RHYSODESMUS. 193 
longer than the palmar aspect of the segment; auxiliary 
branch about half its length and rising obliquely upwards, 
then forwards . 2. 1. 1. 1 ew ee ew eee  montezume. 
2. Keels with the posterior border lightly convex and the posterior 
angle squared or even a little produced, the angles rarely 
rounded and blunt (smithi, 9), and then the posterior border 
is nearly straight with very shallow basal notch. 
k, Principal branch of phallopod viewed from the side showing 
scarcely any upward curvature, when viewed from below the 
smooth portion is seen to bend somewhat abruptly inwards 
and then forwards; principal branch about as long as the 
palmar portion ; auxiliary branch about half as long as the 
palmar portion, directed slightly upwards, then curved down- 
wards and forwards, inter-ramal space semioval; generally 
conspicuously banded yellow and brown, posterior half of 
metazonite yellow: female robust; male moderately slender; 
posterior border of keels slightly convex, posterior angle 
squared or a little produced on median segments . . . . inustus. 
k’, Principal branch of phallopod when viewed from the side 
showing apical upward curvature, when viewed from below 
the inward bend not abrupt or subgeniculate, but evenly 
convex or obtusely angular. 
/. When viewed from within the palmar portion of the distal 
segment of the phallopod is seen to be much longer than 
the auxiliary branch and only a little, if at all, shorter 
than the entire main branch, which is more abruptly 
incurved. 
m. Principal branch strongly arcuate seen from the side; 
auxiliary branch very thin, about one-third the length 
of the palmar portion, which, if anything, exceeds the 
length of the main branch; colour as in R. inustus, but 
form more robust . . . 2... 2 ee we ee) flavocinetus. 
m*‘. Principal branch lightly arcuate when seen from the 
side, and a little longer than the palmar portion ; 
auxiliary branch stouter; proportions as in R. inustus, 
but the yellow on the posterior portion of the meta- 
zonites mostly restricted to a median patch. . . . . notostictus. 
/’, When viewed from within the palmar area of the phallopod 
is seen to be short, much shorter, indeed, than the main 
branch and not much, if at all, longer than the auxiliary 
branch, the principal branch more evenly curved. 
n. Auxiliary branch broad, blade-like, somewhat suddenly 
narrowed at the apex; principal branch long, evenly 
attenuated and curved; size larger, 2 when contracted 
about 40 mm. in length; keels larger, anterior crest 
BIOL. CENTR.-AMER., Diplop., December 1909. 2¢ 
