1883.] 39 



consequently, the femur forms with the trochanter almost a right angle. Viewed 

 from the inner side, the basal half of the femur is somewhat parallel -sided, with a 

 square base ; on the under-side it tapers from the middle to the apex. Under-side 

 armed with a few hair-like soines, as is the trochanter. Tibia slender, as long as the 

 femur, nearly equally thick throughout, the apex somewhat dilated, the under-side 

 produced and forming a short straight process. Tarsus less than half as long as 

 the tibia, 2-jointed ; 1st joint about one-third the length of the 2nd, slightly in- 

 crassate upwards ; 2nd slightly incrassate upwards, with an excaTation on the under- 

 side before the tip, in which the claws are probably inserted. 



Middle-legs : acetabula situated at the hind angles of the mesothorax, large, 

 cylindrical, with a long suture on the under outer side, opening circular, looking 

 backwards. Coxa cylindrical, about as long as broad, apex hollowed, with a semi- 

 circular emargination on the outer under-side. Trochanter with a ball-like base, 

 ""^her narrow neck and triangular apex to the outer upper face of which the femur 

 articulates. Femur very long and slender, nearly equally thick throughout, but a 

 little incrassate at base and apex, armed with a few hair-like spines, the apex with 

 two teeth, between which the tibia is inserted. Tibia about one-third the length of 

 the femur, slightly curved, narrowing from the base to the middle, the apex rather 

 flatly dilated on the inner side. Tarsus two-thirds the length of the tibia, 2-jointed ; 

 1st joint tapering from just above the base to the apex, rather flat, furrowed on the 

 upper side from base to apex ; 2nd joint about one-third the length of 1st, narrower, 

 equally broad throughout, slightly flattened, and with a slight furrow, especially 

 near the base on the upper-side, slightly excavated on tjie inner side before the tip. 



Hind-legs : acetabula occupying the hind angles of the metathorax, consequently 

 the hind-legs are inserted above the middle-legs ; similar to the middle acetabula, 

 but longer. Coxa a little longer than middle coxa. Trochanter, like middle tro- 

 chanter, reaching backwards nearly as far as the apex of the abdomen. Femur 

 rather longer and more slender than the middle femur. Tibia shorter than the 

 middle tibia, about one-fifth the length of the abdomen, cylindrical, tapering from 

 base to apex. Tarsus about one-third the length of the tibia, 2-jointed, joints 

 cylindrical, 2nd about one-half the length of the 1st, slightly excavated on the 

 inner side before the tip. 



In many respects, Platygerris resembles Salohates, and still more 

 Salohatodes (a new genus, of which the type is Halolates lituratus, 

 Stal), but in the shape of the body, the structure of the genital seg- 

 ments, the form of the anterior trochanters and femora, and of the 

 middle tibia and tarsus, as well as in other characters, it diverges very 

 considerably. To Hydrolates the affinity is much less strong, though 

 part of the structure is suggestive of that genus. 



I may take this opportunity of mentioning that I think of 

 attempting to monograph the species of Hemiptera that dwell on the 

 surface of water (families Hydrohatina, Hydrometrina, &c.), and will 

 be very glad of the loan of specimens. 



Perth : May 22»d, 1883. 



