REVISION OF ELEODIINI BLAISDELL. 19 



act as guides to and steady the edeagophore under certain condi- 

 tions: in the female the interval between these triangular sclerites 

 is continuously membranous and feebly chitinized, so that movement 

 betAveen the lateral moieties is impossible, and the internal basal 

 processes are connate. (Plate 7, fig. 3<^/.) The external basal proc- 

 esses articulate with the tergite of the same segment as described 

 above. 



The eighth segment is membranous in both sexes. 



The tenth segment is aborted in the female as usual, the tergite 

 fusing with the ninth tergite to constitute the supra-anal plate. 

 (Plate 7, fig. -iq.) In the male the tergite of the tenth segment 

 forms the supra-anal i:)late; the subanal or sternal wall is mem- 

 branous in both sexes, possibly somewhat chitinous in the male. 



The supra-anal plate is more strongly chitinous laterally and more 

 membranous at middle (Plate 7. figs, '^q and 4^) and is in relation 

 laterally with the paranal plates or sclerites. 



In the male these paranal sclerites are much smaller and less tri- 

 angular than in the female, and articulate with a chitinous rod 

 on each side ; these rods converge anteriorly so as to form a Y-shaped 

 support and a mechanism for the extension and retraction of the 

 edeagophore; they are wholly internal and give attachment to muscles 

 and ligaments. 



The paranal plates in the female are irregularly siibquadrate, 

 occupying the lateral wall below the supra-anal plate. Each paranal 

 sclerite may be said to present for examination four borders: a 

 superior, posterior, inferior, and an anterior: four angles: the antero- 

 inferior and postero-inferior being the most important. 



The superior horde)' is connected to the sides of the supra-anal 

 plate by membrane, apparently forming an articulation at its antero- 

 superior angle with the antero-external angle of the anal plate; the 

 postenor harder is connected by articulating membrane to the basal 

 margin of the ventral plate or valve: the Inferior border gives attach- 

 ment to the membrane of the ventral wall, and the anterior horder 

 giving attachment to the membi'ane of the eighth segment. 



The antero- ventral angle is short and apparently gives attach- 

 ment to muscles and ligaments which steady the plate against the 

 valve. 



The ijostero- ventral angle is produced into the process of the 

 paranal plate to articulate with the strongly chitinized basal margin 

 of the ventro-lateral plate of the valve, of the same side and upon 

 which the valve plays during abduction and adduction. (Plate 3, 

 fig. 4r/.) 



The above description of the retractile segments has been founded 

 upon those of Eleodes cordata^ as illustrated in Plate 7. The seg- 



