STEMMIULUS.—POLYDESMOIDEA. 109 
STEMMIULUS. 
Stemmiulus, Gervais, Ann. Soc. Ent. France, (2) ii. p. xxviii (1844); Aun. Sci. Nat. (3) ii. p. 70, 
t. 5. fig. 11 (1844) ; Ins. Apt. iv. p. 200 (1847). 
Stemmatoiulus, Cook, Silvestri. 
1. Stemmiulus bioculatus. 
Julus (Stemmiulus) bioculatus, Gerv. Ann. Soc. Ent. France, (2) ii. p. xxviii’. 
Stemmiulus bioculatus, Gerv. Ins. Apt. iv. p. 200, t. 84. fig. 7”. 
Stemmatoiulus bioculatus, Silvestri, Boll. Mus. Torino, xi. no. 254, p. 2 (1896) °; op. cit. xii. no. 305, 
p- 2 (1897) *. 
Colour ashy-black. 
Head with a vertical sulcus on the summit; antenne long, the second segment the longest. First tergal plate 
with its sides angled and acute. Last tergal plate posteriorly angled, not surpassing the valves. Legs 
of first and second pairs with five segments, those of the second pair smaller than the first. In the male 
the legs of the first pair bear a spine on the lower side of the third and fourth segments ; those of the second 
pair are short and three-jointed, the proximal segment being thick and the distal strongly attenuated and 
hairy at the base beneath. Legs of the third pair thicker than the others, with the claw wide. Anterior 
pair of appendages of the copulatory apparatus bicolumnar, the external column larger and hairy at the 
apex, with long flagellum rising from its base posteriorly ; posterior pair of appendages very small. 
Number of segments 42. 
Length 26 millim.; width 1:8. 
flab. Panama, Darien, Punta Sabana (Festa 3 +).—Co.omata ! 2, 
Group VII. POLYDESMOIDEA. 
Body consisting of 19 or 20 segments in the adult (20 in all the known Central-Amerivan genera); each 
segment consisting of a compact ring, the sternal and pleural elements firmly united to the terga; the 
terga usually furnished with lateral outgrowths, laminate or tubercular, which carry the pores when 
present. Pores very variable, sometimes absent, but typically found upon the 5th, 7th, 9th, 10th, 12th, 
13th, 15th to 19th segments. 20th segment with a caudal process varying in shape from square to 
cylindrical. 19th segment without legs; segments from the 5th to the 18th with two pairs of six-jointed 
legs ; the 4th segment with a single pair of legs, and only two pairs of legs representing the 3rd, 2nd, and 1st 
segments. Antenne consisting of only 7 distinct segments. Hyes absent. Mouth-parts well developed ; 
mandibles bisegmented. Gnathochilarium with stipites widely separated by a triangular pronotum and 
two elongate lingual lobes. Generative orifices of the female lying behind the legs of the second pair. 
Generative ducts of the male perforating the coxee or basal segments of the legs of the second pair, without 
any definite penis. Copulatory organs of the male composed of a pair of phallopods which are the modified 
anterior legs of the seventh segment; these emerge from a usually oval fossa and are generally exposed, 
rarely retractile ; each consists of a basal segment or coxa, which is commonly provided with a slender 
curved process, the calcar, and of a distal segment carrying the seminal duct; these segments may be 
simple or highly complicated, sometimes showing division into three elements, the femoral, tibial, and tarsal, 
and sometimes quite undivided; the seminal style is long or short and is usually guarded by one or 
more processes or lamine. Coleopods absent; the posterior legs of the seventh segment being normal. 
Distribution. Cosmopolitan outside the Arctic and Antarctic Zones. 
The question of the classification of the Polydesmoidea, principally with regard to 
