30 ANNALS OF SCOTTISH NATURAL HISTORY 



are obsolete or entirely absent, but the outer branches are 

 three -jointed. Inner branches of the fourth pair (usually) 

 two-jointed and the outer branches three-jointed. Fifth pair 

 foliaceous, small, two -branched (basal joints sometimes 

 coalescent and forming a broad lamelliform plate ; the fifth 

 pair in the male are smaller than those of the female. One 

 ovisac, containing a few large ova). 



LEPTOPSYLLUS ROBERTSONI, Sp. nov. (Plate II. Figs. 1-14). 



Description. Female. Length -63 mm. (^ of an inch). 

 Body elongate and very slender. Anterior antennae moder- 

 ately stout, shorter than the first cephalothoracic segment, 

 seven-jointed : the fifth joint is shorter than any of the others, 

 as shown by the formula : 



Proportional length of joints 22 13 10 7 5 8 9 

 Number of the joints i 2 34567 



Posterior antennae nearly as in Leptopsyllus typicus, T. Scott. 

 Mouth organs also nearly as in that species, except that the 

 mandible-palp is two-branched ; the distal branch, which is 

 slender and elongate, has the end joint equal to about two- 

 thirds the length of the first joint ; the proximal one-jointed 

 branch is nearly as long as the first joint of the distal 

 branch. The first pair of swimming feet are similar to 

 those of Leptopsyllns typicus, but the inner branches are rather 

 longer than the outer, and there is a fascicle of moderately 

 long setae on the inner margin of the second basal joint (Fig. 

 9). In the second and third pairs the outer branches are 

 somewhat similar to those of Leptopsyllus typicus ; the inner 

 branches, which are rudimentary, are two-jointed, the end- 

 joint being very small (Fig. 10). The fourth pair are similar 

 to those of Leptopsyllus typicus. The basal joints of the fifth 

 pair are coalescent, forming a broad lamelliform plate, the 

 end of which is broadly truncate and slightly concave, the 

 obtuse angles being each furnished with two small setae, and 

 on each side near the base of the joints the outer margin is 

 produced into a broadly rounded lobe terminating in two 

 setae ; the length of the basal joints is equal to about two- 



