542 On Aquatic Carnivorous Coleoj^tera or Dytiscidai. 



prosternal process, and the breadth of the jjrothoracic lateral margui. All the 

 variations I have observed connect more or less with what I have called the first 

 form. 



Outside the limits of Australia there occur additional variations, which have no 

 other claim than their geographical separation to be considered distinct species, and 

 which I therefore cannot accept as such. Thus in Tasmania there is found a form 

 differing by the straighter sides of its thorax from the Australian central form, and 

 it has the yellow lateral stripe of the elytra extending without interruption to the 

 humeral argle of the elytra. I have seen but one individual of it, the only 

 Tasmanian specimen of the species that has come before me. 



In the Philippine Islands, the Agabus semperi, Wehncke, departs but little 

 from the first Australian form, but the spots on the head and front angles of the 

 thorax are reduced in size, as is also the lateral band of the elytra, while on the 

 other hand the two adjacent spots on the elytra have become very conspicuous ; 

 the surface is very shining, and the verj^ fine reticulation of the elytra is even more 

 indistinct than in the shining first Australian form. 



In Java occurs a form similar to the first Australian form, but with the upper 

 surface nearly entirely black, and with the hind legs more slender ; on 

 examination the anterior angles of the thorax are decidedly reddish, and the 

 lateral band and adjacent spot on the elytra may be detected ; the upper surface is 

 very shining, and the meshes formed by the very fine scratches of the elytra are 

 rather larger, and have no trace of accompanying minute punctures such as may be 

 found in the Australian form. 



Another variety resembles in size, form and sculpture, the individuals from Java 

 and the PhilijDjiine Islands, but has the yellow marks on the elytra formed into five 

 very definite spots on each ; I have seen individuals agreeing in this respect but 

 differing {ji'sr -seas to minor details, from the Philippine Islands, Ternate, and New 

 Guinea. 



764. Platynectes daemeli, n. sp. — Ovalis, latus, subdepressus, nitidus, niger, 

 antennis pedibusque rufis ; crebre subtiliter reticulatus ; prothorace brevi, cum elytris 

 omnino continue, angulis posterioribus peracutis, ad elytia arete applicatis ; prosterni 

 processu lato, fere piano, apice peracuto ; abdomine segmento ultimo ventrali in 

 utroque sexu fere Isevigato. Long. 7, lat. 4 m.m. 



The male differs from the female, only by a slight incrassation of the front and 

 middle tarsi, and by their basal joints being furnished beneath with short glandular 

 hairs. 



Though very closely approximated by the flatter and broader varieties of Dytiscus 

 decempunctatus, it seems to be really distinct ; the form is yet broader, but is more 

 acuminate behind, the variegation of the surface with yellow is nearly absent, the 

 antennae are always shorter, and the apical ventral segment quite free from strigose 



