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[Vol. 93 
become workers. All one needs to determine, then, is whether the 
larvae in such a brood foreshadow adult polymorphism, and if so, 
how? The solution depends upon the fact that at the middle of the 
statary phase the queen lays during one week a single batch of 60,000 
to 130,000 eggs and then no more until the next statary phase. 
“In E. hamatum the adult polymorphic workers form a continu- 
ous series from the smallest worker minor to the largest soldier 
form. . .. Besides differences in size there are apparent qualitative 
differences in this series marked primarily by the exceptional 
hooked manidbles and head pattern of the major workers.” (Tafuri 
1955: 32.) In the larvae, however, such differences “are not noticea- 
bly apparent.” Any distinction of growth stages (i.e. nomadic days) 
is impossible on the basis of body size alone, because of overlap- 
ping. The larvae likewise form a smooth series from the smallest to 
the largest forms. The author therefore based his determination of 
larval age (in nomadic days) on the allelomorphic growth of the 
imaginal leg discs. 
“[It] is highly probable that the largest larvae of any stage have 
developed from the eggs first to be laid and first to hatch and 
represent the potential major workers of the mature brood. Sim- 
ilarly, the smallests [larvae] presumably develop from the eggs last 
to be laid and last to hatch and represent the potential workers 
minima of the mature brood.” (Lappano 1958: 49). 
From these two articles we get the impression that larval devel- 
opment in Eciton is a smooth process from hatching to pupation 
without any such interruptions as molts. The word “instar” is not 
found in either of these articles. 
So we re-examined our supply of doryline larvae and found 
graded series of larvae of Eciton hamatum sent to us by the late Dr. 
T. C. Schneirla (including some of the sample studied by Lappano) 
from Barro Colorado Island (Panama) and a similar supply of E. 
burchelli larvae collected in Trinidad by Dr. N. A. Weber. 
The great advantage of the Tafuri/ Lappano method is that it 
requires no technique and can be applied to either living or pre- 
served material. However, after applying our tedious technique 
(Wheeler and Wheeler 1960) of cleaning, staining and mounting in 
balsam, we found that we had the prerequisite for identifying all 
instars, except the mature larva, which we had already studied 
(Wheeler and Wheeler 1984). We should warn, however, that the 
