1968] 
Barth — Behavior of Eurycotis 
279 
turbances are frequent in the mating chambers and usually result 
from females attempting to mount and feed on the male’s abdominal 
surface. In these cases both members of the pair show repeated 
vertical jerks of the abdomen, either alternately or in unison. If this 
does not discourage the courting individual, the pair resorts to 
lateral kicking. On several occasions, a copulating pair was observed 
to turn on their sides as though trying to dump the intruder off. 
This turning appears to be initiated by the female and results from 
the full extension of the legs on the opposite side. However, this 
movement may not necessarily result from the interference of other 
animals, as it has been observed on several occasions in copulating 
pairs which were not being disturbed by any other animal. If the 
pair shows any locomotion during copulation, the female predominates, 
dragging the male along behind in the manner characteristic of cock- 
roaches. 
Homosexual and Pseudofemale Behavior 
Spontaneous male-male courtship sequences appear to be quite rare 
in this species, though they have been observed on two occasions. 
Male-male courtship sequences have also been observed upon ex- 
posure of isolated males to virgin females, though it is not certain 
that the frequency of such sequences is increased appreciably in this 
situation as it is in most cockroach species (Barth 1964; 1968a, 
Roth & Barth 1967). Unlike females, males only mounted males 
which were performing the vibration movement. With this single 
exception, male-male courtship sequences do not appear to differ from 
male-female unsuccessful copulation attempts. 
The Role of Various Releasers in the Courtship Sequence 
A tentative schematic representation of the mating behavior of 
E. floridana indicating the possible releasers of the various stages in 
the sequence is shown in Fig. 1. This diagram presents a relatively 
simple version of the mating behavior of Eurycotis. Some sequences 
do indeed follow this pattern, but departures from it are so frequent 
that one can’t be sure that it represents an accurate picture of this 
species’ mating behavior. The suggested releasers are quite specu- 
lative, though there is some circumstantial evidence for some of them, 
as will be discussed below. 
As we have seen, the female appears to be the usual initiator of 
courtship in this species. The most plausible explanation for the 
release of active courting behavior in females upon their exposure 
to males is that the males are producing a volatile pheromone which 
