28 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
portion of the abdominal cavity, are seated in the central and posterior 
part. The intestinal tube runs through it in nearly a straight direction 
from the base to the apex, and the sacs and tubes which elaborate the 
material for forming the webs are placed in the lower, lateral, and anterior 
parts. In the male, the organs for the secretion of seminal fluid consist 
of two long, narrow, convoluted tubes, occupying the same relative posi- 
tion as the ovaries in the female. They also open outwardly into the 
minute orifice noted above. 
The manner in which the act of pairing between the sexes occurs is a 
matter of doubt, and probably differs among different species. Mr, Cam- 
bridge! reports a case i a perfect apparent coition was 
effected between sexual a 1e male and female spider, 
the palpi not being usec IT have observed what 
seemed to be a similar act in, the pair exes of Agalena noeyia. 
On the other hand, it is evident that the spermatic fluid is conveyed to 
the female parts of gener- 
ation by the male palpi. 
I haye seen and recorded 
this action in the case of 
Linyphia marginata. Menge 
and Ausserer have observed 
that the male spider before 
the act of union emits from 
the sexual aperture a drop 
of sperma on a web made 
for the purpose, which drop 
he then takes up in the 
genital bulb of the palpi and then communicates it to the female. 
With regard to the function exercised by the remarkable organs con- 
nected with the digital joint of the palpi of male spiders, there exists some 
difference of opinion. Taking anatomy as his guide, ‘Treviranus 
Digital arrived at the conclusion that the parts in question are used for 
8 the purpose of excitation merely, preparatory to the actual union 
of the sexes by means of appropriate organs situated near the 
anterior part of the inferior regions of the abdomen, This view of the 
subject, which is very generally adopted, is opposed to that derived from 
physiological facts by Dr. Lister and the earlier systematic writers on 
arachnology, who regarded the palpal organs as strictly sexual; and_ re- 
cent researches, conducted with the utmost caution, have clearly established 
the accuracy of the opinion advanced by that distinguished Englishman.? 
Male 
Organs. 
Fic. 17. Collecting a spider in a box. 
1 For valuable anatomical notes see his “Arachnida,” Eneyclopedia Britannica. 
2 Blackwall: “Reports 14th Meeting British Association Ady. of Sci,” pages 67-69. Also 
“Spiders of Great Brit. and Ireland,” Introduction, page 5. 
