30 Annals Entomological Society of America [Vol. XV, 



structures with the parameres are (1) their origin as evaginations 

 of the wall of the spermatophore sac (cf. Centhophiliis), and (2) 

 their muscular connections, which are comparable to those of 

 other groups of Orthoptera. 



In Nemobiiis fasciatus DeGeer the male genitalia are sur- 

 prisingly unlike those of Grylhis, considering how nearly related 

 the genera are in other respects (PI. V, Figs. 42, 43). The 

 pseudosternite is partially retracted and adherent to the over- 

 lying integument. It has no median process, but has two 

 pairs of lateral ones, of which the upper may represent the 

 median process of Gryllus, the lower ones the lateral processes 

 of that genus. Between the lower pair is another pair of more 

 flexible processes, evidently the homologues of the ectopara- 

 meres of Gryllus. The pseudosternite extends down on each 

 side at base, but is not narrowed into distinct rami. 



The remarkable feature of this form, however, is the sperm- 

 atophore sac, which is really not a sac at all, as it does not 

 become invaginated, but is merely longitudinally sulcate. At 

 the distal end the plate which lines the "sac" is greatly con- 

 tracted and has a very narrow channel, but farther proximad 

 it is considerably expanded and much more broadly sulcate. 

 The endoparameres take the form of long slender rods, which 

 are divergent towards their free ends. They have the same 

 origin as in Gryllus, viz., as evaginations of the wall of the 

 spermatophore sac. As a result of the form of the spermato- 

 phore sac the ventral lobes are far forw^ard and completely 

 hidden, the entire spermatophore sac lying behind them. 

 They are also relatively smaller and less distinctly separated 

 from one another than in Gryllus assimilis. 



In Nemohius carolinus Scudd. the genitalia are very similar 

 to those of N. fasciatus, but in the European N. sylvestris Fab., 

 according to Lespes ('55 b) there is some approach to Gryllus in 

 the longitudinal curvature or slight invagination of the spermato- 

 phore sac. 



In the tree-cricket Oecanthus nigricornis Walk, the genitalia 

 are like those of Gryllus in most respects, (PI. V, Figs. 44-46), 

 differing chiefly in the following features: The pseudosternite 

 has a pair of prominent internal projections just mesad of the 

 bases of the endapophyses. These are only slightly 

 indicated in Gryllus. The median prong is represented by a 

 pair of processes close together, while the lateral prongs are 



