stough: the hackberry psylla. 167 



position about opposite and above the last spiracle, well into 

 the dorsal portion of the last abdominal segment. Its position 

 relative to the two plates is shown in figure 1 B, plate XXVI. 



Seven longitudinal rods or valves are to be found running 

 throughout the organ. Six of these are paired, two pairs form- 

 ing the lateral edges of the ventral face of the organ, and a 

 third pair lateral and well towards the dorsal face ; the seventh 

 and unpaired rod is dorsal and median. 



Each upper and each lower valve of the two ventral pairs are 

 very closely connected, being held together throughout their 

 entire length by means of a tongue on the upper fitting into a 

 groove in the lower, which may be seen in the cross section in 

 26-1 A, tg. The tips of these valves are very sharp and 

 finely pointed, and come together at their tips, where they are 

 enclosed in a sheath. The cephalic ends of each ventral and 

 inner stylet is connected with a more or less crescent-shaped 

 sclerite (26-1, blv). The cephalic end of each ventral and 

 outer stylet connects with a sclerite (fig. 1, buv) which runs 

 dorsad and caudad. When this reaches about the dorsal face 

 of the ovipositor it turns caudad and becomes a thin rod, Ir, 

 and at about the middle of the ovipositor becomes compressed 

 laterally to form a wide, thin plate, which gradually loses its 

 chitinization, and is lost in the fleshy tongues on each side of 

 the ovipositor sheath (figs. 1, 2 and 3, stp). 



Situated medially and a little dorsad of the above-mentioned 

 rods is a rather thick, cylindrical rod bent at its cephalic end 

 slightly dorsad, then ventrad (fig. 1, mr). This rod does not 

 project quite as far cephalad as the stylets below. It is greatly 

 swollen at its caudal extremity, with a square end, and its ven- 

 tral portion is continued into a slender process, in shape much 

 like a human femur, procv. This last-named process works 

 against a ventrad-projecting outgrowth of the sheath sur- 

 rounding the stylet tips, which serves to close the oviduct (fig. 

 1, v). Lying above this slender sclerite are two pairs of chit- 

 inized sclerites (figs. 1 2 and 3, sc 1 and sc 2), which are 

 connected with and probably serve to bring about lateral ad- 

 justment of the lateral tongues above mentioned. Viewed 

 laterally, these sclerites appear as one pair (fig. 1), but when 

 viewed from above, and pressure was applied to the dissec- 

 tion so as to spread the sides apart, they were seen as two 

 distinct pairs of sclerites, Viewed in this njanner, th^ sclerite^ 



