Psyche 
[March 
156 
Table I. Size and Composition of Adult Populations of Stelopolybia 
areata colonies. 
Estimated 
Colony 
No. 
Date 
Collected 
No. Adults 
Collected 
No. Queens 
Collected 
Percent 
Queens 
Total Adult 
Population 
707 
2 Feb. 1973 
5884 
716 
12.2 
7000 
710 
15 Jan. 1973 
7950 
515 
6.1 
8500 
725 
23 Feb. 1973 
4711 
257 
5.5 
6000 
731 
21 Feb. 1973 
4227 
503 
11.8 
6000 
in Table I. A description of the nest of this species and notes on 
colony cycle are published elsewhere (Jeanne 1973). 
In a mass of anaesthetized adults, queens can readily be picked 
out by virtue of their larger size and distinctive morphology and 
coloration. Random dissections of queens and workers always showed 
that the former had well-developed ovaries and full spermathecae, 
while the latter had undeveloped ovaries and empty spermathecae. 
For the present study random samples of queens and workers from 
each colony were measured and compared. Length of alitrunk was 
chosen as a measure of body size. This was measured from the front 
of the humeral collar to the furthest posterior extension of the pro- 
podeal valves, as seen from the side. This dimension was preferred 
as a measure of body size for several reasons. First, the alitrunk is 
the longest rigid structure of the body, hence is not subject to error 
due to varying degrees of distension of the gut, or to differences in 
body position. Second, it is not likely to be an allometric growth 
center, unlike in the ants, since both queens and workers are winged. 
Any functional difference in use of wings by workers and queens is 
less likely to be reflected by allometric differences in size of the thorax 
than in differences in the wings themselves. Finally, it is preferred 
to wing length, used in other studies, because wings are subject to 
fraying at the tips in older workers, making them impossible to mea- 
sure, and thus biasing the sample against older workers. 
The most conspicuous morphologic difference between the two 
castes is the more bulbous first abdominal tergite (petiole) in the 
queens (Fig. 1). This is best reflected in its width at the widest 
point, as seen from above; hence this dimension was used as a measure 
of allometric growth. 
All measurements were made on specimens pinned while fresh 
using an ocular micrometer at a magnification of 25 X . 
