BAUMGARTNER: COPULATION IN GRYLLID^. 333 



of the wall of the vesicle as shown in figures 1 to 3. The dark 

 stain here shows the outer limits of the inner lining, and the 

 cavity is on the inside, as shown in the outline drawings. The 

 cavity is easily visible in the preparations but the photos do 

 not bring it out. At the posterior end the cavity is flattened 

 and at the other end it gradually tapers down to the size of the 

 thread; so that the shape of the opening is much like a flat- 

 bottomed flask. In this cavity all the sperm have their heads 

 directed toward the openings into the thread and their tails 

 toward the papilla. Figure 11 is a small group of sperm 

 photographed from a section of a spermatophore. In passing 

 out of the thread the sperm manifested some movement of 

 their own, but were not very active. Several may pass out 

 together but only two or three heads have room side by side. 

 The sperm are larger than Lespes thought, as can be seen by 

 comparing with my earher published measurements (1). 



The Spermatophore- forming Organ. 



Since many of our textbooks on entomology — see Packard 

 {18) and Henneguy {10) — still cite Gryllus as showing one of 

 the simpler conditions for the excreting ducts of the testes 

 among the insects, I shall give a more detailed account of the 

 male generative organs, their ducts and the accessory glands, 

 than I should otherwise do. 



The first description of these parts was given by Dufour (5) , 

 in Gi^llus campestiis, then by Lespes {11), in G. domesticus, 

 later by Berlese {4), again in G. campestris, and then by Fen- 

 ard {6), in both of the above species. 



The testes lie on either side of the abdomen above the ali- 

 mentary canal and extend from the second to the sixth or 

 seventh segments. The shape is much like that of an elongated 

 strawberry. On the outside is a thin membrane which encloses 

 the hundreds of straight or slightly curved tubules which 

 make up the organ (figs. 6 and 7). Their blind ends are 

 nearly all directed more toward the posterior end of the body of 

 the animal. At the center of the testes is a large tube, or 

 rather an irregular sinus, which receives the openings of the 

 hundreds of tubules (fig. 8). The small vas deferens leaves 

 this sinus on the anterior ventral side and comes to the ventral 

 side of the testes a little back of the middle. It passes back- 

 ward over the tubules, and leaving them at the outer posterior 

 edge passes back along the body wall muscles till it reaches the 



