1984] 
Wheeler — Behavior of Procryptocerus 
173 
every 2 minutes. Therefore, if an act lasted 30 minutes, it would be 
recorded 15 times. 
Most of the periods of observation fell between 0900 and 2300, 
but ants were also watched at 0200, 0400, and 0600. The colony was 
exposed to light from dawn (0500) until room lights were turned off 
(2100-0200). Under these conditions, the colony was arrhythmic; no 
regular differences in activity levels or types of behaviors were 
noted. Pupal to adult molts took place at different times of day and 
night. Molting is strictly tied to the biological clock in many insects, 
and the fact the molting was irregular suggests that the colony was 
physiologically, as well as behaviorally, arrhythmic. 
The behavioral repertoire was analyzed using a FORTRAN pro- 
gram written by R. Fagen for catalogue analysis using a log normal 
fitting procedure developed by Bulmer ( 1974) (Fagen and Goldman, 
1977; Fagen, 1978). 
Colonies of Zacryptocerus minutus and Z. christopherseni y were 
collected in central Panama. Various observations are reported here 
for comparison with the biology of P. scabriusculus. 
RESULTS 
CHA RA CTERIZA TION OF THE FEMA LE CASTES 
Two characteristics of the genus Procryptocerus are that the 
worker caste is monomorphic and that queens are slightly larger but 
very similar to workers (Kempf, 1951). The 2 female castes are 
compared graphically in Figure 1, in which head width is plotted 
against thoracic width. The size range of workers is so narrow that 
this caste can be considered monomorphic. Head widths of P. sca- 
briusculus workers ranged from 1 . 14-1 .36 mm, a difference of only 
0.22 mm. This is trivial in comparison to Z. minutus (0.96-1 .7 mm) 
and Z. christopherseni (1.42-2.66 mm), 2 species with distinct sol- 
diers. In C. atratus workers, head width across the occipital spines 
ranged from about 2-4.5 mm (Corn, 1980). 
Queens are morphologically similar to workers, but can be distin- 
guished from workers on the basis of a variety of quantitative as 
well as discrete differences. As shown in Fig. 1, queens can be dis- 
tinguished from workers on the basis of thoracic width. Other char- 
acters that are caste-specific are abdomen width and length, thoracic 
morphology, including wing scars, and the presence of ocelli. 
