A characteristic, comparable in value to that presented by the pygidial shield of Arachnida, is the frequent development of a pair of long appendages by the penultimate somite, which with the telson form a trifid, or, when that is small, a bifid termination to the body.
Cephalic shield bifid posteriorly; margins of foot slightly developed; genital duct diaulic; visceral cornmissure streptoneur ous; shell thick, with prominent spire and elongated aperture; a horny operculum.
They may be characterized as very elongated reptiles without limbs (unless with tiny vestiges of posterior limbs), without eyelids and external ear openings, with the teeth anchylosed to the supporting bones, a bifid slender tongue which is telescoped into its basal half, and with a transverse vent.
Among the common characters may be noted the possession of: (i) pectoral mammae; (2) abdominal testes; (3) a bifid apex of the heart; (4) bilophodont molars with a tendency to the formation of an additional lobe from the posterior part of the cingulum.
The setae are either entirely capillary or there are in addition some sigmoid setae even with bifid free extremities.
The tongue is bifid at the tip in a few genera; usually it is pointed and varies greatly in length, being comparatively short in Andrena, long in the humble-bees(Bombus), and longest in Euglossa, a tropical American genus of solitary bees.
The tongue is villose, smooth, bifid anteriorly.
From the tubular portion below, the bifid style projects slightly.
Always bifid and re tractile into itself.
The intestinal sac has become bifid and is usually devoid of branches.