WALKING-STICKS AND WALKING-LEAVES. 43 



We have seen that the tegmina, or elytra, as the fore 

 wings are called, are usually of small size or absent, and 

 when present are attached at the posterior part of the 

 mesothorax. Most often they have the form of scales, 

 and cover merely the base of the wings, and are coria- 

 ceous, generally raised in the form of a tubercle, and 

 opaque. The lower, or true wings, on the other hand, 

 may be very large, extending in repose, in a limited 

 number of species however, as far as the extremity of 

 the abdomen, without exceeding it, and are attached to 

 the anterior part of the metathorax. This attainment of 

 a greater development of the wings than the elytra is 

 opposed to what obtains in the other families. When 

 one of the pairs of appendages are wanting, it is on the 

 elytra the complete atrophy falls. In the genus Aschi- 

 pasma, for example, one finds the wings fully developed, 

 but elytra none ; and in Phantasis we discover vestiges 

 of hind wings, but of elytra similarly no trace whatever. 

 True, an exception occurs among Phyllium females, 

 where the upper wings become developed and the lower 

 ones dwindle away ; but this is for a special purpose, 

 which will be dealt with later on. 



In the absence of wing-covers of a size adequate to 

 protect the normal wings in repose, it is essential that 

 provision be made for their defence. This is effected by 

 the outer margin of the hind wing itself, which is greatly 

 thickened, serving as a flat plate or sheath to the greater 



