ON THE CHILOPODA OF NORTH AMERICA. 



13 



genus Lithobius; but Mr. Newport says, that in all his specimens of the family the 

 larger depressed surface is a deep elongate oval, whilst the smaller excavations are 

 transverse, oval and furrow-like. We find, among the American species of the Litho- 

 biidse, a group in which the larger surface is scarcely depressed, with the smaller 

 excavations round and almost punctiform. This we have indicated as a distinct 

 genus, with the name of Bothropolys. 



The specific characters of the Lithobiidse are derived from the number of ocelli, the 

 shape of the dental lamina with the number of teeth, the shape, color and structure 

 of the scuta, &c. The number of the eyes in the adult is fixed within narrow limits 

 for each species. But when the young Lithobiid emerges from the Fig. 5. 



egg, it possesses but a single pair of eyes, besides wanting some 

 of its segments. In the genus Henicops, (not yet discovered in 

 this country,) the single pair of ocelli remain as a permanent cha- 

 racter; but in the other genera the number of eyes are gradually 

 increased until adult life. Mr. Newport seems to think the number of labial teeth a 

 good specific character, but we have found it to vary considerably. 



Gen. 1. LITHOBIUS, Lmch* 



Antennte multiarticulatee. Caput latum, complanatum. Labium antice denticulatum, medium sulcatum, 



emarginatum. Cox* excavationibus rnagnis, ovatis, serie unico in facie depressa dispositis. (Fig. 5.) 

 L. multidentatus, Newp. — L. brunneus, segmento cephalico margine postico elevato ; antennis elongalis, 

 sparse pilosis, subsegruento impuactato ; laminis dentalibus distinctis, margine antieo fere recto, angulis 

 externis anticis vix subproductis, denticulis 12 — 19 aroiatis; ocellis utrinque 32 — 37; scutorum anti- 

 corum marginibus et postieis et lateralibus sed scutorum posticorum lateralibus solum elevatis. 

 L. multidentatus, Newp., Linn. Trans, xix. p. 365; Catal. Brit. Mus. Myriapoda, p. 17. 

 L. multidentatus, P. Gervais, Apteres, iv. p. 236; et Tabl. des Myriap. (Exp. dans L'Amerique du Sud 

 part, sept.) p. 29. 



This species is very similar to Bothropolys nobilis. Indeed the only specific differences 

 noticeable are that this species attains a rather larger size, and has the anterior margin 

 of the dental lamina straighter, with the anterior external angle scarcely subproduced. 

 The geographical distribution appears to be identical. Our Arkansas specimen differs 

 slightly from the others, having the external anterior angle of the dental lamina 

 slightly subproduced. The Texan individual has but twenty-six pairs of eyes, but is 

 probably the young of the species. 



Specimens belonging to the Smithsonian Institution. 



345 



10 



271 



3 



282 



2 



277 



i 



275 



l 



i 



South Illinois. 



St. Louis, [Missouri. 



Cook Co., Illinois. 



R. Kennicott. 



D. Geo. Engelmann. 



It. Kennicott. 



Ft. Towson, Red River, Ark. Dr. L. A. Edwards, U. S. A 

 En route from N. Orleans to , B. Andrews. 

 Galveston. 



*Linn. Trans, xi. p. 3S1. 

 4 



Lin. 10— 16 

 " 10—12 

 " 11—13 

 " 12 

 " 9 



