4) with serrate processes, projecting from the ventral surface of the abdomen between the eighth and ninth segments.
Sharp; in the stag-beetle larva a series of short tubercles on the hind-leg is drawn across the serrate edge of a plate on the haunch of the intermediate legs, while in the Passalid grub the modified tip of the hind-leg acts as a scraper, being so shortened that it is useless for locomotion, but highly specialized for producing sound.
Elaboration in the form of the feelers, often a secondary sexual character in male insects, may result from a distal broadening of the segments, so that the appendage becomes serrate, or from the development of processes bearing sensory organs, so that the structure is pinnate or feather-like.
- a, Bed-bug (Cimex lectularius, Linn.); newly hatched young from beneath; b, from above; d, egg, magnified 25 times; c, foot with claws; e, serrate spine, more highly magnified.
Most saw-fly larvae devour leaves, and the beautifully serrate processes of the ovipositor are well adapted for egg-laying in plant tissues.
They are as a rule of a very hardy character, thriving best in northern latitudes - the trees having round, slender branches, and serrate, deciduous leaves, with barren and fertile catkins on the same tree, and winged fruits, the so-called seeds.
Epidermal appendages are rare, the most frequent being marginal, saw-like, cartilaginous teeth, usually minute, but occasionally (Danthonia scabra, Panicum serratum) so large as to give the margin a serrate appearance.