158 
Psyche 
[Vol. 89 
they have the same complex mixture of cuticular hydrocarbons as 
their host termite. In addition, we report that at least one of these 
beetles (X. hexagonalis ) biosynthesizes its hydrocarbons. 
Methods and Materials 
Portions of several colonies of R. virginicus were collected in 1979 
from pine logs in Harrison, Jackson, and Stone Counties, Missis^ 
sippi. The beetles were separated from the termites, counted by 
species, and stored at — 20° C until used. A total of 230 beetles was 
collected: 10 P. howardi, 140 T. depressus, and 80 X. hexagonalis. 
Cuticular hydrocarbons from pooled samples (by species) were iso- 
lated and separated as previously described (Howard et al., 1978). 
Hydrocarbons were characterized by gas-liquid chromatography 
(GC) retention times and by electron impact (El) and chemical ioni- 
zation (Cl) mass spectrometry (Howard et al., 1980b; Jackson and 
Blomquist, 1976). Double bond stereochemistries were determined 
by comparison with standards using argentation thin-layer chroma- 
tography (AgNCE-TLC) (Kates, 1972). 
In vitro biosynthesis experiments were conducted as previously 
described {Howard et al., 1980a) using 60 X. hexagonalis collected 
from a single colony of R. virginicus in September 1979. 
Radioactivity was assayed by liquid scintillation counting for 10 
minutes at about 85 percent counting efficiency. All counting was 
done with a standard deviation of less than 5 percent. A portion of 
the isolated hydrocarbons was assayed for total radioactivity. The 
remainder of the material was separated by AgN0 3 -TLC into satu- 
rated, monounsaturated, and diunsaturated components, which 
then were assayed for radioactivity. 
Results 
The retention times of all peaks present in the GC profile of 
cuticular hydrocarbons from R. virginicus (Fig. 1) match those from 
the GC profile of the cuticular hydrocarbons of P. howardi (Fig. 2), 
T. depressus (Fig. 3), and X. hexagonalis (Fig. 4). Confirmation of 
the chemical identity for each of the hydrocarbon components in 
most of the GC peaks was obtained by El and Cl mass spectrometry 
(MS). In every instance, the GC-MS retention times and mass spec- 
tra of the beetle hydrocarbon components were identical to those 
