3 6 
Psyche 
[March-June 
his own set. Only the FG females of the set I accepted the males, 
while both FG and SG females of set II accepted the males. How- 
ever, the small number of males limited the number of trials and 
did not permit us to know statistically which of the females (FG 
or SG) were the most successful in mating. 
The FG males cannot mate with females of their own set, but we 
may assume that they can find females of other sets in a natural 
habitat which are mature at the same time. The SG males can 
mate with the FG females of their own set, permitting limited in- 
breeding. This is merely a possibility since different sets in nature 
may have mature females at the same time. 
Comparison of the webs of SG and FG spiders 
FFeb changes during development : 
Webs for the FG and SG males were compared on the basis of 
the spiral area, mesh size and thread length. 
The spiral area of all webs built by males in both groups and both 
sets showed a general increase until reaching a maximum area during 
the period between the last two molts. The spiral area decreased in 
size thereafter. Four males mentioned earlier, who did not follow 
the general web-building pattern (they built webs until they died), 
showed no decrease in spiral area in their final webs. This further 
supports speculation that they died before achieving full development 
through a complete series of molts. In contrast, the spiral area of 
the females of Araneus diadematus and Neoscona vertebrata in- 
creased until the last three months, after which time the catching 
area does not change significantly (Witt & Baum, i960). The 
catching area of the females of the golden garden spider, Argiope 
aurantia , showed a growth and decline, the peak size coinciding 
roughly to the time of last molt and sexual maturation (Reed, Witt 
& Scarboro, 1969). 
An essentially upward linear growth in mesh size throughout the 
lifetime occurred for 11 of the males studied. For the 12 other 
males the mesh size increased until reaching a plateau during the 
last intermolt. Witt, Rawlings and Reed (1962) have pointed out 
that the mesh size of the female webs of Araneus diade?natus show 
also an increase until the last molt, and then reach a plateau. But 
Argiope aurantia shows a linear growth in mesh size throughout the 
lifetime (Reed, Witt & Scarboro, 1969). 
The thread length fol’ows the same pattern as the two other pa- 
rameters with a peak during the last intermolt and then a decrease. 
Argiope aurantia and Araneus diadematus females have been shown 
