62 
Psyche 
[June-Sept. 
being due to the pigmentation of the skin of the developing 
embryo. In some species, notably Stilbula cyniformis, there 
is a distinct bluish reflection in the older eggs. The egg 
stalk, of course, retains its original color. 
The very incomplete information on the habits of the 
planidia during their free-living period indicates that they 
attach themselves to worker ants and are thus carried into 
the nest, where they transfer to the larvae. Those of Stilbula 
tenuicornis were found upon the twigs and foliage of aphid- 
infested plants frequented by worker ants in their search 
for honeydew. In the alert position they stand erect upon 
the caudal sucker and the body is braced by the long spines 
of the posterior abdominal segment and by the spinelike 
projections of the pleural plates. They quickly attach them- 
selves to any moving object that comes within reach. 
In the study of Kampala terminalis and Kapala sp. in Cuba 
it was found that the planidia have a highly developed 
capacity for jumping. They stand erect upon the caudal 
sucker and, without any distinguishable preliminary move- 
ments, hurl themselves into space. The horizontal distance 
covered is about 10 millimeters, which is approximately 
one hundred times their own body length. This habit, if 
general in the family, would explain how Parapsilog aster 
Iseviceps Gahan and Kapala terminalis , which oviposit in 
incisions in leaves, reach their hosts. In their foraging the 
Odontomachus workers do not ascend trees and conse- 
quently, if the parasite planidia remained upon the foliage, 
they would have no opportunity to attach themselves to an 
ant carrier and be transported into the nest. By jumping 
they reach the ground, where they may encounter worker 
ants of the host species. 
The intervention of a carrier other than the adult of the 
host species is apparently obligatory in Psilogaster anten- 
natus Gahan. The eggs of the parasite are deposited on the 
leaf surface only in the immediate vicinity of an egg of 
Selenothrips rubrocinctus (Giard), and the eggs of the two 
species hatch simultaneously. As the thrips larva scrambles 
about among the erect eggs of Psilogaster the planidia of 
the latter attach themselves to it and are carried away. 
They remain attached by their mandibles to the thrips larva, 
