The Cossidae are a small family of large moths (figs. 8, 18, 19) belonging to this section, characterized by their heads with erect rough scales or hairs, the pectinate feelers of the males, their reduced maxillae so that no food is taken in the perfect state, and their wings with the fifth radial nervure arising from the third, and the main median nervure forking in the discoidal areolet. The larvae feed in plant stems, often in the wood of trees, forming tunnels and galleries, and usually taking a year or more to reach maturity. The pupa which has three or four free segments in the male and four or five in the female, rests in a cocoon within the food plant, often strengthened by chips of wood, or in a subterranean cocoon. The family is fairly well represented in the tropics; the British fauna possesses only three species, of which the “goat” (Cossus cossus) and the “leopard” (Zeuzera pyrina) are well known, the caterpillars of both being often injurious to timber and fruit trees.
The Tortricidae are a large family of small moths (see fig. 1), nearly allied to the Cossidae. The fifth radial nervure does not arise from the third, the maxillae are well developed, but their palps are obsolete; the head is densely clothed with erect scales; the terminal segment of the labial palp is short and obtuse. The female pupa has three, the male four, free segments. All the larvae of these moths have some method of concealing themselves while feeding. A frequent plan is to roll up a leaf of the food-plant, fastening the twisted portion with silken threads so as to make a tubular retreat; this is the habit of the caterpillar of the green bell moth (Tortrix viridana) which often ravages the foliage of oak plantations. The larvae of the pine-shoot moths (Retinia) shelter in solidified resinous exudations from their coniferous food-plants, while the codlin-moth caterpillar (Carpocapsa pomonella) feeds in apples and pears, growing with the growth of the fruit which affords them both provender and home. The antics of “jumping-beans” are due to the movements of tortricid caterpillars within the substance of the seed.
The Psychidae are a small but widely-distributed family of moths whose males have the head, densely clothed with rough hairs, bearing complex, bipectinated feelers, but with the maxillae reduced and useless. The larvae live in portable cases made of grass, pieces of leaf or stick, with a silken lining, and these cases serve as cocoons for the pupae which agree in structure with those of the Tortricidae. But the most remarkable feature of the family is the extreme degradation of the female, which, wingless, legless and without jaws or feelers, never emerges from the cocoon.
| Fig. 20.—Castnia acraeoides. Brazil. | Fig. 21.—Neurosymploca concinna. S. Africa. |
The Castniidae are a small family of large, conspicuous, day-flying exotic moths (fig. 20) whose clubbed feelers and bright colours give them a resemblance to butterflies, although their wing-neuration is of the primitive tineoid type; the smooth larvae feed on the stems or roots of plants and the pupal structure agrees with that of the Tortricidae and Psychidae. The distribution of the family is confined to Tropical America and the Indo-Malayan and Australian regions.
| Fig. 22.—A, Sesia asiliformis (Gad-fly Hawk Moth). Europe. B, Larva. |
The Zygaenidae (burnet moths) are a large family of day-flying moths (fig. 21) adorned with brilliant metallic colours. The feelers are long, stout in the middle and tapering, bearing numerous long or short pectinations. The well-developed maxillae have vestigial palps. The larvae—often very conspicuously coloured—are remarkable among the Tineides in having incomplete circles of hooks on the prolegs, and they feed exposed on the leaves of various plants. The pupa, enclosed in a silken cocoon, has four or five free segments. The Limacodidae are a small family of brownish nocturnal moths, allied to the Zygaenidae and agreeing with them in the structure of the pupa. The larva in this family also is an exposed feeder, but it is remarkable in form, being flattened and slug-like, without prolegs and adorned with curious spinous processes.
The Sesiidae are a large family of small, narrow-winged moths, the sub-costal nervure of the hindwing being absent and the wings being for the most part destitute of scales (fig. 22). The maxillae are developed but their palps are vestigial, while the terminal segment of the labial palp is short and pointed. Many of these insects have their bodies banded with black and yellow; this in conjunction with the transparent wings makes some of them like wasps or hornets in appearance. The larvae feed in the woody stems of various plants. The pupa, with three or four free abdominal segments, remains within its cocoon, formed with chips of wood, until the time for its final change draws near; then it works itself partly out of the tree by means of the spines on its abdominal segments.
The Nepticulidae are the smallest of all the Lepidoptera, measuring only 3-8 mm. across the outspread wings, which are all lanceolate and pointed at the tip. The sucking portions of the maxillae are vestigial, but the palps are long and jointed. The larvae, without 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.
| Fig. 23.—Adela degeerella. Europe. | Fig. 24.—Euplocampus anthracinus. Europe. | Fig. 25.—Tinea tapetzella (Clothes Moth). Europe. |