452 INVERTEBRATE MORPHOLOGT. 



the two sliort oviducts unite to form a vagina with which 

 may be associated receptacula semiuis {rs), though more usu- 

 ally these structures open independently in front of the 

 genital orifice and may be single, or paired, or in some cases 

 even three in number. The testes are cy- 

 lindrical structures whose long, slender, and 

 frequently-contorted vasa deferentia unite 

 just before opening to the exterior. A 

 remarkable copulatory organ is formed by 

 the terminal joint of the pedipalp of the 

 male (Fig. 207), which bears upon its inner 

 surface a process containing a spirally- 

 coiled tube. This tube opens at the ex- 



^ „„„ „ tremity of the process, and is filled by the 



Fig. 207.— Pbdipalp ■ t ■.^ , n •, • 



OP Male Spider spider with spermatozoa, and during copu- 



(af ter bertkau). lation is inserted into the receptacula semi- 



nis of the female. 



The males are usually smaller than the females, and their 

 approaches are frequently resisted by the latter, who en- 

 deavor to capture and destroy the persistent swains. In the 

 Attidse a process of courtship has been observed to occur, the 

 male posturing before the female and displaying to their best 

 advantage the highly-colored hairs with which the body is 

 covered. The ova are in many forms {Lycosa) attached to 

 the under surface of the abdomen, while in others they are 

 enclosed in a silken cocoon which may either be carried 

 about by the female or suspended in the webs or deposited in 

 protected situations. 



Two suborders are recognized, according as there are two 

 pairs of lung-books or only one. The Tetrapneumones in- 

 clude the forms with two pairs of lung-books, among which 

 are the Trap-door Spiders, Cteniza, already mentioned, and the 

 Tarantula, Mygale, the largest of all the spiders and reputed 

 to attack even small birds. The Dipneumones have but a 

 single pair of lung-books, the majority of living spiders be- 

 longing to the suborder. Some, such as Epeira, Agelena, Tege- 

 naria, Theridium, and Segestria, spin webs, while others catch 

 their prey by their rapid movements (Lycosa) or by suddenlv 

 springing upon it (Attus). 



