YOUNG LARVAE OF ECITON 
(HYMENOPTERA: FORMICIDAE: DORYLINAE) 1 
By George C. Wheeler and Jeanette Wheeler 
3358 NE 58th Avenue, 
Silver Springs, Florida 32688 
I. Instars 
In our previous studies of ant larvae we have been concerned 
primarily with generic characterizations and differences based on 
mature larvae. We described immature stages when available, which 
wasn’t often. And even when we did, we didn’t know the instars. 
Never have we had a complete larval series from egg to semipupa. 
Yet many authors have stated quite glibly the number of larval 
instars. At least it seems glib to us, for we consider it hard work to 
establish the number of instars. To do this we require that following 
specimens: a first-instar larva inside an egg ready to hatch; a second 
instar larva inside a first ready to moult; a third-instar inside a 
second-instar ready to moult; etc.; and finally a mature larva. How 
can we prove maturity? By comparison with a semipupa, which will 
reveal all characters of a mature larvae except shape. For further 
confirmation one should have a worker pupa or a worker to verify 
size. The identification of sexual larvae presents a further complica- 
tion. If the larva is larger than a worker semipupa it is probably a 
sexual or at least a queen. In most species we have not been able to 
recognize younger sexual larvae. 
In polymorphic species (e.g., Eciton, Atta, Acromyrmex, Cam- 
ponotus) such procedures are even more difficult. How can one tell 
whether a small larva is a young major or a mature minum or 
whether a large larva is a half-grown major or a mature intermediate? 
Two interesting papers afford a partial solution to this problem: 
Tafuri (1955) on Eciton hamatum and Lappano (1958) on E. bur- 
chelli 
Eciton is an ideal genus for such a study: there can be no mixing 
of broods; except for one all-sexual brood per year, all larvae will 
1 Manuscript received by the editor June 30, 1986. 
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