334 
Psyche 
[December 
and 5 had 0 there. This filling effect may be due to intersexual 
competition, in which more females pile up at the preferred location 
before overcoming the effect of the male present. 
Not enough data were available to test the effect on position of 
increasing number of males or when two or more males were present 
in a host in this category, but generally the females preferred segment 
5 and the males segment 3 as before. When all the data for females in 
this category were lumped into three subcategories in which either 1, 
2, or 3 males were present with the females, there was no significant 
change in the positions of females as number of males increased 
(p>0.05). In other words, the data analyzed this way indicated either 
no intersexual competition, or that the intersexual competitive effect 
of 1 male was as strong as the effect of 3 males. 
Position of Xenos pallidus in the host when the number of females 
was less than the number of males: 
With one female present in a host, increasing number of males 
from 2 to 8 had no significant effect on position of the males (p>0.05). 
This result is different from that of the preceding section where we 
saw more intrasexual competition between females in hosts with one 
male. In addition, with 2 females in a host with 3 to 8 males, no 
significant position changes in the males were observed (p>0.05). 
These data seem to mean that the intersexual competitive effect on 
position is stronger than the intrasexual effect and the intersexual 
and intrasexual competitive effect of females is stronger than that of 
males. 
There were not enough data to test female position in this category, 
but where one female was present with 2 to 8 males, 17 of 23 females 
were under the fifth tergite. Where two females were present with 3 to 
8 males, 25 of 33 females were under the fifth tergite. In this category, 
males were rather scattered among segments 2-4. In summary, no 
intrasexual competition is seen in this category, but females seem to 
take their preferred position and suppress position changes of the 
males. 
Discussion 
Notes on small collections of pallidus have been given by several 
investigators. Hubbard (1892) confined and studied a nest of Florida 
P. annularis for three weeks. He noted that parasitized hosts rarely 
left the nest, and states that the parasites extrude from the abdomen 
