92 TH?: CANADIAN ENTOMOLOGIST. 



A SYSTEM OF SPIDERS. 



Division I. — Gnaphosce. 

 This embraces but one section. 



Section I. — This section contains the spiders which have the mandibles 

 moving vertically. With the exception of one doubtful form they have 

 four lung sacs. There is no epigynum in these forms, the male palpal 

 organ is very simple, consisting of a bulb tapering on one side to a tube ; 

 the tarsus of the palpus is not at all modified. They are a tropical group 

 and include the largest and most powerful spiders known. They have 

 developed from primitive spiders like Filistata. 

 Family i, Atypidce. 



This includes but one genus, Atypus, whose members are quite rare. 

 Family 2, Theraphosidce. 



These are the tarantulas. We have two sub-families. 



\ Inner distal angle of maxillae slightly prolonged ; palpi somewhat 



) lateral Eriodontince. 



^ Inner distal angle of maxillae not prolonged ; palpi terminal. 

 [ llieraphosince. 



The Theraphosince may be divided into two tribes. 



^ Three claws to tarsi Trionchi 



\ Two claws to tarsi Dionchi 



The Dionchi have one genus Eurypelma ; the true tarantulas. The 

 Trionchi may be separated into two groups. 



[Median groove longitudinal Mecicobothri 



\ Median groove transverse ^picephali 



Family 3, Hypochilidce. 



This is represented by one peculiar genus Hypochihis. In the shape 

 of the body and the length of the legs it has great resemblance to a 

 Pholciis. It has a calamistrum and cribellum. The only species in the 

 U. S. spins a web similar to some Therididce. 



Family 4, Catadysidce. 



Represented by one genus Catadysas, which has not been seen since 

 described by Hentz. It stands on the dividing line between the typical 

 members of this division and the more typical spiders, in having but two 

 lung-sacs. 



