1958] Wilson , Durlach, Roth — Chemical Releasers 111 
of transporting them away from the nests, the workers 
began to lick and chew them vigorously. One was carried 
quickly into the nest ; the other two were dragged back and 
forth for short distances near the nest entrance. Several 
untreated corpses placed around the leached bodies were 
at the same time carried directly off to the refuse piles. 
One of the leached bodies was recovered several minutes 
after its introduction, daubed with corpse extract, and re- 
introduced. The same workers that had been licking it pre- 
viously now carried it directly to the refuse piles. The 
other two leached bodies were left in position to observe 
their subsequent treatment. One was dismembered by the 
living workers; both were carried away from the nests 
only after forty minutes or longer. 
The paper-square test described previously was next 
employed to test a few common fat and protein decomposi- 
tion products and related compounds obtained as chemical 
reagents. The following substances produced no detectable 
response, either in saturated or dilute solutions : ammonium 
sulfide, di-alpha-amine. Weak to moderate alarm behavior, 
followed occasionally by digging behavior x , was evoked 
by the following substances: phenylethylamine, triethano- 
lamine, phenol, n-valeric acid, n-caproic acid, n-caprylic 
acid, n-butyric acid, formic acid. The only substance tested 
that released the necrophoric response, or anything re- 
sembling it, was oleic acid. In repeated trials, oleic acid 
daubed onto paper squares and other small neutral objects 
invariably elicited a behavioral response from P. badius 
indistinguishable from that evoked by worker corpses. 
On the assumption that oleic acid, or a related compound, 
is a principal natural releaser of the necrophoric response, 
an attempt was made to separate and analyze the long- 
chain fatty acids found in Pogonomyrmex worker corpses. 
Infrared spectra were prepared from a crude extract of 
about 200 dead bodies of P. barbatus (Fr. Smith). These 
spectra were made from a sample in CC14 and from a 
liquid film after the carbon tetrachloride was evaporated. 
1 A fuller account of alarm and digging behavior, and of the various 
stimuli that release these linked responses, has been presented elsewhere 
(Wilson, 1959). 
