1977] 
Jackson — Dictyna and Mallos 
277 
spiders tend to transport prey to the hub of the web before feeding 
(Robinson and Olazarri, 1971). Although data were not collected, 
it was noticed that arthropod carcasses tended to be concentrated 
near the nests of the solitary and the communal, territorial species; 
and many of the feeding dictynids were near their nests at the time. 
These observations suggest that dictynids transport prey to their 
nests, although actual transport has not been seen. Billaudelle 
(1957) noted that D. civica carries prey from the periphery to 
the center of the web. 
Most dictynid webs tend to be 2-dimensional; i.e., most of the 
silk of the web is in a single plane. In contrast, the communal 
webs of M. gregalis tend to be 3-dimensional; and the nests are in 
the interior of the webs, beneath the surface sheet on which flies 
are captured. Although flies were occasionally pulled into the in- 
terior of webs by spiders, in the vast majority of cases the prey was 
fed upon at the capture site in communal webs in the laboratory. 
Returning to the hypothesis proposed at the beginning of this 
paper, is the prey of M. gregalis relatively large and dangerous 
compared to that of other dictynids? Diptera are apparently the 
primary prey of most species. Since Diptera such as muscids, culi- 
cidids, etc. would not seem especially dangerous for dictynids, dif- 
ferences in the danger associated with different prey would not 
seem important. Adult females of M. gregalis , the largest sex/ age 
class, tend to weigh 4 to 21 mg, adult Musca domestica tend to 
weigh 10 to 20 mg (Witt, et al., 1978). If prey of M. gregalis is in 
this weight range, then prey tends to range from approximately 
equal in size to individual spiders to a few times larger. In the 
solitary and in the communal, territorial species, prey were often 
smaller than the spiders. However, the difference in relative prey 
size among species is not absolute. Many prey of solitary and 
communal, territorial species were equal to or larger in size than 
the spiders (see also Bristowe, 1958; Wiehle, 1953). 
Since prey sizes overlap for different dictynids, we need quanti- 
tative data from which variances can be calculated for relative prey 
size. Data from the natural habitats of M. gregalis in Mexico are 
especially needed. It will be tentatively concluded that M. gregalis 
preys primarily on relatively large prey. However, the differences 
in relative prey size do not seem dramatic. In a sense, the social 
organization of M. gregalis seems very different from that of the 
other dictynids, with great numbers of spiders living and feeding 
