1936] 
Crematogaster from Guatemala 
41 
black. The male of the latter also differs from the male 
sumichrasti in having the thorax and pedicel ivory white, 
instead of yellow and the head and gaster more deeply infus- 
cated, and both the male and the female are completely 
apterous , even in the pupal stage , instead of possessing well- 
developed wings like sumichrasti. Many years ago (1884), 
Forel described the worker and female (presumably winged 
or dealated) of a form of sumichrasti collected by Stoll at 
Antigua, Guatemala, as subsp. surdior. Two worker cotypes 
of this ant in my collection show that the body is pale red- 
dish castaneous and hence intermediate in color between the 
typical sumichrasti and the form from Lake Atitlan. Yet 
the aptery of both sexual castes of the latter, a condition 
unique among all known Formicidse, suggests two prob- 
lems, one involving the interpretation of the constitution 
of the colony as a whole, the other purely taxonomic. In 
other words, we are led to inquire whether the personnel of 
each of the colonies which I collected consists of a single 
independent, or of two different species, living in host and 
parasite relation. Either a positive or a negative answer 
to this question necessarily implies the further question as 
to the taxonomic status of the Atitlan specimens. 
That we are dealing with only a single form in each of 
the two colonies is indicated by the following considera- 
tions: — 
(1) Apart from coloration, which can have only varietal 
significance, and the aptery of the two sexual castes, which 
to the taxonomist is a more important character, there is 
very little to distinguish the Atitlan form from sumichrasti, 
(2) The darker color of the worker and female and the 
aptery of both sexual castes might be interpreted as muta- 
tions that have survived in a peculiar xerothermal environ- 
ment. This is suggested by the fact that the colonies were 
nesting in the ground in exposed situations, whereas all or 
nearly all the other known species of the subgenus Ortho- 
crema are forest ants which nest in plant-cavities. This is 
true even of the typical sumichrasti and its subsp. surdior. 
The type colony of the latter, according to Forel, was found 
attending aphids under the leaf-sheaths of a banana plant, 
and recently Dr. Skwarra (1934, p. 120) has recorded the 
