166 
Psyche 
[Vol. 87 
D Both Celaenia (Forster and Forster 1973) and Taczanowskia 
(Eberhard in press) adopt the same daytime resting posture as 
that of Mastophora. 
In sum, the data suggest that the traditional groups of Cyrtarach- 
neae (including Cyrtarachne, Pasilobus, Poecilopachys, and four 
other genera), Mastophoreae (including Mastophora, Dichrostichus, 
Cladomelea, and three other genera), and Celaenieae (including 
Celaenia and Taczanowskia ) (Roewer 1942) should be placed 
together in the same section of the subfamily Araneinae. 
It is reasonable to ask why natural selection would favor such 
radical reduction in trapping webs in this group. The use of volatile 
substances mimicking prey pheromones could make large traps 
superfluous, and one can imagine a gradual reduction in webs 
accompanying an increasingly precise mimicry. The development of 
an adhesive capable of restraining moths could also result in selection 
for simplified webs designed to maximize prey interception efficiency 
(Chacon and Eberhard 1980). It is not immediately clear however 
why an effective sticky trap like a bolas should be abandoned 
altogether as in Celaenia, Taczanowskia, and, on occasion, M. 
dizzydeani. It seemed that wind conditions may have influenced the 
type of trap M. dizzydeani used, since the most elaborate web (three 
balls) was made when the air was unusually still, and spiders 
apparently hunted without balls during particularly windy periods. 
Under windless conditions a more elaborate trap might be advan¬ 
tageous since 1) an attractant would diffuse in many directions and 
the direction from which prey might approach would be less certain, 
and 2) the sticky material would be especially effective since it would 
not dry out as quickly. On the other hand, strong wind (or relatively 
dry conditions of any sort, including relatively small body size) would 
make investment in sticky material which evaporated quickly less 
advantageous. As noted above, this line of reasoning could also 
explain the apparently greater frequency of hunting without balls in 
younger M. dizzydeani. 
This consideration may have consequences regarding the as yet 
unestablished trapping method of newly emerged M. dizzydeani. If 
my observations of spiderlings apparently hunting without a bolas 
are typical and correctly interpreted, then they may provide an 
explanation for the rows of bristles on the inner sides of the anterior 
legs of spiderlings (and incidently suggest that mature males, which 
also have these bristles, may feed after they mature; perhaps, as 
