402 Mr. G. W. Kirkaldy on the 
Varieties. 
The hemielytra are usually rich scarlet, with black 
membrane, but the latter hue often extends beyond the 
apical margins of the clavus and corium ; the scarlet also 
varies much in shade, graduating in one direction to pale 
greenish-white through pale yellow, pale olive-green, 
deep yellow, orange and pinkish, and in the other 
through crimson and violet-red to deep violet-black, 
though, in the last, the sutures of the hemielytral divi- 
sions are usually narrowly violet-red; in some specimens 
the apex of the corium is black, from the base of the 
membrane to the margins of the hemielytra in a straight 
line, and the rest of the hemielytra are rich crimson. 
The hemielytra are rarely maculate, occasionally the 
centre of the clavocorial suture has a more or less pro- 
nounced black smudge about the centre. It may be 
convenient to propose the varietal names ceres for the 
pale coloured forms and hades tor the southern violet- 
black race. Herrich-Schiffer (J. c., p. 43) notes a variety 
with a large ochreous central stripe on the scutellum, 
while Fieber (/. c., p. 475) describes among the varieties 
with red hemielytra: (1) “Schild schmutzig-gelb mit 
braunem Grund,” and (2) “Schild braun, mit gelblichem 
Rand ”—these three varieties I have not seen. 
The crimson forms are well distributed over the 
Western United States, Mexico, and Colombia; the 
pale: forms I have seen from Lower California, Mexico, 
Costa Rica, and Colombia; the melanochroic forms are 
much rarer and more local, though occurring in the same 
localities as the pale forms. 
This is the most aberrant species of Notonecta, differing 
from all the others in the proportions of the pronotum 
and scutellum; it is wider in proportion to its length, 
and the humeral angles are more accentuated. It shows 
affinities in several details to Hnithares, and is perhaps 
nearer in structure to the primitive Notonectid than any 
other existing species of its genus. 
2. Notonecta montezuma, sp. n. 
HTead narrow at base, similar to that of N. mexicana, noto- 
cephalic lateral margins fairly straight, diverging from the base, 
vertex two and a-half to three times as wide as synthlipsis. 
