1963] Blum and Callahan — Glands of Pseudomyrmex 
7i 
the fire ant the valve is inserted forward on the lancet body (See 
Fig. 8. Callahan et al. 1959) and the ramus makes more of a curve 
where it joins the lancet. Secondly, unlike the fire ant, the tip of the 
lancet of Pseudomyrmex pallidas is not barbed. 
The Venom 
The venom of P. pallidas was obtained by holding the isolated 
abdomen of the ant by the petiole and collecting the venom issuing 
from the everted sting in microcapillaries or in the depression of a 
microscope slide. As many as twelve small droplets may be obtained 
by this method, after which the sting is invariably withdrawn, 
although the poison vesicle may still contain substantial quantities 
of venom. 
The venom is a water-clear liquid which consists of a single phase. 
On contact with the air, each droplet solidifies into clear plates which 
can be easily chipped off the glass. However, if the venom is collected 
directly in fine capillaries, it retains its fluidity. Examination of the 
poison gland and Dufour’s gland reveals that both contain water- 
clear liquids. The substance in the poison vesicle solidifies on contact 
with the air to form plates identical to those formed by the venom 
issuing from the sting. 
The solubility of the venom was determined by allowing it to issue 
while the tip of the sting was held under different liquids. The venom 
is insoluble in distilled water and forms opaque strands which suspend 
in the aqueous medium. In organic solvents such as methanol, chloro- 
form, rc-hexane and diethyl ether, the venom forms insoluble, clear 
plates similar to those obtained when it is exposed to air. The venom 
is very soluble in dilute acids. 
The venom is alkaline when tested with various indicator papers 
as an aqueous suspension. When the poison vesicle is crushed on 
indicator papers it also gives an alkaline reaction but interestingly, the 
viscous contents from crushed Dufour’s gland are neutral. The 
secretions of the two glands are further contrasted by the fact that 
the fluid in Dufour’s gland is soluble in organic solvents whereas the 
poison vesicle contents are not. 
The venom of P. pallidas is ninhydrin-positive, producing a dark 
purple coloration with this reagent. Paper chromatographic analysis 
of the venom did not reveal the presence of any free amino acids; the 
ninhydrin-positive material all remained at the origin. All these 
data are consistent with the conclusion that the venom of this pseudo- 
myrmicine ant is a basic protein (s). 
