Page:EB1911 - Volume 16.djvu/492

Rh thoracic limbs or prolegs, but sometimes with paired rudimentary processes on some of the segments, mine in the leaves of plants. The pupa, with four free abdominal segments in the female and five in the male, rests in a cocoon usually outside the mine.

The Adelidae are a family of delicate, but larger, moths with very long feelers (fig. 23) especially in the males. The larvae feed, when young, in flowers; later, protected by a flat case, they devour leaves; the pupa resembles that of the Nepticulidae in structure. The female has an ovipositor adapted for piercing plant tissues.

The Tineidae are a large and important family of small moths (figs. 14, 24, 25) with rough-haired heads, and with the maxillae and their palps usually well developed. Many of the genera have narrow pointed wings with degraded neuration. The larvae differ in their habits, some—Gracilaria for example—mine in leaves, while others, like the well-known caterpillars of the clothes moth (Tinea) surround themselves with portable cases (fig. 14) formed by spinning together their own excrement. The female pupa has three, the male four free abdominal segments.

This group includes a few large families of small moths that are linked by their imaginal and larval structure to the Tineidae (in which they have often been included) and by their pupal structure to the higher groups that have yet to be considered. The moths have labial palps with slender pointed terminal segments, and narrow pointed wings, but the neuration (except in the Elachistidae) is less degenerate than in most Tineidae. The hairy covering of the head is smooth, and the maxillary palps are usually vestigial. The egg is flat, and the larval prolegs have complete circles of hooklets. The pupa is obtect with only two free abdominal segments (fifth and sixth) in both sexes and does not move out of the cocoon.

Four families are included in this group. The Plutellidae (fig. 26) have the maxillary palps developed, in some genera, as slender threadlike appendages directed straight forward. The larvae do not usually mine in leaves, but feed openly, keeping to the underside for protection (Plutella), or spinning by their united labour a mass of web over the food-plant (Hyponomeuta). In the other three families the maxillary palps are vestigial or obsolete. The Elachistidae have remarkably narrow, pointed wings and their larvae mine in leaves or form portable cases and feed among seeds. In the Oecophoridae (fig. 27) the sub-costal nervure of the hindwing is free and distinct throughout its length, and the larvae usually feed among spun leaves or seeds, or in decayed wood. The Gelechiidae are a large family with similar larval habits; the moths are distinguished by the sinuate termen of the hindwing and the connexion of its sub-costal nervure with the discoidal areolet.

This group includes a number of moths of delicate build with elongate legs, the maxillae and their palps being usually well developed. The forewings have two anal nervures, the hindwings three (fig. 30, h, i); in the hindwing the sub-costal nervure bends towards and often connects with the radial, and the frenulum is usually present. The egg is flat. The larva has complete circles of hooklets on its five pairs of prolegs, and the pupa (usually completely obtect) does not move at all from its cocoon. This group includes the only Lepidoptera that have aquatic larvae.

Of the families comprised in this division three deserve special mention. The Pterophoridae (plume moths, fig. 28) usually have the wings deeply cleft—a single cleft in the forewing and two in the hindwing. The hairy larvae feed openly on leaves, while the soft and hairy pupa remains attached to its cocoon by the cremaster, although it is incompletely obtect and has three or four free abdominal segments. The Orneodidae (multiplume moths) have all the wings six-cleft. Our British species, Orneodes hexadactyla (fig. 29), is an exquisite little insect, whose larva feeds on the blossoms of honeysuckle. The pupa is completely obtect, with only two free abdominal segments. The Pyralidae (figs. 13, 30), a large family with numerous divisions, have entire wings, and their pupae are obtect. The caterpillars feed in some kind of shelter, some spinning a loose case among the leaves of their food-plant, others burrowing into dry vegetable substances or eating the waxen cells of bees. Several species of this group, such as the Mediterranean flour moth, Ephestia kühniella (fig. 30), become serious pests in storehouses and granaries, their larvae devouring flour and similar food-stuffs.

In this group may be included a number of families of moths with the second median nervure of the forewing arising close to the third. This feature of neuration characterizes also the Jugatae (see fig. 6), Tineides, Plutellides and Pyralides. But the Noctuides differ from these groups in having only two anal nervures in the hindwing. The maxillary palps are absent or vestigial, and a frenulum is usually present on the hindwing. The larva has usually ten prolegs, whose hooklets are arranged only along the inner edge, while the immobile pupa is always obtect with only two free abdominal segments (the fifth and sixth). The Lasiocampidae and their allies have flat eggs, but in the Noctuidae, Arctiidae and their allies the egg is upright.

The Lasiocampidae, together with a few small families, differ from the majority of this group in wanting a frenulum. The maxillae of the Lasiocampidae are so reduced that no food is taken in the imaginal state, and in correlation with this condition the feelers of the male are strongly (those of the female more feebly) bipectinated. The moths are stout, hairy insects, usually brown or yellow in the pattern of their wings. The caterpillars are densely hairy and many species hibernate in the larval stage. The pupa is enclosed in a hard, dense cocoon, whence the name “eggars” is often applied to the family, which has a wide distribution, but is absent from New Zealand. The Drepanulidae are an allied family, in which the frenulum is usually present, while the hindmost pair of larval prolegs are absent, their segment being prolonged into a pointed process which is raised up when the caterpillar is at rest. The hook-tip moths represent this family in the British fauna.

The Lymantriidae resemble the Lasiocampidae in their hairy bodies ana vestigial maxillae, but the frenulum is usually present on the hindwing and the feelers are bipectinate only in the males. Some females of this family—the vapourer moths (Orgyia and allies, fig. 17), for example—are degenerate creatures with vestigial wings. The larvae (fig. 15) are very hairy, and often carry dense tufts on some of their segments; hence the name of “tussocks” frequently applied to them. The pupae are also often hairy (fig. 16)—an 