appearance in a definite manner in the course of the larval life. The caterpillar of Euchloe cardamines exhibits a larval metamorphosis of a well-marked character. The young larva (Fig. 181) is armed with peculiar setae, furcate at the tip, each of which bears a tiny

are present, and the FIG. 182.-Larva of Euchloe cardamines in middle life. A, the larva in profile; B, one segment more magnified. fluid-bearing spines nearly disappear, being reduced to a single series of spines of a comparatively small size on each side of the upper middle region of the body (Fig. 182). The colour is also a good deal changed, and concomitantly there is a much greater voracity and restlessness.

Fam. 5. Papilionidae.—All the legs well developed. Claws large, simple, without empodium. Front tibiae with a pad. The metanotum free, conspicuously exposed between mesonotum and abdomen. This series of butterflies includes some of the most magnificent of the members of the Insect world. It is considered by some authorities to be the highest family of butterflies; and in one very important feature-sexual differentiation-it certainly is entitled to the rank. There are about 700 recorded species, the larger portion of which are included in the genus Papilio. The great variety of form has led to this genus being divided; the attempts have, however, been partial, with the exception of an arrangement made by Felder, who adopted 75 sections, and a recent consideration of the subject by Haase, who arranges Felder's sections into three sub-genera. Many of the sections have received names, and are treated by some authors as genera, so that an unfortunate diversity exists as to the names used for these much-admired Insects. The genus is distributed all over the world, but is perhaps nowhere more numerous in species than in South America. Wallace informs us that the great

majority of the species of the Amazon valley frequent the shady groves of the virgin forest. In many cases the sexes are extremely different in appearance and habits, and are but rarely found together in one spot. The genus Ornithoptera is closely

allied to Papilio, and contains some of the most remarkable of butterflies, the homes of the species being the islands of the Malay Archipelago, and outlying groups of islands, there being a smaller number of species in the neighbouring continents. The females are of great size, and are so excessively different from their

consorts of the other sex, as to arouse in the student a feeling of surprise, and a strong desire to fathom the mysteries involved. It would be difficult to surpass the effective coloration of the males in many of the species of Ornithoptera; they are, too, very diverse in this respect; 0. brookiana is of an intense black colour, with a band of angular green marks extending the whole length of its wings, while behind the head there is a broad collar of crimson colour. Perhaps the most remarkable of all is the O. paradisea, recently discovered in New Guinea; in this species the sexual disparity reaches its maximum. The female (Fig. 184) is a large, sombre creature of black, white and grey colours, but the male (Fig. 183) is brilliant with gold and green, and is made additionally remarkable by a long tail of unusual form on each hind wing.

We may anticipate that these extraordinary cases of sexual total dissimilarity in appearance are accompanied by equally remarkable habits and physiological phenomena. In the case of O. brookiana the female is extremely rare, so that the collector, Künstler, could only obtain fifteen females to a thousand males. According to Mr. Skertchly, instead of the crowd of males being eager to compete for the females, the reverse is the case; the female diligently woos the male, who exhibits a reluctance to coupling. This observer apparently considered that the "emerald feathers" of the male are a guide or incitement to the female.1

of

In Africa Ornithoptera is to a certain extent represented by two extremely remarkable forms, Papilio zalmoris and P. (Drurya) antimachus. There are about a dozen other genera Papilionidae; most of them contain but few species. Parnassius, however, is rich in species inhabiting the mountains and elevated plateaus of the northern hemisphere in both the Old and New Worlds; it is remarkable for the small amount of scales on the wings, and for the numerous variations of the species. The female possesses a peculiar pouch at the end of the body; although only formed during the process of coupling, it has a special and characteristic form in most of the species. The curious Indian genus Leptocireus has parts of the front wings transparent, while the hind pair form long tails. This genus is of interest in that

We trust there will not be many more

1 Ann. Nat. Hist. (6), iv. 1889, p. 213. Künstlers, as this beautiful butterfly must certainly become extinct, if the female

be really as rare as is supposed.

it is said to connect Papilionidae to some extent with Hesperiidae. The larvae of this family are remarkable on account of a curious process on the thoracic segment called an "osmeterium." It is usually retracted, but at the will of the caterpillar can be everted in the form of a long furcate or Y-shaped process; there is a gland in the osmeterium, and as a result a strong odour is emitted when the exstulpation occurs.

The pupation of Papilionidae is similar to that of Pieridae, the pupa being placed with the head upwards, fixed by the tail, and girt round the middle. A very curious diversity of pupation occurs in the genus Thais, in which the pupa is attached by the tail as usual, and-which is quite exceptional-also by a thread placed at the top of the head. Scudder thinks there is also a girdle round the middle, but Dr. Chapman inclines to the view that the thread attaching the head is really the median girdle slipped upwards. The pupation of Parnassius is exceptional, inasmuch as, like Satyrides, it is terrestrial, in a slight construction of silk.

Fam. 6. Hesperiidae (Skippers).—Six perfect legs: metanotum not free, largely covered by the mesonotum. A pad on the front tibia. Claws short and thick; empodium present. Although this family has been comparatively neglected by entomologists, upwards of 2000 species and more than 200 genera are known, and it is not improbable that it may prove to be as extensive as Nymphalidae. We have already said that Hesperiidae is generally admitted to be the most distinct of the butterfly groups. It has been thought by some taxonomists to be allied to Papilionidae, but this is a mistake. It is undoubtedly more nearly allied to Heterocera, and when the classification of Lepidoptera is more advanced, so that the various natural groups placed in that sub-Order are satisfactorily distinguished, it is probable that Hesperiidae will be altogether separated from Rhopalocera. We have already mentioned that E. Reuter considers the Hesperiidae to be phylogenetically unconnected with Rhopalocera proper; but though quite ready to admit that he will probably prove correct in this, we think Lepidopterists will not be willing to recognise the family as a sub-Order equivalent in value to all Heterocera.

The body is shorter and thicker than it is in most butterflies, and is pointed at the tip rather than knobbed or bent downwards; the wings are less ample; the antennae are not truly