258 MR. B. F. CUMMINGS ON" 



{larynx of Enderlein) and fulturse (5). No attempt is here made 

 to describe the mouth-trophi, but attention is drawn to two 

 structures lying together just behind the pharynx and above the 

 needle-like tropin, strongly suggesting mandibles. In the figure 

 tbey are labelled mandibles, and the chitinous band which runs 

 backward from each is indicated as a tendon. Mandibles, of 

 course, in blood-sucking Anoplura cannot be functional, but their 

 presence as vestiges is to be expected if the Anoplura are in 

 truth descended from the mandibulate Mallophaga. Enderlein (4) 

 regards as mandibles certain pieces in the head of Hcematopinus 

 suis. Mjoberg (3) figures and describes mandibles in Arctophthirus 

 tricked Boh. The latter are extremely suggestive in form, and 

 much resemble the mandibles here figured. 



Spermatheca. (Text-fig. 9.) — Mjoberg (3, p. 254) finds a 

 spermatheca present in Linognathus angulatus Piag. and in 

 Acanthopinus sciurinus Mjob., in both of which it consists of 

 the same form, i. e., " Aus einern fast kreisrundem Gebilde das 

 beiden Ubergang in den sehr schmalen Ausfiihrungsgang mit 

 einer gerundeten Chitinscheibe versehen ist, von deren Mitte der 

 Ausfiihrungsgang seinem Ursprung nimmt." Landois (6, p. 14) 

 described the spermatheca of Phthirus inguinalis and remarked 

 (7, p. 32) upon its absence in Pediculus vestimenti. Patton & 

 Oragg (5, p. 560) single this out as a fact of some interest in view 

 of the length of copulation in the louse and the large size of the 

 seminal vesicles in the male. Landois explains the difference in 

 Phthirus and P. vestimenti in this matter by reference to the 

 habits of the two insects — Phthirus is sedentary and therefore 

 rarely meets with its kind ; the Pediculus is active, and coitus is, 

 therefore, frequent. 



Whatever be the explanation, the absence of the spermatheca 

 in P. vestimenti is a confirmed fact, and it becomes a matter for 

 further research to enquire from what other genera in both 

 Anoplura and Mallophaga this receptacle may be absent. It 

 probably occurs in a great many Mallophaga in which its chitinous 

 " Scheibe " can frequently be seen at the end of the abdomen 

 through the integument of specimens passed through caustic 

 potash. Mjoberg figures it from Nirtnus lineolatus 1ST., and 

 reports it as probably present in many Ischnocera,. In the 

 Amblycera he sought for it in vain. It may, however, exist 

 unchitinised in these forms, though the club-shaped organ found 

 in Menopon titan by Grosse, who regarded it as a s]3ermatheca, 

 is reported by Snodgrass (8) to be non-existent. 



In the two species of Polyplax here described, a spermatheca 

 is present, and its chitinous parts can be detected in specimens 

 passed through potash. Text-fig. 9 shows the part in P. oxyr- 

 rhynchus. In general form it resembles the figure of the 

 spermatheca of Phthirus inguinalis. Nothing comparable to 

 the " Chitinscheibe " or disc of Mjoberg was observed; in some 

 specimens, passed through caustic potash, the chitinous part of 

 the duct B (the funnel) was telescoped backwards into the 



