AGELENA N;VIA WALCKEN.ER 17! 



fertilized one by one and appear in the median genital 

 opening. 



(b) Male. Two testes in the shape of long and thin coiled 

 tubes are situated in the abdomen under the intestine. They 

 continue as vasa deferentia and unite shortly before their joint 

 genital opening. The latter occupies the same position as the 

 corresponding opening of the female in the genital groove. 

 The copulatory apparatus of the male has no connection what- 

 ever with the sexual organs producing the sperm, and is formed 

 by the modified last joint of the pedipalpi, as described above. 

 Thus it happens that Agelena, like all other spiders, has two 

 organs of copulation corresponding to the two openings of the 

 sperm receptacles in the female. When the male becomes ma- 

 ture with the last moult, he weaves a small "sperm" web into 

 which he ejects the sperm through its genital opening and pumps 

 it then into the sperm reservoirs of his palpi. If now the male 

 finds a mature female, he introduces the embolus of one pedipalp 

 into one of the receptacles of the female and fills it with sperm. 

 After a few minutes the other embolus is introduced into the sec- 

 ond receptacle and copulation is finished. 



Development. The fertilized eggs are laid into a specially 

 prepared sheet which, when filled, is formed into a closed cocoon. 

 Development is direct. The spiderlings resemble their parents. 

 Maturity comes only with the last moult, before which the 

 spiders are unable to reproduce. The life cycle occupies an 

 entire year. 



Instructions 



i. Place a mature female in its natural position in a dish 

 with alcohol and examine in reflected light under dissecting 

 microscope. Make a half page drawing of the dorsal surface. 

 Label cephalothorax and abdomen. On the former label cara- 

 pace, cephalic groove, thoracic sulci and eyes. At the end of 

 the abdomen label the upper spinnerets. The heart is visible 



