SPIROBOLUS. 81 
Number of segments 44-47. Length of described Q 94 millim.; width 10, width of first tergal plate 8:7, of 
anal segment 6; height of latter 6:3. 
Hab. Mexico, Cordova. 
The above-given diagnosis of the female is taken from an example in the British 
Museum which appears to be identical specifically with the specimens originally 
described by Saussure from the same locality. The information regarding the 
anterior coxe of the male is derived from the Monograph published by Saussure and 
Humbert in 1872. From this it appears that the coxal dilatations are lamelliform, but 
differ from those of all the other Central-American species in being apically bifid. 
9. Spirobolus mystecus. 
Julus mystecus, Sauss. Mém. Soc. Phys. Genéve, xv. p. 569, t. 5. fig. 36 (1860). 
Spirobolus mystecus, Sauss. & Humb. Miss. Sci. Mex., Myr. p. 177 (1872). 
Colour olivaceo-ochraceous, with ferruginous borders to the segments ; legs pale. 
Head as in 8. tepanecus. First dorsal plate with its anterior border strongly emarginate, and not almost 
straight as in S. tepanecus; the anterior angle of the second segment considerably less strongly produced. 
The rest of the segments sculptured almost exactly as in that species. The anal tergal plate obtusely 
rounded, less acute than in S. tepanecus, and not covering the summit of the valves. 
In the male the coxe of the legs from the fourth to the seventh pairs prolonged in the form of a long styliform 
appendix, which is almost or quite as long as the sum of the two succeeding segments of these legs. 
Number of segments 47 (9), 45 (¢). Length of above-described 2 92 millim.; width almost 10, of 
first tergal plate 8, of anal segment 6-2 ; height of latter 6°5. 
Hab. Mexico, Oaxaca [type], San Andres Tuxtla (Jlus. Brit.). 
The above-given description of the female is taken from a specimen from San Andres 
Tuxtla in the British Museum, which in most characters appears to agree with Saus- 
sure’s cotypical examples, but is perhaps rather smoother. 
Comparing the females of S. tepanecus and S. mystecus, Saussure says that the latter 
is very nearly allied to the former, but differs from it in having the lateral sulci on the 
segments extending higher, the second segment obliquely truncate and a little rounded 
at the apex, with the angles less produced, and the anal sternal plate transverse, 
truncate, and in the middle subemarginate. The subsequent discovery of the male of 
S. tepanecus showed that the two species might be readily distinguished by the form 
of the coxal processes of the anterior legs, those of 8. tepanecus being lamelliform and 
bifid and those of & mystecus elongate, styliform, and with simple undivided apices. 
The following species are known to me only from descriptions and figures :— 
10. Spirobolus mexicanus. 
Julus mexicanus, Sauss. Linn. Ent. xiii. p. 332 (1859) ; id. Mém. Soc. Phys. Genéve, xv. p. 566, 
t. 5. fig. 34 (1860). 
Spirobolus mexicanus, Sauss. et Humb. Miss. Sci. Mex., Myr. p. 177 (1872). 
BIOL. CENTR.-AMER., Diplop., September 1908. M 
