LIBRARY

424
COLLEGE ENTOMOLOGY
edible one, (2) Mullerian mimicry in which two or more distasteful species
mimic each other so that the benefits formerly held by each might be more
or less evenly enjoyed by all the members of both. Both of these types may
be classed as purposeful mimicry. Other types which are difficult to define
in so small a space also occur in nature.
Eggs - among the marvels of biology because of their innumerable sizes,
shapes, sculpturings, colors, designs, and arrangements. Usually with tough,
hard shells. Form - spherical, subglobular, flattened or disk-like, conical,
hemispherical, cylindrical, ovoid, fusiform, barrel-shaped, angular, and
innumerable other types. Surface - smooth and shining or variously traced
and sculptured; ribbed, striated, punctured, reticulated, tuberculate, and
otherwise ornamented. Covering - sometimes covered with silk, cement, and
hairs from the body of the female or deposited within a matrix of cement
which serves to protect them through the winter. Colors - green, white, and
yellow predominating, but also brown, red, blue, purple, and various combinations;
sometimes brilliant and metallic; more often cryptic or spotted.
Micropyle, or microscopic opening for the entrance of the sperm - present.
In some species a lid is formed which is pushed off by the emerging caterpillar.
Laid - singly, scattered, in rows, regular, or irregular masses, short
suspended chains, in matrices of cement, and in other ways; usually attached
to the host but may be deposited indiscriminately by some species in the
vicinity of the host.
EXTERNAL ANATOMY - LARV)E
Size - minute, from 3-5 mm. up to the large sphinx caterpillars, 130-150 mm.
in length. Others may be shorter, more robust, and therefore bulkier and
heavier.
Shape - usually elongate-cylindrical, slender or robust; some very short and
oval; leaf miners decidedly flattened and elongated. Certain forms resemble
twigs to a remarkable degree.
Colors - predominately green or otherwise cryptic; many are brightly ornamented
and may have a wide variety of patterns and unique designs. Some
pass through a series of color patterns and others have different color phases.
Surfa.ce Md vestiture - very many are naked, smooth or wrinkled, and with
indistinct setre; others are hairy and spiny, some having compound spines
(verruc.:e and scoli) in a wide variety of arrangements; hairs and spines often
stinging and nettle-like; naked or spined tubercules and processes may also
be present. Hollow poisonous glandular hairs occur in a few species.
Integument - thin, elastic, sometimes very delicate, or tough, leathery and
partly chitinized; composed of head, three thoracic. and 13 body segments.
Head - usually hypognathous; prominent; hard, chitinous, smooth or with
horn-like projections; globular, conical, hemispherical, bilobed; free and
readily mobile; with ad frontal areas (narrow sc1erites along the epicranial
suture).