MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 59 



facets, aud not depressed. Antennas ra,ther long, the joints subclavate, joint 6 not much longer than 4 ; joints 3 and 

 5 of the same length ; joiut 6 rather thick at the end; joint 7 short, thick, and conical, much more so than usual. 



Body segmeuts swollen aud full, becoming suddenly depressed on the front edge; the swollen portion with 

 numerous raised hues or ridges, with deep concave valleys between; the ridges projecting behind in an acute point. 

 The segment nest to the head rather narrower than the head, "with the posterior two-thirds ridged; the sides of the 

 segments are somewhat swollen high up ou the sides, but not so conspicuously as in Pseudotremia. Legs rather 

 stout and larger than iu Pseudotremia; the first pair rather short and broad, with a regular comb of stiff setas on 

 the inner edge of the termiual joint. The seventh and ninth pairs of legs, i. e., the pair immediately preceding and 

 following the geuital armor, are like the others, not being in any way modified, as in Pseudotremia, etc. The 

 genital armature is large and better developed than in any other genus of the family ; the outer lamina large, 

 stout, spatulate-mucronate at the tip ; inner lamina much shorter than the outer, and with two long acute forks ; 

 repugnatorial pores difficult to find. 



The genus may be recognized by the long, slender body, tapering to a point, and by the very short conical sev- 

 enth antennal joint; by the ribbed, swollen segmeuts, which are very numerous ; by the seventh and ninth pairs of 

 legs being normal, like the others; and by the short, broad first pair, with the regular comb of setae on the terminal 

 joint. 



The genus as here defined will apply to the two southern European species Lysiopetalum carinatum Brandt and 

 L. ilhjricum Latzel, except th it they are setose, while our species is not. I am indebted to Dr. Latzel for specimens 

 for comparison. 



In proposing the genus Spirostrephon, Brandt (Bull. Sci. Acad., St. Petersb., 1840) regarded Say's Julus lactarius 

 as the type species, and adding that the eyes are in a triangular area, he indicates its generic difference from Cambala 

 annu/atus, with which it has been so often confounded. 



Although I had originally retained Brandt's name Spirostrephon for our species, yet upon receiving from Dr. 

 Latzel authentic types of European Lysiopetalum, it is plain that our S. lactarius is congeneric with them. The 

 name Spirostrephon should, theu, be considered as a synonym of Lysiopetalum. It is difficult to see why Brandt 

 should have separated lactarius from his L. carinatum. 



In his Eecueil, page 42, Brandt thus characterizes his genus Lysiopetalum: "Laminae pediferae omnes liberae, 

 mobiles, cutis ope cum parte abdominali corporis cingulorum coujunctae. Frons ante antennas dilatata et deplanata 

 in maribus in simul depressa." The two species mentioned under the generic diagnosis are Lysiopetalum faitidissimum 

 (Savi) and L. carinatum Brandt. 



Again, on page 90: " Subgenus seu genus II, Spirostrephon Nob." is thus characterized, and he apparently regards 

 it as a subgenus of Julus: "Gnathochilarii pars media fossa baud instructa, sede jus loco aream tetragonam planam, 

 plica seu linea derata duplici, superiore breviore et inferiore longiore, supra et infra terminatam, sed sutnra longi- 



tudinali hand divisam offerens. Spec. 27. Julus (Spirostrephon) lactarius Nob Ditfert habitu a Julis genuinis 



et Julo (Lysiopetalo) fcetidissimo et plicato affinis apparet. Annuli corporis, quorum posteriores brevissimi, incluso 

 anali 53. Pedum paria 95. Longitudo 10 to ll m ; latitudo summa f IH . Oculi triangulares — Julum laclarium protypo 

 generis Cambala Grayi habuissem, quum figura ab hocce zoologo sub nomine Cambala lactarii data" (Griffith Anim. 

 Kingd. Insect., PI. 135, fig. 2). The generic characters are not very applicable in distinguishing the genus, the men- 

 tion of the type alone rendering it possible to understand what the genus is. 



The synonym will be further discussed under Cambala. In 1844 Newport, having been misled by the specimen 

 of Cambala annulata alleged to have been sent by Say as the type of his Jul its lactarius, places the latter in his genus 

 Platops, which he proposes, with a doubt, thus: "Genus Platops? mini." The generic characters apply well to the 

 present species, S. lactarius. 



Dr. Wood, in his Myriopoda of North America, does not attempt, for want of material, to define the genus. 

 Professor Cope characterizes this and the next genus thus : 



Annuli without pores Spirostrephon. 



Annuli with two pores on each side the median line Pseudotremia. 



As we have seen, there are pores in Lysiopetalum, while the " two pores" of Pseudotremia are two of the three 

 setiferous tubercles on the side of each segment. 



The genus appears thus far to be represented in North America by but a single species, which ranges from Mas- 

 sachusetts west to Iowa and south to Florida and Louisiana, while in southeastern Europe Lysiopetalum is rich in 

 species. 



Lysiopetalum lactarium Say. Plate IX, figs. 3, 3a-3h. 



Julus lactarius Say, Journ. Acad. Nat. Sci., Phil., ii, pt. i, 104, 1821. 



Spirostrephon lactarius Brandt, Bull. Sci. St. Petersb., 1840. Recueil, 90, 1840. 



Platops lineata Newport, Ann. Mag. Nat. Hist., xiii, 267, April, 1844. 



Lysiopetalum lineatum Gervais, Apteres, iv, 133, 1847. 



Cambala lactarius Gervais (iu part), Apteres, iv, 134, 1847. 



Bcasia spinosa Sager, Proc. Acad. Nat. Sci. Phil., 109, 1856. 



Cambala lactaria Gervais, Exped. l'Amer. du Sud (Castelneau), Myriop., 17. 



"Reana chinosa Saeger," Gervais, Exped. l'Amer. du Sud (Castelneau), Myriop., 14. 



Spirostrephon lactarius Wood, Myriop. N. Amer., Trans. Amer. Phil. Soc, Phil., PI. ii, figs. 11, 11a, 192, 1865. 



