RHAGOVELIA. 131 
RHAGOVELIA. 
Rhagovelia, Mayr, Verh. zool.-bot. Ges. Wien, xv. p. 445 (1865) ; Reise der Novara, Hemipt. p. 180; — 
Signoret, Bull. Soc. Ent. Fr. 1877, p. liv; Carpenter, Ent. Monthly Mag. xxxiv. p. 109. 
Becula, Stal, Hemipt. Afric. iii. p. 167 (1865). 
Neovelia, Buchanan White, Journ. Linn. Soc., Zool. xiv. p. 487 (1879). 
Of the ten described species of this genus, all but three are American ; eight others 
are now added from within our limits. -~&hagovelia is well characterized by the 
3-jointed tarsi *, and the long, deeply-fissured, terminal joint of the intermediate tarsi. 
In this fissure there is a series of long ciliated hairs, arising from a common stem, 
which are probably extended, fan-like, when the insect moves about on the surface of 
the water; these hairs are sometimes partly extended in dried specimens, but they are 
usually hidden within the fissure. All the true Rhagovelie live upon the surface of 
fresh water, the single described salt-water form, &. plumbea, Ubler (=Trochopus 
marinus, Carp.), from the Antilles and Florida, belonging to Trochopus, to which a 
second species is here added. In the apterous specimens the pronotum is usually 
extended backward so as to cover, and to appear fused with, the mesonotum ; but in 
R. tenuipes (as in the two species of Zrochopus) there is a well-defined suture across the 
pronotum towards the apex, reducing it to a short lobe. In the winged examples the 
backward growth of the pronotum is much more pronounced, the posterior portion 
being often produced into a long spiniform process. In two of the Central-American 
species, as well as in the Antillean f. elegans, Uhler, the posterior tibie are armed 
with a long hook at the apex. 
The American species known to me may be thus differentiated :— 
a. Posterior tibiz with or without a straight spur at the apex. 
a’, Penultimate joint of the intermediate tarsi not or very little longer 
than the apical joint; elytra extending to a little beyond the 
abdomen, with regular longitudinal nervures ; pronotum (in the 
winged forms) acute or produced into a spiniform process behind ; 
abdomen moderately long. 
a', Posterior femora more or less incrassate, at least in the ¢. 
a'", Intermediate femora not constricted at the middle. 
a‘. Posterior femora greatly incrassate and dentate, and the 
posterior tibiz also conspicuously dentate or denticulate, 
in the ¢. 
a’. Posterior legs moderately elongate; the tibiz strongly 
sinuous in the ¢. 
a’, Anterior tibize not dilated in the ¢. : 
a’. Posterior femora enormously incrassate and multi- 
dentate, and the posterior tibie armed with three 
long teeth,inthe d. . . . . . . . « + + = ©Crassipes, N. 8p. 
* Buchanan White states that in Neovelia the tarsi are 2-, 3-, 1-jointed, but this is certainly a mistake. 
* 
17 
