62 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



5. Tergal muscles of the anterior intervalvida (fig. 17 E, H). — A 

 slender muscle on each side arising on anterior margin of lateral part 

 of ninth tergum ; the two converging ventrally to insertions medially 

 on anterior intervalvula (aiv). 



6. Anterior tergal muscles of second valvifers (fig. 17 E, G, H). — 

 A pair of large vertical muscles, arising on anterior lateral apodemes 

 of ninth tergum, internal to 5 ; insertions ventral on anterior processes 

 (inferior apophyses) of second valvifers (G, H). 



7. Posterior tergal muscles of second valvifers (fig. 17 E, G, H). — 

 A pair of large, flat, horizontal muscles ; each arising anteriorly on 

 anterior margin of ninth tergum (H), external to 6 (E) ; inserted 

 posteriorly on posterior dorsal apodeme (superior apophysis) of sec- 

 ond valvifer (E, G, H, i). 



8. Tergal muscles of posterior intervalvula (fig. 17 E, H). — A pair 

 of relatively slender muscles, arising on lateral parts of ninth tergum 

 (E) above 5 and external to upper ends of 6; extend ventrally and 

 posteriorly, ectad of 7, to insertions in membranes laterad of posterior 

 intervalvula (E, H, piv), with a few fibers attached on the latter. 



The next two pairs of muscles have a ventral position and connect 

 the valvifers with the posterior intervalvula, but their homology with 

 muscles of the pregenital segments is not clear. They are described 

 by Ford (1923) as primary and secondary " outer sternal muscles" 

 of the ninth segment. An " inner sternal muscle "of the ninth seg- 

 ment, she says, extends from the first valvifer to the paraproct, but 

 the writer did not observe this muscle in the female of Gryllus, which, 

 according to Du Porte (1920), occurs in the male only. 



9. Intervalvidar muscles of the first valvifers (fig. 17E, H). — A 

 pair of short, thick, cylindrical muscles arising on sides of median 

 apodeme (^) of posterior intervalvula {piv) ; extending laterally and 

 a little forward to posterior internal apodemes of first valvifers (H, /). 



10. Intervalvular muscles of second valvifers (fig. 17E, H). — 

 Origins medially on apodeme of posterior intervalvula {k), ventral 

 to p; diverge anteriorly to insertions on anterior ends of second 

 valvifers. 



Muscles pertaining to the rudimentary second, or inner, valvulae the 

 writer did not find in Gryllus, but Ford (1923) describes a pair of 

 such muscles having their origins on the anterior intervalvula and their 

 insertions in the tips of inner valvulae. In Scuddcria the well-devel- 

 oped muscles of the inner valvulae have their origins on the inner 

 faces of the second valvifers. 



The mechanism of the ovipositor. — The eggs of Gryllus are laid 

 in the ground. Before inserting the ovipositor the female often clears 



