GENERA
Figure A Pterotermes occidentis, the largest and most
primitive dry-wood termite in North America. Its colonies
are limited to the Sonoran Desert of southern Arizona,
southeastern California, and Sonora, Mexico. The swollen
abdomen of this pseudergate (worker) covers the large hindgut,
which harbors millions of microorganisms responsible for the
digestion of wood. SEM, bar 0.5 mm.