292 
Psyche 
[Vol. 91 
the distal antennal segment actually touching the syconium. The 
wasp walks over the surface of the syconium in this manner, and 
does not seem to follow any discernable pattern of movement (such 
as spending more time near the ostiole). The assessment period lasts 
from a few seconds to more than five minutes. After assessment the 
wasp may walk off the syconium and search for other syconia on the 
same branch, fly away, or begin the next phase of entry. 
If the wasp attempts entry, she lowers her antennae, and the distal 
five or six antennal segments are pressed flat against the syconium 
surface. The wasp is searching for the ostiole, which she recognizes 
as a lip on the smooth syconium surface. When she finds the ostiole 
she loosens the topmost scale with one of the sharp, sclerotized 
horns on the third antennal segment (Fig. 1). If the upper scale is 
stuck to the tissue layer below, as is often the case on syconia that 
have not yet been entered, she approaches at an angle, hooks one 
horn under the scale, and works the scale free by pushing up with 
her forelegs and head. When the scale is loosened, she is ready to 
begin entry. The legs are spread laterally from the body, and the 
ventral surface of the entire body is flattened against the syconium 
surface. The antennae are forward and also pressed against the 
syconium; the wings are raised perpendicularly to the thorax and 
pressed together; and the abdomen, which has a flexible pleural 
region and mobile tergites and sternites, is compressed dorso- 
ventrally. The wasp now pushes her antennae and head under the 
topmost scale of the ostiole. As the wasp pushes her way forward 
she arcs her body at approximately a 120° angle. She slowly disap- 
pears, and as her thorax passes through the topmost scale her up- 
raised wings detach. When several wasps enter a single syconium, a 
tuft of wings can be seen at the entrance to the ostiole. As the female 
passes under the top scale, she contacts and pushes her head under 
the lip of the second scale, and continues walking the helical ostiole. 
The antennae distal to the fourth or fifth segment detach during 
entry. Also, it has been reported that the unusual mandibles (Fig. 1) 
are used to aid in entry (Ramirez 1970b). Wasps are not always 
successful at passing through the ostiole, and are sometimes found 
dead within the scales of the ostiole, frozen in the remarkably flat- 
tened attitude taken during entry. 
Female Phase of Syconium; Ovipostion and Pollination by Wasps 
After wasps arrive in the central cavity of the syconium they 
oviposit and pollinate during the day or two before they die. At this 
