728 On Aquatic Carivorous Coleoptera or Dytiscide. 
other, the female sexual sculpture is very largely developed, while the patches of 
sexual pubescence on the intermediate tarsi of the male are largely developed as in 
the second form. 
The fourth or African form is usually large and very elongate, with the yellow 
cincture largely developed: the females never have the least trace of sexual sculp- 
ture, and the patches of sexual pubescence on the intermediate tarsi of the male 
are moderately developed, intermediate in size between those of the first and 
second forms, but with the hairs usually rather longer than in either. 
The characters are however variable, and no definite limits can be assigned to 
the four forms as will be seen from the following more detailed sketch of the local 
variations. 
Japan.—Eight individuals from three sources are before me from this locality : 
the smallest individual (a male) is 24 m.m. long, 12} m.m. broad, 73 m.m. high ; 
the largest (a female).28 m.m. long, 143 broad, 83 m.m, high : the yellow mark on the 
clypeus is broad, but shows in the middle a slight descent forward of the dark 
colour: the thoracic and elytral bands are never very broad, but are distinctly 
broader in some individuals than they are in others, the anterior tarsi of the male 
attain fully 12 m.m. in the transverse direction ; the pubescence on the basal joint 
of the intermediate tarsi is intermediate in shape between a narrow triangle and 
an oval form, and that on the second joint forms a patch which has a much less 
width than the termination of the patch on the basal joint: the females have no 
sexual sculpture. 
A female from Formosa agrees with the Japanese individuals ; while another 
from Mantchuria differs only by having a fine but distinct sexual sculpture extend- 
ing along the middle of the wing-case, from near the base to about one-third of the 
distance towards the apex. 
Numerous specimens from China agree with the Japanese form, but some of the. 
females have a well marked sexual sculpture, while others have no trace of it; the 
largest individual is a female with well marked sexual sculpture, and agreeing 
nearly in size with the largest'Japanese female, being fully 28 m.m. long, 15 m.m. 
broad, 9 m.m. high. Ina large male the front tarsi attain quite 13 m.m. in the 
transverse direction. 
Specimens from the Malay peninsula show no further variation than those men- 
tioned above ; the females have no sexual sculpture ; one male is of very diminutive 
size, 22 m.m. long, 117 m.m. broad, 7 m.m. high. 
rom the Philippine islands numerous specimens, (some of which are labelled 
‘Manilla ”) show no differences from the forms already alluded to: and the females 
have also variable sexual sculpture, which is sometimes completely absent. Three 
individuals from these islands differ, however, by their large size and by their form 
which is more dilated behind; the male has the patches of pubescence on the middle 
tarsi much broader, and the females a sexual sculpture on the elytra, consisting of 
