1971] 
Jackson — Web of Araneus 
13 
zontal web of Cyrtophora citricola in Kullmann’s (1957) study of 
this peculiar spider. However, we have been able to find no detailed 
descriptions of thread connection fine structure. 
In the study reported in this paper, we investigated the fine 
structure of most of the types of thread connections which are found 
in the web of Aranens diadematus Clerck. Within the web there 
may be between 1000 and 1500 locations at which one thread is 
fastened to another thread (Fig. 1). Mooring threads fasten the 
web to some non-thread structure and may be continuous with 
some of the frame threads (Witt, et al. , 1968). There are frame 
thread to frame thread connections, forming Y’s with the stem of 
each Y being a mooring thread. Each radial thread is fastened to 
a frame thread. Occasionally, a radius will be in the form of a 
Y-structure at its peripheral end; the stem of the Y connects with 
the hub; and each arm, or secondary frame thread (Peters, 1939), 
fastens to either a frame thread or a radial thread. However, the 
majority of the connections within the web are the viscid or sticky 
spiral to radius connections in the trapping zone. Most of these 
are at points at which the sticky spiral thread extends from both 
sides of the radius. Occasionally, especially in the lower portion 
of the web, the sticky spiral thread meets the radius but does not 
continue on the other side. In the strengthening zone (Savory, 1952) 
or notched zone (McCook, 1889), non-sticky spiral threads are 
fastened to radial threads. The strengthening zone surrounds the 
apparently disorderly network of threads in the hub (McCook, 
1889). Non-sticky spiral thread to radial thread connections are also 
present in the provisional spiral, a structure which is removed as 
the sticky spiral is added. Each of these types of connections will be 
described except for those at which a sticky spiral meets the radius 
but does not continue on the other side. 
METHODS 
All thread connections surveyed in this study came from webs of 
laboratory reared adult female cross spiders ( Araneus diadematus 
Clerck). Each spider was kept in a 51 x 51 X 9 cm aluminum 
frame with removable glass doors and was provided with one house 
fly twice per week, water daily, and controlled conditions of light 
and temperature (Witt, et al ., 1968). The age (3 to 4 months 
since emergence from the egg cocoon), weight (88 mg to 134 mg), 
and time between food consumption and web construction ( 1 to 8 
days, with the majority at 1 day) were relatively constant for spiders 
used in this study; and within these ranges for these factors, no cor- 
