26 CHILOPODA. 
P. denticulatus differs from P. limbatus in being wrinkled and granular above, the 
latter being described as ‘ sublevis.” 
RHYSIDA. 
Rhysida, Wood, Journ. Acad. Phil. v. p. 40 (1863). 
The following synopsis will serve to show the diagnostic characters of the three 
Central-American species referred to Rhysida :— 
a. Femur of the anal leg armed with about 7 strong spines, 3 of which 
are arranged externally in a longitudinal series on its lower surface 
(terga in the posterior half of the body at least with elevated margins). /ongipes, Newp. 
6. Femur of the anal leg without spines. 
a’. Lateral margins of the terga in the posterior half of the body 
elevated (testibus Humbert & Saussure, and Meinert) . . . .  celeris, Humb. & Sauss. 
b'. Lateral margins of all the terga, except the last, simple, aud un- 
raised 2. ee we ee ee ee ee ew ee ee emmarginata, Porat. 
1. Rhysida immarginata. (Tab. III. figg. 1, 1 ac.) 
Branchiostoma immarginatum, Porat, Bih. Sv. Vet.-Ak. Handl. iv. no. 7, p. 24 (1876) °. 
Branchiostoma indicum, Kohlr. Arch. f. Naturg. 1881, 1, p. 67°. . 
Branchiostoma gymnopus, Kohlr. loc. cit. °*. 
Branchiostoma subspinosum, Témosvary, Term. fiizetek, ix. p. 65 (1885) °*. 
Branchiostoma celebense, Haase, Abhandl. Zool. Mus. Dresden, no. 5 (1887), p. 86 (var. of 
immarginatum) °. 
Branchiostoma ceylonicum, Haase, loc. cit. (var. of gymnopus) °. 
Hab. Mexico, Ciudad in Durango (forrer); British Honpuras, Stann Creek, Belize 
(Robertson) ; GUATEMALA, near the city (Stoll); Nicaragua, Greytown (Janson) ; PANAMA, 
Volcan de Chiriqui (Champion).—ORIENTAL REGION. 
This is, I believe, the correct synonymy of the species, to which are ascribed the 
Central-American examples. But seeing that others ‘may possibly hold a different 
view as to the correctness of referring the New World examples to the Old World 
species, the following description of the American examples has been prepared as a 
check upon the determination of them :— | 
Colour olivaceous or ochraceous ; legs pale green or testaceous; shining. 
Head wider than long, somewhat coarsely and sparsely punctured, not sulcate, covered posteriorly by the first 
tergite. 
Antenne moderately long, composed of from 18-21 segments, of which the basal 2 and half the third are 
naked, and the rest pubescent. 
Mawillipedes indistinctly punctured ; prosternal plates not large, wider than long, slightly diverging, with 
convex border bearing four sharp teeth, of which the external is the smallest; femoral tooth large and 
subdentate. 
Tergites smooth or at most lightly wrinkled, from the third or fifth bisulcate; margins simple and unraised. 
Sternites smooth, without impressions and without sulci. 
Anal somite: tergite without median sulcus, not impressed behind; plewre punctured throughout, produced 
into a longer or shorter stout process, which is terminated by two spines, without lateral or superior 
