10 CHILOPODA. 
9. Lithobius aztecus. (‘Tab. I. figg. 11, 11 a-c.) 
Lithobius aztecus, Humb. & Sauss. Rev. et Mag. Zool. (2) xxi. p. 156 (1869)°; Miss. Sci. Mex., 
Myriop. pp. 116, 117, t. 5. fig. 4°. 
Colour: upper surface uniformly castaneous, or more commonly ochraceo-castaneous, and darker anteriorly and 
posteriorly ; lower surface ochraceous with olivaceous tint; apex of legs and of antenne paler. 
Body moderately robust, attenuated posteriorly, shining. 
Head a little wider than long, finely punctured, the frontal longitudinal groove absent. 
Eyes composed of about 30, mostly rounded ocelli, arranged in about five rews; the posterior ocellus the 
largest. 
Antenne short, not half the length of the body, hairy, sparsely so at the base, composed of about 30 short 
subcylindrical segments ; the apical segment elongate, longer than the penultimate. 
Coxal plate of mawillipedes finely punctured, longitudinally sulcate in the middle, its anterior border 
moderately produced, nearly straight, bearing 7+7 or 6+6 small subequal teeth, of which the internal 
are close set and the external more separated. 
Tergites lightly wrinkled and sparsely hairy; from the first to the sixth with straight posterior border and 
rounded angles; the seventh with its angles slightly produced; the eighth, tenth, twelfth, and fourteenth 
with squared angles, and posterior borders straight, or only very lightly emarginate; the ninth, eleventh, 
and thirteenth with angles produced and sharp. 
Sternites smooth, mesially impressed in the posterior half, and with fainter lateral impressions, the posterior 
sternites and coxe pubescent. — 
Legs: the first pair armed: below, 0, 0, 2, 2,1; anal legs long, longer than the fourteenth pair, which extend 
only as far as the middle of their proximal tarsal segment, armed below, 0, 1, 3, 3, 2; claw double ; coxe 
of thirteenth, fourteenth, and fifteenth armed with one superior and one lateral spine, coxe of eleventh and 
twelfth armed with a superior spine; coxal pores in a single series, elongate, 6, 7, 7, 5 to 4, 6, 6, 4. 
dé. Anal leg with femur marked beneath with a single longitudinal groove; patella much widened, deeply and 
widely excavated above, with two longitudinal grooves beneath; tibia and tarsal segments of normal form. 
2. Femur and patella of anal leg with a single inferior groove, all the segments of normal size and shape , 
generative forceps with two subequal, subparallel, basal spurs on each side, and a stout trifid claw. 
Length up to 24 millim ; average length of adult about 19 millim. . 
Hab. Mexico, Omilteme 7000 to 9000 feet, and Sierra de las Aguas Escondidas 
9500 feet, both in Guerrero (H. H. Smith), Hastern Cordillera!; Guatemaa, Antigua 
and Tecpam (StoJ2). 
The original description of this species is somewhat meagre, but it applies sufficiently 
well to these examples from Omilteme as to leave very little doubt in my mind that 
they are rightly to be named L. aztecus. The species may be at once recognized by its 
short antenne and large number of ocelli. Mr. Smith’s specimens were found under 
decaying logs, in damp thick forest, and also in the clearings. 
The following Central-American species are unknown to me:— 
Lithobius mystecus. 
Lithobius mystecus, Humb. & Sauss. Rev. et Mag. Zool. (2) xxi. p. 156 (1869); Miss. Sci. Mex., 
Myriop. p. 117 [excl. t. 5. fig. 5] (1872); Stuxberg, Ofv. Vet.-Akad. Fork. xxxii. 3, p. 32 
(1875). 
