|Introduction
|Identification Key
|
Order Megaloptera
(Fishflies, Alderflies, and Dobsonflies)
The Megaloptera comprise a relatively small order; approximately 50 species are
found in North America (McCafferty 1981). The larvae of this holometabolous order
are the only life stage which is aquatic. Megalopteran larvae are predacious and
exhibit strong mandibles which can inflict a painful bite (when handling these
larvae be sure to hold them directly behind the head in order to prevent being
pinched). Dobsonflies and Fishflies (both Family Corydalidae) and Alderflies
(Family Sialidae) are all grossly similar in morphology, but can be distinguished
based on a few characteristics. The abdomen of both dobsonflies and fishflies
terminates in a pair of anal prolegs, each with two hooks, while the
abdomen of alderflies terminates in a single median filament without hooks. In
order to differentiate between fishflies and dobsonflies look at the ventral side
of the abdomen. Dobsonflies have cottony gill tufts beside the lateral appendages,
fishflies lack such gills. An example from
each family follows: