220 
Psyche 
[September 
The sac is surrounded by a simple muscular layer which functions 
in forcing venom out of the sac. The convoluted region receives an 
abundant tracheal supply. 
Dufour’s gland (DG) in C. pennsylvanicus differs markedly from 
those glands in other subfamilies of ants. Instead of being an elongate 
unilobular sac, as is commonly found in ants previously examined, 
Dufour’s gland in this species is bilobed (Fig. 2, C). A bilobed 
Dufour’s gland has been reported in Formica rufibarbis by Forel 
(1878) and in Formica polyctena by Maschwitz (1964). 
The components that make up the sclerotized portion of the poison 
apparatus (Fig. 1, D) are basically similar to those in stinging 
Hymenoptera (Fig. 1, A, B, C). However, some of the major 
sclerites have become reduced almost to a point beyond recognition. 
The oblong plate is relatively well developed (OP, Fig. 1, D; 
Fig. 2, FI). However, its ramus (Ra 2) has been reduced consider- 
ably, so that now it is represented by a thin and slightly sclerotized 
bar only near the proximal end of the oblong plate. The fused 
second valvulae (sting) are wanting. Consequently, the levator 
muscle of the sting, normally originating on the posterior border of 
the second ramus and inserting on the anterior region of the sting 
bulb (SB, Fig. 2, G), is also wanting. 
Although gonostyli are present (Go, Fig. 1, D; Fig. 2, I), they 
are membranous and possess minute setae (Set) along the lateral and 
ventrolateral regions. Most stinging Hymenoptera possess long setae 
on each gonostylus (Fig. 1, A), especially in the caudal and ventro- 
caudal region. 
The first valvifers (triangular plates, TP, Fig. 1, D; Fig. 2, E) 
are triangular in appearance, and each articulates anteriorly to a 
slender ramus (Ra 1). In stinging Hymenoptera, each of the rami 
articulates ventrally with an elongate lancet shaft (LS) the latter 
usually terminating distally as a pointed and barbed structure (Fig. 1, 
C). However, in C. pennsylvanicus each first valvifer is no longer 
a lancet shaft, but an elongate rod that terminates in a spatulate 
distal end (Fig. 1, D; Fig. 2, E). The valve, a structure that 
Fig. 2. Components of the poison apparatus of C. pennsylvanicus and a 
stinging ant species (LV). A-Transverse section of poison sac. B-Poison 
sac of C. pennsylvanicus (DV). C-Dufour’s gland of C. pennsylvanicus 
(DV). D-Lancet of Paraponera clavata (LV). E-Lancet of C. pennsyl- 
vanicus (LV). F-Spiracular plate of C. pennsylvanicus (LV). G-Oblong 
plate, second ramus, gonostylus, fulcral arm and sting of P. clavata (LV). 
H-Oblong plate, gonostylus and portion of second ramus of C. pennsylvanicus 
(LV). I-Gonostylus of C. pennsylvanicus (LV). 
