158 KANSAS UNIVERSITY SCIENCE BULLETIN. 



of the cephalic pair, sc 1, are pointed, with convex inner sur- 

 faces. Their tips have a connection with the lateral plates 

 (figs. 1, 2 and 3, pi), the latter probably serving to spread 

 these sclerites apart. The caudal pair, sc 2, reach almost to 

 the base of the sheath surrounding the stylet tips, are rectan- 

 gular in shape, with rounded ends, and with their inner sur- 

 faces corrugated, the corrugations corresponding to the 

 striations on the surfaces of the lateral tongues of the ovi- 

 positor. 



The sheath already mentioned (figs. 1, 2 and 3, sh) is 

 slitted on its dorsal surface from near its cephalic edge to the 

 apex of the ovipositor, to allow of the spreading of the stylets 

 and the passage of the egg during oviposition. The cephalic 

 portion of its dorsal face carries the small, valve-like, ventrad- 

 projecting process (fig. 1, v). 



Fig. 1, pi. 26, shows a cross section about midway through 

 the organ. In this the fleshy structures that were destroyed in 

 boiling in caustic potash can be made out. The grooved and 

 toothed valves, uv and Iv, are seen fitted together, and the 

 chitinized portion, x, which is grooved and forms the sides of 

 the oviduct. Above the oviduct, and forming its roof, is the 

 structure, y, whose ventral surface is covered with minute, 

 soft, hair-like outgrowths, and whose dorsal portion is chitin- 

 ized. The part marked z probably represents the lateral 

 plates, Ipt, of 30-1, 2 and 3. The duct of the cement (?) 

 gland is seen at cmgd in this figure and appears in all sec- 

 tions cephalad of this, and in those caudad up to the point 

 where it turns ventrad and enters the oviduct. The entire 

 course of this duct was best seen in longitudinal-vertical sec- 

 tions, but could be traced well in longitudinal-horizontal sec- 

 tions, where its union with the oviduct was plainly seen, and 

 in the next succeeding sections ventrad the oviduct was laid 

 bare. The cement (?) gland itself, a small sac, was found 

 somewhat cephalad of the base of the ovipositor in most of 

 my dissections. Figure 6, plate XXXI, is of a cross section 

 near the base of the ovipositor sheath. Here the shape of the 

 supra-anal and subgenital plates can be seen, also the position 

 of the oviduct. The lateral tongues or sting-palpi are also 

 represented. 



I have pointed out the structure of these parts and shall 

 now give my theories as to the homologies. The typical struc- 



