NO. 1154. AMERICAN MEKOCHETA— COOK. 465 



tinctly truncate latenul; in .'ill cases there is a distinct raised margin, 

 which is slightly broader hiterad; the anterior margin is straight, 

 while the i)Osterior is concave toward the end and convex near the base, 

 there being a very slight notch or emarginatiou where the carina joins 

 the segment. 



Rei)ngnatorial pores not evident, unless located in the very large and 

 deep cavities found close to the anterior base of the carina?. These cavi- 

 ties are distinct on all segments from the third to the penultimate, those 

 of the third segment being smaller than the others. 



Supplementary margin very short, entire; the' segments are very 

 slightly constricted at the transverse suture, and the anterior subseg- 

 meiit is very short and not sculptured. 



Last segment nearly as high as broad, with traces of rounded promi- 

 nences, the surface otherwise smooth; margin thin, even, slightly pro- 

 duced mesad; on the under surface, slightly removed from the margin, 

 are two pairs of fine seta* equally distant from each other. 



Anal valves flat, smooth, not margined, much exceeded by the edge 

 of the last segment; preaual scale rounded, triangular, the setse rising 

 from punctations not located on tubercles, 



Copulatory legs consisting of two unequal branches, a slender spine- 

 like structure, simple and gradually narrowed to a sharp ])oint, and a 

 subclavate, much larger, distally bifid arm, which is hirsute on its lateral 

 surface for about three quarters of its length; on its inner surface it 

 has a large longitudinal groQve, into which the slender arm may be laid. 



This species is named for my friend Prof. F. S. Earle, who kindly 

 assisted me in collecting a suite of specimens near Auburn, Alabama, 

 in July, 1890. The most favored localities seemed to be woods con- 

 sisting of deciduous trees with a mixture of pine, the same situations 

 affected by the curious glomeroid form previously described as Onome- 

 ris undericoodii. On account of the roughened dorsum and adherent 

 particles of dirt, Desmomis is even more inconspicuous than the smooth 

 and polished Onomerin. Occurring witli these were occasional speci- 

 mens of the terrestrial isopod crustacean Armadillidium, and these 

 three independent approximations to.the same form, habits, and place 

 in the economy of nature was very striking, and furnished instructive 

 evidence on the possibilities of parallel development. The case is also 

 worthy of note as furnishing an instance of close approximation in 

 form, coloration, and habits, without evident reason for supposing that 

 any implication of mimicry is involved. 



DESMONUS PUDICUS (Bollman). 



(Plate XXXII, lige. 2a, 2b.) 



Sphwriodesmus pudicua Boll.max, EntomoloKica Americana, 1888, IV, p. 3; Hull. 

 IT. 8. Nat. Mus., 1893, No. 46, p. 7."). 



Type.— 1^0.173, U.S.N. M. 

 Locality. — Arkansas. 



Proc. N. M. vol. xxi 30 



