260 ENTOMOLOGICAL SOCIETY 



posed, provided with two rows of large spines; third appendages with 

 distal joints broken up into very numerous minute articulations: Order 

 Amblypyga. 



In canvassing the question of the recognition of these groups 

 as orders, it has been found that the points of agreement between 

 any two or three of them have usually been common also to other 

 Arachnida outside the Pedipalpi here recognized as a subclass. 

 Notwithstanding the valuable suggestions of Pocock,* it does not 

 appear that the isolation of the various arachnid major groups has 

 even yet been appreciated. With some naturalists the fact that a 

 group is small or monotypic is a reason for refusing to recognize 

 it as of high rank systematically. Although Mr. Pocock is sel 

 dom open to criticism from this standpoint, it does not appear 

 that the second subclass into which he would divide the Arachnida 

 is a natural group, nor is he able to give it more than a negative 

 characterization. It will be difficult to arrange the numerous 

 groups into any such number of major subdivisions or subclasses, 

 as most writers are now willing to admit. Morphological and 

 embryological investigations will furnish light as to the affinities 

 of the various types, but cannot be expected to dispose of the 

 evident differences, or supply connecting links which nature has 

 refused to preserve. The discovery of Hubbardia is, indeed, a 

 reminder that all the returns are^not yet on file, but it is never 

 theless improbable that many important types remain uncol- 

 lected. 



Omitting the mites, the affinities and autonomy of which re 

 main altogether uncertain, it does not appear that the Arachnida 

 can be logically accommodated under less than six primary sub 

 divisions. From their most striking peculiarities these may be 

 briefly characterized as follows : 



Abdomen provided with pectines and ending in a sting, which includes 

 a pair of poison-glands : Subclass Toxicura,t order Scorpiones 



Abdomen without pectines, sting, or poison-glands 



Thoracic stigmata present; posterior legs with a row of large, obliquely 

 "|~-shaped tactile organs; claws pedicellate: Subclass Mycetophora, order 

 Solifuga. 



Thoracic stigmata wanting; posterior legs without such tactile organs; 

 claws sessile 



With jointed, paired, abdominal spinning-organs ; palpi of males modi 

 fied to assist in copulation: Subclass Maripalpi, orders Araneina, Meso- 

 thela. 



Without paired abdominal appendages ; palpi of males not utilized as 

 copulatory organs 



* Ann. and Mag. Nat. Hist., 1893, Ser. 6, vol. xi, p. n. 

 t A new name to replace Ctenophora Pocock, already in use for a major 

 group in Zoology. 



