72 
Psyche 
[March 
The basal half of the convoluted gland is chiefly composed of ducts 
lined with squamous cells and a strongly refringent intima (Med, 
Fig. 2 E). We have termed this region the medulla since it clearly 
functions in the collection of venom synthesized in the filaments and 
distal convoluted gland. The strongly developed intima probably is 
necessary for the protection of the remaining cellular components 
that link the convoluted gland with the reservoir. Formic acid is 
the chief constituent of formicine venom. The basal ducts in the 
medulla have an increasingly large lumen. Adnate to the venom sac 
a large supply of venom collects to flow into the reservoir. There 
appears to be no control of the venom flow from the medulla duct to 
the reservoir. No valves, dilator or occlusor muscles could be found. 
Based on an examination of the venom components in most of the 
other formicid subfamilies, it appears that the venom components of 
hymenopterous insects other than the Formicinae have a similar com- 
position cellularly, regardless of the arrangement between the glandu- 
lar and reservoir regions. The convoluted gland in non-formicine 
hymenopterans is inside the reservoir. However, the basic connections 
between reservoir, convoluted gland and filamentous glands are sim- 
ilar; the venom components of all hymenopterans have been modified 
from a simple invagination of the integument. 
Since fatty tissue functions in the storage of a diverse array of 
compounds and it is the site for intermediary metabolism, it is rea- 
sonable to assume that venom synthesis begins at this point. The 
filamentous glands, being closely associated with the fat, pick up 
venom precursors and change them considerably before they get to the 
convoluted gland. Venom synthesis is completed in the distal region 
of the convoluted gland, the proximal portion functioning only in 
the collection of venom and the transportation of it to the venom 
reservoir. 
Summary 
The cells of the filaments, convoluted gland and venom reservoir 
vary considerably. The filaments are more glandular in function than 
previously expected. The convoluted gland clearly is part glandular 
(cortex) and part collecting duct (medulla). The movement of 
venom from the medullar region of the convoluted gland is unaided 
by a special release mechanism. In its release from the venom reser- 
voir, venom is forced out through the acidopore by circular muscles 
most abundantly found near the base of the reservoir. 
