1963] 
Abalos and Baez — Spermatic Transmission 
201 
where the embolus will separate (fig. 2) ; this is particularly con- 
spicuous in Latrodectus geometricus as shown in figures 3 and 22. 
It should be emphasized that the phenomenon described is not the 
accidental breaking-off of the embolus at some place as mentioned by 
Dahl in 1902 ( fide Levi, 1959), Smithers (1944), Levi (1959), 
and lately De Biasi (1962). We have frequently found such differ- 
ent sized parts of the embolus in the female ducts : however we stress 
that what we describe in the present paper is a well differentiated 
sclerite normally retained in the seminal receptacle of the female 
after the male withdraws its palpus. Recently Bhatnagar and Rempel 
(1962) have also observed in a species of Latrodectus a backward 
directed tooth which gets caught in the female genital organs, making 
the apical element break off. 
The apical element of the embolus of the male of a Metepeira sp. 
is stouter and more conspicuous; than that of Latrodectus ; it is 
strongly sclerotized and its calyx-like shape (figs. 4, 23, 24) calls 
to mind a Morning Glory flower. Its size is 80 microns, and it has 
delicate transverse striae. The extreme apex is fish-hook shaped, this 
hook attaching it to the seminal receptacle ; the entrance of the latter 
is situated directly on the epigynum and a connecting canal is lacking, 
matching the short male embolus. In some, two apical male elements 
have been found side by side (fig. 5). Unfertilized adult females 
have rarely been encountered ; in them the potential resting place of 
the male element can be seen to have a cavity opening agreeing in 
form and dimensions with those of the apical element, including the 
place where the hook is to be inserted (fig. 4). 
Fertilized females were always found to contain these male ele- 
ments. The extreme apex of the embolus of unmated males consists 
of the well-differentiated organ described above, with its ejaculatory 
duct opening laterally at its distal end. (figs. 6, 7, 24, 25). 
In Argiope argentata (Fabr.) the apical element is large and 
sclerotized, attaining a maximum length of 1 mm. Its shape is that 
of a curved arrow (fig. 26). The female connecting canal is short, 
sclerotized, funnel-shaped, with a double curve. Fitting into it, the 
apical element of the male adapts itself to the curvature of the duct. 
The male element found in the fertilized female shows an irregular 
zone of rupture from which the ejaculatory duct is separated, dis- 
tinctly visible. 
The ejaculatory duct opens apically. Slide mounts of the epigyna 
of fertilized females showed in some cases that in addition to correctly 
placed male elements, another pair was located in the atrium, indi- 
cating that copulation has been attempted or accomplished more than 
