stough: the hackberry psylla, 15^ 



Extending ventrad, with its dorsal edges articulating with 

 the lower side of each of the above-mentioned lobed plates, is 

 a chitinized band or loop (figs. 6 and 7, extending down- 

 ward almost to touch the inner surface of the subgenital plate. 

 Between the arms of this loop the proximal portion of the 

 copulatory organ swing, almost entirely concealed within the 

 subgenital plate when the genital segment is telescoped into 

 the next segment cephalad and the supra-anal plate is forced 

 caudad. At emergence, however, the genital organs are ex- 

 tended and not telescoped, and at time of copulation the copula- 

 tory organ is protruded from the cavity of the subgenital plate. 



Extending ventrad from the lateral plates at the base of the 

 supra-anal plate is the chitinized couplatory organ or extremity 

 of and sheath for the penis — "the sedeagus" of some writers. 

 This organ (figs. 6 and 7, co, and 35-1), soon after it leaves 

 the base of the supra-anal plate, forms a sharp bend, reversing 

 its direction to dorsad. After reaching a position about oppo- 

 site the middle of the supra-anal plate there occurs a conspicu- 

 ous swelling, and beyond that a joint or geniculation {30- 

 Q, g). The proximal portion of the second segment of the 

 organ is also swollen. This segment in normal position drops 

 ventrad. The distal end bends caudad and is swollen greatly, 

 becoming club-shaped (fig. 6, c), convex cephalad, and con- 

 cave caudad, this segment having a vertical orientation. The 

 convex, cephalic face of the club is gouged out to form a deep 

 longitudinal groove running from base to tip. 



The proximal portion of the first segment of the copulatory 

 organ is not tubular, but slitted on its convex surface, and 

 through this slit the penis enters the sheath, p. The concave 

 surface of this portion is coarsely notched or corrugated trans- 

 versely for some distance beyond the bend. The remainder of 

 the organ is tubular, the canal running through the inner half 

 of the sheath — that is, through the cephalic half of the first 

 segment and through the caudal half of the second segment. 

 This canal runs into the center of the club, makes a sharp turn, 

 and, proceeding back upon itself, curves to the convex side of 

 the club, where it issues at the base of the club in the bottom of 

 the groove above mentioned. 



The copulatory organ is more strongly chitinized at its distal 

 end than it is in the curved portion of the proximal segment, 

 and along its outer surface, than on its inner. The first seg- 

 ment measures (from base to geniculation, the distance along 



