502 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



7. Araclinida. 



Pairing of Tegenaria guyonii— Organs in the Male Abdominal 

 Sexual Region.* — Mr. F. M. Campbell describes some observations 

 which he made on the deposition of semen by T. guyonii. He also 

 gives an account, which may be taken as typical of the species, of 

 the pairing of thii'teen couples in confinement. Two cases are de- 

 scribed in which during confinement the males killed the females after 

 union, and an instance is also given of an attempt to impregnate an 

 immature female, which was also destroyed by the male. In these 

 cases hunger could not have been the cause of the attack. The author 

 explains these occiu-rences, and also the accounts of females destroying 

 males after union, by the suggestion that those instincts w^hich are 

 habitually practised throughout the far greater portion of the life of 

 the species, and on which it is dependent, would scarcely be suspended 

 for a longer period than is necessary for sexual union. Spiders fre- 

 quently eat one another, and such an occurrence after pairing is only 

 curious if considered apart from their habits. "When the sexual 

 desire is satiated their actions would be again directed by the 

 dominant instinct of destruction which would be stronger if a general 

 excitement be supposed to follow the union. 



The external abdominal sexual region is marked by a slight con- 

 vexity, in front of which is placed transversely a row of transparent 

 spines. Two j^apilla-like processes are situated just above the opening 

 of the genital sinus. Neither of these organs have hitherto been 

 noticed. 



The spines are tubular, point backwards, and project just beyond 

 the convexity. They are generally twenty-four in number, and are 

 placed singly or in groups of two, three, or four. A tube runs from 

 each spine, and, after making many and sudden convolutions, ends in 

 a gland of a pear-shaped form. The contents of the glands have a 

 high refractive power. 



The papillae, are erectile, and consist of pointed scales surrounding 

 a fascicule of fibres which internally diverge, and are lost in the 

 connective tissue lining the inferior side of the genital sinus. The 

 points of the scales rest on one another, thus giving to the processes 

 a conical form. 



The question arises as to the function of these glands and papillae. 

 They are not found in the females, nor has the author yet met with 

 them in immature males, while their position denotes some share in 

 the primary sexual process. As to the papillae, he would suggest that 

 their fibres when protruded are used for arranging or supjiorting the 

 triangular sheet, or for assisting the collection of semen by the palpi. 

 It is more easy to limit the conjectui'es as to the purpose of the glands 

 to two alternatives: — (1) To pour their secretion on the semen when 

 deposited ; or (2) to spin threads which would guide the semen to the 

 silken sheet of which they might form a part. 



* Jouru. Liun. Soc. Loud. (Zool.) xvii. (1883) pp. 162-74 (2 pla.). 



