1935] 
Larva of Allomerus 
95 
curved ventrally (PL VIII, Fig. 2) . Type III hairs : A single 
pair of simple, slender, strongly curved hairs about 0.15 mm. 
long, at the anterior end, one a short distance in front of 
each mesothoracic spiracle (PL VIII, Fig. 1). Type IV 
hairs: A few very minute (0.009 mm. long), simple, 
straight, acute hairs on the prothorax around the base of 
the head (PL VIII, Fig. 3). 
Head and mouth-parts like those of worker larva. 
The above descriptions are based on larvae from a single 
nest collected at Kartabo, British Guiana, VII-27-1920. I am 
indebted to Dr. W. M. Wheeler for the material. 
Fig. 1. Allomerus octoarticulatus var. demerarae W. M. Wheeler. 
Larva ready to molt to definitive sexual form; the hairs of the latter 
are easily seen through the transparent integument of the younger 
form. Ventral view. X50. 
As mentioned previously the mature larvae of worker and 
sexual forms are so very different that they might be re- 
garded at first glance as belonging to different genera. That 
such is not the case is proved by the fact that the heads of 
the two types are identical and by the fact that I have found 
young larvae of the sexual type still encased in an integument 
of the worker type (Fig. 1). Moreover, a worker semipupa 
enclosed in an integument of the worker type (PL VII, Fig. 
3) shows that worker larvae do not attain what I have desig- 
nated as the definitive sexual form before pupating. 
In spite of the fact that all larvae of Allomerus are alike 
in the early instars, nevertheless, some slight differentiation 
occurs previous to the molt to the definitive sexual form. 
Such, at least, is my tentative interpretation of the material 
studied. The bodies of small (i. e. worker) semipupae are 
