STRONGYLODESMUS. 173 
anal segment triangularly conical and truncate; sternal plate triangular. Zegs long and slender. 
Sterna wider than long. Phallopods with basal segment (coxa) without calcar; distal segment stout, 
subcylindrical, furnished apically with a slender hooked process (the seminal stile). 
Type, S. cyaneus, Sauss. 
Distribution. Mexico. 
This well-marked genus differs from all others known from Central America in 
having pores upon the 8th, 11th, and 14th segments, as well as upon the 5th, 7th, 9th, 
10th, 12th, 13th, 15th to 19th segments as in Polydesmoidea with normal pore- 
formula. In other respects Strongylodesmus most resembles Rhachodesmus. 
1. Strongylodesmus geddesi, sp.n. (Tab. XIII. figg. 5-5.) 
Colour (in alcohol) pale olive-green, with the keels tinted with yellow; antenne green like the head and 
dorsal surface; legs markedly yellower than the body. Head rugulose, with frontal sulcus. Antenne 
long, segments 2 to 6 subequal in length, distance between antennz less than length of their second 
segment. Upper surface of the metazonites uniformly and closely covered with granules, with exception 
of the extreme edges and the lateral thickening of the keels. Back nearly flat, with high horizontal keels ; 
an indistinct transverse row of small tubercles along the posterior border of the median area of the 
tergal plates. The jirst tergal plate wide with the keels well developed, the anterior angle rounded, 
postcrior angle sharp and rectangular, anterior border of the plate straight from side to side, posterior 
border mesially lightly emarginate and elevated, posterior border of keels oblique and straight. On the 
keels from the 2nd to about the 16th the anterior and posterior borders are more or less convex, 
on the 2nd and 38rd the anterior border is strongly convex and the posterior border nearly straight ; 
but upon the segments of the mid-region the posterior border is more convex than the anterior; the 
anterior angle of the keel is rounded, with a distinct but small antero-lateral tooth ; the posterior angle 
is nearly square, but from about the 7th backwards its angle bears a small backwardly directed 
tooth; there is also an angulation of the lateral border just beneath the pores; posterior border of 
16th to 19th directed more and more backwards, the 18th and 19th being triangularly spiniform and 
posteriorly uplifted. Caudal process of anal tergal plate curved, triangular, truncate; sternal plate wide, 
triangular, with setiferous tubercies far apart and some distance behind the extremity. Sternal areas 
wide, transversely oblong, hairy. Lateral area of metazonites granular, of prozonites smooth. Legs long ; 
third segment a little longer than the first, both longer than fourth + fifth segments. Phallopods 
short and thick; thickly hairy externally and in the hollow internally ; ending distally on the inner 
aspect in a somewhat bowl-shaped hollow, the proximal border of which is armed with two short 
spiniform teeth, the distal border being angled above and passing below into a large, wide, semicircularly 
curved inwardly directed, sickle-shaped ramus, the seminal stile, which lies in a horizontal plane when 
the phallopod projects forwards, the apices of the two normally crossing each other; behind the superior 
angle of the hollow there is a forwardly directed tuft of bristles, and between the two teeth of its 
posterior or proximal edge there is a backwardly directed triangular gutter running back towards the 
excavation of the femoral portion. Seminal processes long and slender. Legs of first pair short, but 
otherwise unmodified, 
Length of ¢ 41 millim., width 5. 
Hab. Mexico (Patrick Geddes, in Mus. Brit.). 
2. Strongylodesmus cyaneus. 
Strongylodesmus cyaneus, Sauss. Linn, Ent. xiii. p. 827 (1859) *; Mém. Soc. Phys. Genéve, xv. 
p. 587, t. 3. fig. 20 (1860) *; Sauss. & Humb. Miss. Sci. Mex., Myr. p. 55 (1872)*; Attems, 
Denk. Akad. Wien, Ixviii. p. 418 (1899) *; Carl, Rev. Suisse Zool. xi. p. 555 (1908) ’. 
Strongylodesmus viridis, Peters, Mon. Ak. Wiss. Berlin, 1864, p. 547 (sec. Saussure & Humbert) °, 
