44 
Psyche 
[March-June 
Poetsch has shown (1963), that cocoons of a. single species of 
spider hatch at different times. This presumably provides an ad- 
vantageous distribution of egg-production over a period of time. The 
two cocoons studied hatched at different times, and the males of 
set II, which hatched fifteen days later, grew faster than the males 
of set I (significant only for the SG males). Between the sets the 
rapid growth occurs also at the expense of endurance and maybe 
weight increase. Differential growth occurs between the sets as well 
as within the sets, favoring the distribution of mature animals over 
a period of time. This suggests that during the favorable season 
mature males and females can mate and produce cocoons at various 
times, providing the species with a better chance to survive any 
drastic crisis due to the environment. 
The relative quick maturation of males favors mating between 
animals of different sets and of different behavior instead of inbreed- 
ing. This allows the species to conserve a genetic pool with high 
selective potentialities, Dobshansky, 1951). 
During development the last intermolt was distinct from the other 
stages. During this period the males built more webs, ate more food 
per day, and grew faster than during the other stages. The time 
separating the last two molts was generally longer than the time 
separating any other two successive molts. Sexual differentiation 
also took place during this period, and we may assume gametogenesis 
too. This would explain why the males need more food and a longer 
time to complete the last stage of development. The importance of 
the requirements during this time must make it the most difficult 
for the males. 
Summary 
The offsprings from two cocoons of Araneus diadematus , hatched 
at different times and placed in individual frames, were studied in 
the laboratory during the life-span of the males. During this time, 
the characteristics of the body (weight and size), the frequency and 
the parameters of the webs, the number and date of the molts, and 
the amount of food eaten were recorded for each animal. The 
spiders could choose their feeding schedules through their building 
behavior. 
The males built and increased their weight only until the last 
molt, in contrast to the females which continued both building 
and increasing their weight long after the last molt. During the 
