226 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vol. 50 



dominal segment. There is a distinct carina on the basal article 

 of the uropoda, which is also present in M. flavimarginatus, but the 

 post-lateral lobes of the basal article of the uropoda differ from those 

 of M. flavimarginatus. These characters are not sexual ones, but 

 are constant in both sexes of the two species. 

 The type is in the possession of Dr. O. F. Cook. 



MESARMADILLO HASTATUS, sp. nov. 



Body ovate, extremely convex, contractile into a ball. Surface 

 smooth, punctate. Color, dark brown, with bands of wavy yellow 

 lines on either side of the median longitudinal stripe of brown, 

 and with the margins of all the segments, the uropoda, the coxopo- 

 dites of the first segment, the head, and the antennae all light yellow. 



Head wider than long, 3 mm. : 9 mm., with the frontal margin 

 slightly produced in the middle. Front not margined, but con- 

 tinuous with the epistome, which is convex about the middle. The 

 eyes are small, composite, and situated at the lateral margins. The 

 first pair of antennae are small and inconspicuous. The second pair 

 have the first article short ; the second article is twice as long as the 

 first ; the third is as long as the second ; the fourth is a little longer 

 than the third ; the fifth is a little longer than the fourth. The flagel- 

 lum is composed of three articles, the first one of which is a little 

 shorter than either of the other two, which are subequal in length. 



The first segment of the thorax is nearly twice as long as any 

 of the following segments, which are subequal. The first segment 

 is 7 mm. long; the following six segments are each 4 mm. in length. 

 The coxopodites of the first thoracic segment appear as wide and 

 thickened plates extending along the lateral margin, but not reach- 

 ing by some distance the post-lateral angles. They are separated 

 from the segment 'by a deep, longitudinal groove, and are cleft 

 posteriorly by a very shallow fissure, the inner portion being much 

 smaller than the outer portion. Coxopodites are present on the an- 

 terior portion of the second and third segments on the underside 

 in the form of thickened ridges, with crests sharply carinated. 



The first two segments of the abdomen are covered laterally by 

 the seventh thoracic segment. The lateral parts of the three fol- 

 lowing segments are well developed and are directed backward. The 

 third segment is a little longer than the first, second, and fourth, 

 which are subequal, and the fifth is slightly shorter. The sixth or 

 terminal segment is triangular at the base and has the apex pro- 

 duced in a long triangular process, with sides converging gradually 

 to an acute extremity. The basal article of the uropoda is large, 

 somewhat quadrangular, and occupies all the space between the lateral 



