Young Larvae of Eciton (Hymenoptera: Formicidae: Dorylinae)

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 complication. 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, Camponotus) 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. burchelli 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