HANSEN AND SORENSEN, THE TARTARIDES. 33 



V. Genera and Species of Tartarides^ 



The Genera. — As already mentioned, four genera have 

 been established, viz. Schizoynus Cook (Nyctalops Cambr., 

 Schizonotus Thor.), Trithyreus Kraep. (Tripeltis Thor., Triplo- 

 7nus Cook), Artacarus Cook and Huhhardia Cook. On p. 4 it 

 is stated that Huhhardia Cook is identical with Triplomus 

 Cook; in the opinion of Cook the only difference between 

 them is that Huhhardia has »a pair of narrowly triangulär 

 chitinous plates» on the dorsal surface of cephalothorax. but 

 these plates which constitute the tergite of the first thoracic 

 segment, exist not only in the two species on which Thorell 

 founded his genus Tripeltis, but in every species of the group. 

 — In the analytical key to the genera Cook writes : »Posterior 

 part of cephalothorax entire ; trochanter and patella of maxillse 

 with a large spine-like process in males: Genus Schizomus», 

 in contradistinction to »Posterior part of ceplialothorax with 

 a median suture; trochanter and patella without such pro- 

 cesses in either sex» in Artacarus, Triploynus and Huhhardia; 

 furthermore he writes: >>Suture of posterior part of cephalo- 

 thorax chitinized ; flagellum of first pair of legs with the third 

 joint distinctly broader tlian long, the four following about 

 as broad as long: Genus Artacarus.» Above it is shown that 

 it is impossible to comprehend the real meaning of this »chi- 

 tinized suture» in Artacarus, as Kraepelin could not separate 

 the species in question from the female Schizomus crassicau- 

 datus Cambr. ; I am inclined to suppose that Artacarus is only 

 a Schizomus with a whitish stripe under the middle of the 

 second thoracic tergite, but the question can of course not 

 be settled. A glance on the plates will show that not the 

 sHghtest generic value can be ascribed to the character drawn 

 from the dimensions of the third joint in the »flagellum of 

 first pair of legs». If the armature of the palps in the male 

 Schizomus crassicaudatus Cambr. should be considered a generic 

 character, the genus Schizomus can only comprise that species. 

 and the tribe must be divided into a considerable number of 

 genera in order to establish equivalence between the genera 

 themselves, but a perusal of the following descriptions of the 

 forms will show that the species of this group are so closely 



^ This chapter has been worked out by H. J. Hansen alone. 

 Arkiv för ZooJvgi. Bd 2. N:o S. 3 



