1968] 
' Hermann and Blum — Camponotus 
217 
Much of the literature concerning the hymenopterous poison 
apparatus has been cited by Hermann and Blum (1966, 1967a, 
1967b). One of the first comparative investigations on the hymen- 
opterous poison apparatus that included descriptions on the apparatus 
of formieine ants was undertaken by Forel (1878). Since that time, 
Foerster (1912) contributed considerably to an understanding of the 
formieine poison apparatus, his work involving the skeletal and 
muscular components to describe a functional system. 
Emery (1922) and Buren (1944) noted that the nozzle-like pro- 
jection at the tip of the gaster of formieine ants is distinct from the 
cloacal orifice. As reviewed by Brown (1954), this projection forms 
a cone by an inrolling of the posterior portion of sternum VII and 
functions as a channel through which venom is sprayed to a con- 
siderable distance. This cone often has been misidentified as the 
cloacal orifice. 
Hung and Brown (1966) dealt in detail with this nozzle-like 
structure in the Formicinae, calling it the acidopore. It was pointed 
out that the ring of fine setae surrounding the acidopore, the coronula, 
directs the venom spray outward away from the ant’s body. The 
acidopore is situated on the ventral apex of sternum VII. In certain 
species of the Camponotini, the acidopore may be formed as much 
by tergum VII as by sternum VII. 
Carthy (1951), Wilson (1963) and Blum and Wilson (1964) 
reported that the odor trail pheromone in certain formieine species 
was a product of the hindgut or some structure associated with the 
hindgut. Knowledge of this source of pheromone distinguishes this 
subfamily from some other subfamilies of ants in which the trail 
pheromone is a product of the poison gland (Blum and Moser, 1963; 
Blum et al., 1964), Dufour’s gland (Wilson, 1959, 1962) or Pavan’s 
gland (Wilson and Pavan, 1959). 
Further anatomical investigations of the formieine poison apparatus 
were reported by Maschwitz (1964). In his work, Maschwitz de- 
scribed the poison sac and associated structures, Dufour’s gland and 
the method of venom ejection in certain formieine species. 
We undertook the present investigation in part to describe, the soft 
and sclerotized regions that make up the poison apparatus in Cam- 
ponotus pennsylvanicus (DeGeer). In an effort to characterize 
chemically the venoms of higher formieine ants, we undertook to 
identify the minor constituents that accompany formic acid in the 
venom of this species. At this juncture, we concentrated our efforts 
on establishing the chemical nature of the compounds secreted by 
the true poison gland in contradistinction to any components that may 
