Agriculture Reference
In-Depth Information
Fig. 4 Examples of insect antennae: (a) clavate;
(b) filiform; (c) aristate; (d) geniculate; (e)
moniliform; (f) pectinate; (g) serrate.
doptera, the wings may be held together in flight
by a frenulum (a long bristle or long bristles
arising from the hindwing which interlock with a
retaining hook - the retinaculum - or a set of
small bristles on the underside of the forewing)
or by a jugum (a narrow lobe projecting from
near the base of the forewing).
The basic arrangement of veins in the wing
has undergone considerable modification in the
various insect orders, and details of wing vena-
tion often form the basis for distinguishing be-
tween groups and, sometimes, individual species.
The venation of a generalized wing is composed
of six main elements: costa (C), sub-costa (Sc),
radius (R), media (M), cubitus (Cu) and anal
(A). Wings of some insects also include a
pigmented patch (pterostigma), usually located
near the apex. Some wing veins may be fused or
absent, whereas others may be subdivided or dis-
tinctly forked. The radius, for example, often
branches to produce a curved radial section (Rs)
which may itself branch more than once before
Fig. 5 Segmentation of the leg of an insect, based on
the mid-leg of an adult chafer.
bees) a series of hooks (hamuli) on the leading
edge (costal margin or costa) of the hindwing
interlock with a fold in the trailing edge (dorsal
margin or dorsum) of the forewing; in Lepi-
