1922] Walker: Structtire of Orthopteroid Insects 19 



margin of many forms, this feature being particularly noticeable 

 in young nymphs and sometimes, as in species of Ceuthophilus, 

 secondary subdivisions are present. Styli are present in the 

 majority of genera, though frequently absent, as in many of 

 the Rhaphidophorinse, which in this respect, and also in the more 

 convex and upturned ninth sternum, the unmodified cerci and 

 the structure of the genitalia, approach the Grylloidea. The 

 cerci are generally short, unsegmented and modified to serve as 

 claspers in copulation, but in the Rhaphidophorince, with few 

 exceptions, they do not function as such, being like those of the 

 female, comparatively long, flexible and tapering, and covered 

 with sensory hairs. In some species of this family, such as 

 Pristoceuthophilus cercalis Caud., the cerci have a few small 

 terminal segments, but this character, though an interesting 

 exception to the general rule in the Orthoptera, is probably 

 an atavistic one. A small cereal basipodite is sometimes, but 

 not always, present. In the large membranous area between 

 the paraprocts and the ninth sternum is the penis, which is 

 described below. 



In Cyphoderris monstrosa Uhl., (PI. IV, Figs. 35, 36) an 

 aberrant species, usually placed in the Stenopelmatinae, a most 

 remarkable modification of the genital structures is present. 

 The ninth sternum is bent vertically upwards and closely 

 applied to the end of the abdomen, which it covers below the 

 paraprocts. Into the narrow pocket thus formed opens the 

 genital passage, whose folded, membranous lips are the only 

 representative of the penis, there being no chitinized parts. 

 There is, however, in place of the titillators or parameres, a 

 large process arising from the 9th sternum. It projects some- 

 what backward and is then sharply bent downward, terminating 

 below in a pair of divergent spines. The dorsal surface also 

 bears minute spinules. In a nearly full-grown male nymph 

 of this species there is no indication of this structure, and the 

 sternum, though bent up, is less closely applied to the body. 

 In both adult and nymph there is a pair of stout, flattened 

 styli, which, from their position, are at first sight, somewhat 

 suggestive of titillators. 



Grylloidea. In the crickets the abdominal segments are 

 similar to those of the Tettigonoidea, except that the ninth 

 sternum is smaller, more narrowed caudally, and envelopes the 

 genitalia more closely, there being a smaller outlet for the 



