2 
Psyche 
[March 
It has now been possible to examine the glandular sources of the odor 
trail substances in four genera of the Attini and to determine their 
cross-specificities. The results of these studies are the subject of this 
paper. 
TEST SPECIES 
Based on morphology, behavior, and nest structure, Weber (1958) 
concludes that Cyphomyrmex rimosus (Spinola) is the most primitive 
of the attines. This species was selected as an ideal representative of 
the less specialized attine genera. Odor trail laying has not been noted 
in C. rimosus , which has been reported to forage singly. However, 
our own observations of the foraging behavior of workers from two 
colonies of this attine strongly indicate that this species lays odor trails. 
Both of the observed colonies were located in sandy soil at the base 
of trees ( Finns spp.) in Desoto National Forest near Gulfport, 
Mississippi. Each worker that emerged from the inconspicuous nest 
entrances moved slowly over the bark of the trees and made the same 
twists and turns as the workers that had preceded it. In two instances, 
pairs of workers emerged from the nest and moved with such com- 
plete synchrony that it seems very likely that odor trails were being 
followed. 
The other attines examined were Trachymyrmex septentrionalis 
(McCook) 5 , Acromyrmex octospinosus (Reich) 6 , and Atta cephalotes 
(Linnaeus) 6 . In addition, odor trail species specificity studies were 
undertaken employing A tta texana 1 . 
SOURCE OF TRAIL SUBSTANCES 
The sources of the odor trail substances were determined by using 
either a modification of the artificial trail technique of Wilson (1959) 
or the method of Moser and Blum (1963). For all species examined, 
preliminary experiments indicated that the odor trail substances orig- 
inated in the abdomen. Three organs in the abdomen, the hind gut, 
the paired poison glands and Dufour’s gland, are known to secrete 
their contents into the external environment. These organs were dis- 
sected out of workers, washed in saline, and applied as smears on 75 
cm. sinusoidal trails drawn on pieces of 8*4 " x 11" paper. 
The trail-treated papers were placed either on glass platforms 
adjacent to laboratory colonies or in metal trays. Groups of 10 ants 
from laboratory colonies were placed on the treated papers and a re- 
sponse was considered positive when a worker followed the trail to its 
“Collected at Baton Rouge, Louisiana. 
“Collected at Alajuela, Costa Rica. 
’Collected at Forest Hill, Louisiana. 
8 Collected at Barro Colorado, Canal Zone. 
