24 
Psyche 
[March-June 
In the rearing boxes as well as in the glass tubes they were pro- 
vided water and gnats ad libitum. In the frames the spiderlings were 
fed with de-winged houseflies. A weighed fly was given one time 
every three days only when a web had been built, thus rewarding the 
spiders for high frequency of building. 
The individual weights of the spiders (accuracy o.i mg) were 
recorded every week and web-building was recorded every day. Each 
web was photographed then collapsed by the experimenter, and ana- 
lyzed for size, shape, fine structure and regularity (Reed et al., 
1965). The dates of the molts of each spiderling were recorded and 
the length of the first leg was measured on the molted limb (ac- 
curacy in mm.). 
In the following pages the initials FG and SG are used in place 
of fast growing males and slow growing males. Statistical com- 
parison between the two groups (SG & FG) where not specifically 
mentioned was made with the Wilcoxon test, adapted by White for 
unpaired measurements (White, 1952). 
RESULTS 
Of 31 spiderlings that reached maturity in set I, twelve were 
identified as males. There were 14 males out of a total of 29 animals 
in set II. The number of males in each set is significantly repre- 
sentative of the expected 50% probability of males in a population 
(Binomial test, p = 0.01 in each case). 
Some characteristics of the male 
The adult males of Araneus diadematus have enlarged black palps, 
relatively narrow elongated abdomens, and weigh about a fifth of the 
adult females. Adult females are characterized by long yellow palps 
and a globulous abdomen (Figure 1). Other characteristics of the 
males include banding of the legs that is generally darker, a lack of 
humps on the abdomen, and a modified second tibia that is stronger 
than in females and has short spines (Levi, 1971). 
The enlarged palps appear at the end of the next-to-the-last molt, 
whitish instead of black, and blacken between the two last molts. 
One animal exhibited enlarged palps prematurely two molts before 
the last one and four other animals after the last molt, but these 
were exceptions. 
After the last molt, when they reached sexual maturity and maxi- 
mum weight, the males stopped building webs. Sekiguchi (i955) 
reported that a male of Araneus ventricosus, in the laboratory, did 
