8 
Psyche 
[Vol. 87 
inseminated, may be fertile as is shown by the presence of corpora 
lutea in their ovarioles. 
4) Sexual Behavior of Leptothorax provancheri 
The sexual behavior of L. provancheri is, as far as observed, 
identical with that of Formicoxenus nitidulus (Buschinger 1976), 
Harpagoxenus sublaevis (Buschinger 1972) and other species of the 
Mychothorax group and their social parasites. This means that 
sexually active females emerge from the nests, climb atop of the nest 
chamber or any other object in the formicary, raise the gaster and 
present, with the stinger extruded, a sexual pheromone. With L. 
provancheri we observed, in the morning between about 9 and 11 
a.m., several intermorphs and ergatomorphs exhibiting this “Lock- 
sterzel” behavior (Fig. 1). After all males had died by 15 September in 
colonies no. 3 and 10, the females remained active until 29 September 
when the colonies were put into hibernation temperatures. The males 
are attracted by poison gland secretion of the females, as in the other 
species cited above. They mount the females (Fig. 2), and the 
copulation differs by no means from what was observed in Formi¬ 
coxenus. The behavior of alate females could not be studied. 
Fig. 2: L. provancheri male mounting a calling intermorph. 
