394 PROCEEDINGS OF THE NATIONAL ilWEUM. vol. xxxm. 



with Dana's hrevicaudis, concinnus, and satyrus, and Milne Edwards's 

 dentatus, pallidus, and vulgaris. 



The other subdivision which was to constitute a new genus, differ- 

 ing from Pandarus as Eclithrogaleus differs from Dinematura, was to 

 have Pandarus hicolor for its type, and to differ from the true Pan- 

 darus, first, in the fact that the two anterior thorax segments are so 

 far fused as to have a common four-parted dorsal plate ; secondly, in 

 the somewhat different, more elongated form of the thorax segments, 

 and, lastly, in the fact that the anal laminae are not spine-like, but 

 laminate. 



Under any conditions the authors would have to change their 

 recommendation and leave P. hicolor the type of the true genus, 

 because this is the species upon which Leach originally founded the 

 genus Pandarus. But differences of the sort they mention would 

 have to be far more pronounced than we actually find them in order 

 to become of generic value, and also more constant. 



Different specimens of hicolor show very different degrees of fusion 

 in the first two thoracic plates, and different degrees of elongation in 

 the thoracic segments; and in every species so far as known the 

 anal laminae are flattened and plate-like in the young, and tend to 

 become spine-like on further development. 



It is much preferable, therefore, with our present knowledge of the 

 species, to keep them all in one genus. 



KEY TO THE SPECIES. 



a. Females, free thorax and genital segments covered by paired dorsal plates; 

 sixth segment as a rudimentary plate attached to the posterior sinus of genital 

 segment; abdomen wide and very short, one-jointed; anal laminae modified 



into dentate appendages on the sides of the abdomen near the base b. 



a. Males, carapace with accessory lobes on the posterior margin inside the poste- 

 rior lobes; no dorsal plates; genital segment with two pairs of rudimentary 



legs; abdomen elongate, two-jointed, joints about the same length h. 



b. Lateral plates of second segment more or less fused with median ones of 



third segment, which lie between them and reach beyond their tips c. 



b. Lateral plates of second segment reaching far behind the tips of the median 

 plates of third segment, which lie between them, but are entirely dis- 

 tinct c. 



b. Plates of second segment fused across the mid-line in front of those on third 



segment ; the latter fused inter se, but distinct from the former 



brevicaudis Dana, 1852, p. 397. 

 c. Fused plates of second and third segments about the same size as those on the 



fourth and genital segments; sixth segment plate circular in outline d. 



c. Fused plates of second and third segments much shorter than those on the 

 fourth and genital segments; the latter apparently fused; sixth segment 



plate elliptical in outline and nearly as large as the genital segment 



affinis Beneden, 1892, p. 431. 



c. Fused plates of second and third segments the same size as those on the fourth 



segment, but much smaller, than those on the genital segment; sixth segment 



plate wide, but nearly concealed spinacii-achantias Hesse, 1883, p. 458. 



