416 



Transactions of the Society. 



can easily be done, though it takes a certain knack to break off 

 only the required parts, which is desirable, as if other segments 



come off, the repairing is ex- 

 tremely difficult. The detach- sd 

 portion should then be boiled 

 gently in caustic potash, the 

 genitals withdrawn and washed, 

 and the two segments placed 

 back in position and cemented. 

 It is well to label such an in- 

 dividual, as if the repairing is 

 well done, one may attempt to 

 repeat the process at a later date 

 upon an already castrated speci- 

 men. These old specimens are 

 never so satisfactery as fresh or 

 as spii it-preserved ones, since 

 the delicate structures within 

 the preputial sacs are always 

 obscured ; but at all events, the 

 outlines of the metaparameres 

 can be seen clearly, and this is 

 a very important point. 



The male reproductive ap- 

 paratus of earwigs consists of a 

 pair of chitinous segments, the 

 parameres, which are attached 

 to a fibrous muscular base, the 

 first segment, or proparameres, 

 usually simple long and narrow 

 plates, strongly chitinized in the 

 external margin only ; the api- 

 cal segments or metaparameres 

 offer an extraordinary diversity 

 of size and shape, and are of 

 great systematic value. Some- 

 times there is a small acces- 

 sory lobe, or epimerit, at the 

 apex of the metaparameres. 



The metaparameres are at- 

 tached by a distinct hinge to the 

 parameres in most Protodermap- 

 tera. but are almost fused into 

 one in the Echinosomatimv and 



Fig. 55. — Protodermapterous Type. 



a. Metaparameres. 



B. Proparameres. c. Hiuge. 



d. Preputial sac in repose. 



e. Ditto, in erection. 



f. Virga, with spiral structure (Allo- 



stethine type.) 

 G. Basal vesicle of virga (Echinoso- 



matine type). 

 H. Ejaculatory ducts (indistinct). 

 I. Simple form of virga. 

 J. Projecting whip-like end of virga 

 in erection. 

 Pads of denticulations. 

 Chitinous thickenings. 

 Strongly chitinized external 



margin of proparameres. 

 Midrib of metaparameres (Psalid 

 type). 

 0. Internal tooth of metaparameres. 



K. 

 L. 



M. 



N. 



in the Eudermaptera, where the 

 proparameres are degenerate. The former act as grips, for locking 

 the organs to the female in copula. Attached to the parameres 



