25G 



MR. B. F. CUMMINGS ON 



same type as that described for P. brachyrrhynchus. Tt differs, 

 however, in details. 



The basal plate is small. Anteriorly it is very narrow, being- 

 little more than a rod or band. Lower down, towards the 

 paramera, it broadens rapidly, and its two lower lateral angles 

 are produced so that the whole plate somewhat resembles an 

 inverted catapult as tisecl by schoolboys. 



The paramera articulate Avith the produced angles of the basal 

 plate. Beyond the point of articulation the base of the parameron 

 projects into the intraparameral space. Towards the extremity 

 each parameron broadens out and meets the other clistally beneath 

 the mesosome, for which they form a basin-shaped cavity. 



The penis is a curved, pointed, narrow rod with a forked base. 

 As in P. brachyrrhynchus, the forked basal part may be a separate 

 piece. The limbs of the fork enclose the lower part of the rest 

 of the mesosome, as shown in the figure. 



Text-figure 7. 



"Polyplax spinulosa. 



Male copulatory apparatus: — a. Dorsal view. b. 

 X 350. 



Side 



BF. Basal plate. Par. Parameron. P. Penis (f, finger, and t, thumb). 

 Ma. Mesosome (anterior part). Mp. Mesosome (posterior part). 



Comparison with the Male Copulatory Apparatus of Polyplax 

 spinulosa {Burmeister). (Text-fig. 7.) — The remarkable copu- 

 latoiy apparatus of this common species of Polyplax from Rats 

 has hitherto remained unnoticed save for a summary description 

 by Piaget (2, p. 636), which is difficult to follow and is accom- 

 panied by an inaccurate figure (pi. lii. fig. 2 a). 



