CARBONIFEROUS ARTHROPOD FA UNA I 79 



that of Brongniart which was based upon the quite different 

 European insect fauna of Carboniferous times. Most of the new 

 species here recognized are assignable to genera already known 

 — 'an interesting fact which would indicate that at the early- 

 period when these insects lived there were but comparatively 

 few types, and that the number of genera, even in restricted 

 groups, had not reached the specialization of today. 



In the preparation of this paper, acknowledgment is due to 

 the cheerful aid of Professor Stuart Weller, of the University of 

 Chicago, and to the generosity of Curator F, C. Baker, of the 

 Chicago Academy of Sciences, for the loan of specimens 

 belonging to that institution. 



CLASS ARACHNOIDEA. 



Order ANTHRACOMARTI. 



Family Architarboidae Karsch. 



The genera of this family may be separated in the following 

 manner: 



Legs unusually long and slender: basal abdominal segments large: spin- 



neretts present ------- Kustarachne 



Legs thickened; basal ventral segments of the abdomen usually shortened; 



no spinning organs ........ ^ 



2. Coxae radiating from a triangular sternum - - Anthracomartus 

 Coxae radiating from a median pit or ridge - - - - - 3 



3. Basal segments of abdomen strongly angulated; cephalothorax promi- 



nent, not markedly constricted from the abdomen - Geraphrynus 

 Basal segments nearly transverse, though often crowded - - 4 



4. Cephalothorax narrower than the abdomen, or markedly constricted 



from it, suborbicular, the front more or less broadly angulate 5 



Cephalothorax shorter than the abdomen, but not constricted from 

 it, transversely orbicular, the front rounded - - Architarbus 



5. Cephalothorax less than one-half as broad as the abdomen; legs short; 



large species ------ Hadrachne gen. nov. 



Cephalothorax and abdomen of nearly equal breadth; legs compara- 

 tively long though stout; species less than one-half the size of the 

 former Geratarbus 



Hadrachne gen. nov.' 



Stout-bodied; cephalothorax small, angulate anteriorly and 

 transverse posteriorly, its sides nearly straight and more or less 

 continuing the outline of the abdomen without a lateral con- 



' d5p6s, " stout ; " dpdxvVi " spider." 



