NOTONECTA.—ANISOPS. 371 
NV. undulata in having the eyes more widely separated behind, and flatter, the anterior 
lobe of the pronotum smoother. With such a limited amount of material, no opinion 
can be expressed as to its validity as a species. The distribution quoted 2, like that of 
N. variabilis, is far too disconnected to be real. 
ANISOPS. 
Anisops, Spinola, Essai sur les Hémipt. Hétéropt. p. 58 (1837); Amyot et Serville, Hist. Nat. 
Ins. Hémipt. p. 453; Fieber, Rhynch. p. 57 (1851); Gen. Hydroc. p. 25, t. 3p; Herrich- 
Schaffer, Wanz. Ins. ix. p. 40, t. 294. figg. B-D. 
This genus seems to be quite as well represented as Notonecta within our limits, 
five species being here enumerated. These are very nearly allied, and they can, 
indeed, be separated only by the pronotal structure of the males, this sex being always 
distinguishable by the angularly dilated lower edge of the basal portion of the anterior 
tibia. The antenne are 3-jointed (Fieber describes them as 4-jointed, counting the 
minute basal portion of the third as a true joint), the genus thus differing from 
Notonecta, in which they are 4-jointed; the posterior tarsi are without claws, as in 
Notonecta (Fieber states that there are two claws to all the tarsi). ‘The intermediate 
femora are received into long deep grooves in the mesosternum, while in Notonecta 
they are free. The ventral carina in the females is not depressed towards the apex, 
but continued as a prominent ridge to a little beyond the tip of the abdomen, where it 
terminates in a projecting point: in the males it is depressed and interrupted towards 
the apex and there becomes much less prominent. All the Central-American forms 
have the anterior tarsi 2-jointed in both sexes, the vertex not produced in the male, 
the pronotum and elytra quite smooth and subhyaline, the coloration of the dorsal 
surface of the body showing through. As in Notonecta, little or no value can be 
attached to the coloration of the upper surface for specific separation. 
Of the American species described by Fieber, I have been able to identify only one, 
and the others are here treated as new. ‘The insects known to North-American 
entomologists as A. platycnemis appear to have been wrongly identified. 
a. Pronotum in the ¢ with four depressions, appearing tricarinate in this sex. 
a’, Head (with the large eyes) nearly as wide as the pronotum in the ¢, a 
little narrower in the ?. 
a’, Body robust; legs stout; interocular space not very narrow behind: . 
length 73-9 mm... . Ce ee ee ee ee ee ee Cartinatus, D. 8p. 
6”. Body moderately robust ; legs comparatively slender; interocular 
space very narrow behind: length 43-6 mm... . pallipes, F. 
b!. Head (with the moderately large, somewhat flattened eyes) distinctly 
narrower than the pronotum in both sexes; legs rather slender, and, like 
the greater part of the body, pale in colour: length63; mm. . . . . albidus, n. sp. 
47* 
