88 THE CANADIAN ENTOMOLOGIST. 



A CLASSIFICATION OF THE NORTH AMERICAN SPIDERS. 



BY NATHAN BANKS, WASHINGTON, D. C. 



The author has frequently been asked why he did not make a key for 

 the families of spiders. He has answered that a correct key was 

 impossible. But as such questions are getting more numerous, and 

 connected with a desire to know something about spiders, the author has 

 decided to put together what he could as a contribution to the classification 

 of our spiders, principally for the use of those who are unable to obtain 

 the costly works necessary for study. 



I shall consider the family the highest group separated by definite 

 characters ; not but what certain families possess transition forms, but 

 that the groups higher than the families are not defined by definite 

 characters, but by tendencies. Two groups above the families I shall 

 recognize, the higher the division, the lower the section ; the section 

 embracing certain families, the division one or more sections. To these 

 I shall not attempt to make a key, but. only designate their general 

 characters and the families which they embrace. In the key for the 

 families I shall be arbitrary ; but in the system which follows I shall try 

 to indicate the natural affinities. 



The classification of spiders is difficult because of the few characters 

 that can be used. This is not often understood by those who study 

 nsects. Let the entomologist cut off from his insect the wings, the 

 antennae, one pair of palpi, unite the abdominal segments, obliterate all 

 sutures, and how many characters will he have left ! Yet even then he 

 will have far more than the student of spiders can find in his subject. 



A few words in explanation of the characters used in the key. The 

 body of a spider is very definitely divided into two parts — the anterior. 

 the cephalothorax ; the posterior, the abdomen. Upon the anterior part 

 of the cephalothorax are the eyes ; the region they occupy is called the 

 eye region. The eyes are arranged in transverse rows ; abbreviations 

 referring to them are frequently used, as S. E. side eyes ; A. E. anterior 

 eyes ; P. E. posterior eyes ; M. E. middle eyes ; from these are made 

 compounds, A. S. E. anterior side eyes, etc. Dark coloured eyes are 

 diurnal, light coloured eyes are nocturnal. The region between the 

 anterior row of eyes and the anterior or clypeal margin of the cephalothorax 

 is called the clypeus or fillet. A groove on the meson toward the 

 posterior part of the cephalothorax is called the median groove. There 

 are more or less distinct furrows extending from the groove to the sides, 



