OF WASHINGTON. 255 



Schizonotidse, I left my single, somewhat dilapidated specimen 

 with him. 



In his " Revision of the Uropygi," Professor Kraepelin includes 

 Artacarus under Schizonotus, a disposition to which I am un 

 able to assent. Having since secured additional material, I find 

 that the large spine-like processes of the trochanter, patella, 

 and tarsus of the maxilla of the male of Schizomus, as de 

 scribed and figured by Professor Kraepelin, do not occur in 

 Artacarus. 



The posterior sclerite of the cephalothorax has a median suture 

 indicated by a difference of structure and color in the integ 

 ument, though not membranous as in Triplomus and Hubbardia. 

 Finally, the caudal appendage of the male is diamond-shaped in 

 outline, not abruptly cordate-capitate as in Schizomus. 



The genera of Hubbardiidas are thus four in number ; they 

 may be distinguished as follows : 



Posterior part of cephalothorax entire ; trochanter and patella of maxillae 

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



Posterior part of cephalothorax with a median suture; trochanter and 

 patella without such processes in either sex 



Suture of posterior part of cephalothorax chitinized; flagellum of first 

 pair of legs with the third joint distinctly broader than long, the four fol 

 lowing about as broad as long: Genus Artacarus. 



Suture of posterior part of cephalothorax membranous; third joint of 

 flagellum as broad as long, the others distinctly longer than broad 



Cephalothorax with transverse suture simple : Genus Triplomus. 

 Cephalothorax with a pair of narrowly triangular chitinous plates lying 

 in the transverse suture : Genus Hubbardia. 



THE SYSTEMATIC POSITION OF THE HUBBARDIID^E. 



In Hubbardia the segmentation of the cephalothorax is carried 

 a step farther than in the allied genera in the direction of the 

 condition described by Grassi for his truly remarkable Koenenia 

 mirabilis, so that it becomes somewhat more probable that that 

 aberrant type can be associated with the subclass Pedipalpi, not 

 withstanding the fact that the second pair of appendages, the so- 

 called maxilla3 of Thelyphonus and Tarantula* function in 



* The application of this name has been the subject of much debate, not 

 ably between Professor Kraepelin and Mr. Pocock. Linnaeus, having a 

 specimen, described a species (P/ialajigium rent forme} which he identi 

 fied with a form described and figured in Brown's History of Jamaica. This 

 reference Mr. Pocock proposes to employ as the type of the genus 

 Tarantula described by Fabricius from a specimen supposed to repre 

 sent Phalangium reniforme Linnaeus. Professor Kraepelin properly 



