undergone a still more remarkable mod- 
ification to which we shall again allude. In further steps this 
triangle expands still more (Figure 31, Plectoptera porcellana of 
Fie. 31. 
Cuba), throwing the veins on either side of it farther and farther 
back, until they fall into a single straight line at right angles to 
their former direction, one being turned upward, the other down- 
ward ; and as this line marks the crease where in Hetobia lap- 
_ Ponica the triangle was folded back upon the top of tHe wing, so 
_ how the wing, having first been folded longitudinally throughout 
Its entire length (the hinder portion lying beneath the upper), 
has its tip folded over, not far beyond the middle, upon the upper 
Surface of the wing. 
