November 2, 189(5. 



KNOWLEDGE. 



245 



of their colours. Numerous species are reckoned withia 

 their number, many of large size, and generally adorned 

 with beautiful coloarj, a rich effect heightened by the 

 metallic gloss of the prominent scales with which most of 

 them are covered. In respect of colour the sexes may 

 differ widely. 



Turning to their preparatory stages, the larvie are 

 endophytous, boring, with strong mandibles, the interior 

 of stems and roots of cacti, of orchids, and other plants — • 

 a habit which, though found in butterflies, is very excep- 

 tional. Likewise, they are provided with the ordinary 

 horny piliferous spots or tubercles that characterize Hetero- 

 cerous larvit, and have a horny anal plate, whereas butter- 

 fly larv;f rarely possess these warts. In keeping with all 

 Heterocerous borers, the pupae are supplied with minute 

 spines on the hind borders of the abdominal joints, 

 affording the pupa power of moving in the tunnel bored 

 in the tree, and assisting it out of its coeoon. 



The Castniida: are essentially proper to the warm equa- 

 torial regions ; their geographical range, in fact, extends 

 only to Mexico and Central and Southern America, finding 

 their greatest development in Central America and Brazil. 

 The few Castniohles, or species of Mtyatlii/nius, known. 

 Inhabit the southern portion of North America, hailing 

 from the Southern States, from Florida, and from Arizona. 

 The genus Si/wmon appears to represent the Custniidee in 

 the vast continent of Australia. 



Of these aberrant forms Mi';/athi/mus t/iicca, the Yucca 

 Borer, is one of the most interesting. Although placed 

 with the Castniida., it has none the less given great trouble 

 to systematists, having been bandied from the butterflies to 

 the moths ; and, it must be owned, some still regard it as 

 a genuine butterfly. This species is common in the Gulf 

 States of America over extended regions, where its larva 

 commits serious depredations of the nature that its popular 

 name implies. 



It is a dull-coloured moth, and rests with wings 

 elevated —thus differing from the typical Castniidm — its 

 antenniB generally directed forwards ; also in smaller wings, 

 in smaller closer scales, in unarmed hind-wings, and in 

 stiffer, relatively shorter, antennae, it diverges in character 

 from the Castniidw. Its flight, which is diurnal, is an 

 extremely rapid darting motion as it passes from plant to 

 plant, principally in open spots. During April and May, 

 and earlier, it may often be seen in the morning 

 where the yuccas abound, darting hastily about after 

 its customary fashion, on laying thoughts intent ; and 

 as it pauses for a few seconds at one place, it fastens 

 an egg to some portion of a leaf. The eggs are laid 

 singly, though more than one may be put on the same leaf. 

 The larva, which is reddish brown, with a black head, 

 shelters itself in a web between some of the youug terminal 

 leaves. Usually it starts proceedings near the tip of a 

 leaf, working gradually downwards, eating the while, and 

 rolling and shrivelling the blade as it goes. It lives thus 

 among the leaves till about one-fourth grown, when it 

 enters the trunk, commencing the devastation for which it 

 is famed. Along the axis the trunk becomes bored and 

 tunnelled out into a cylindrical burrow, wherein the larva 

 makes its home, extending often to two or more feet below 

 the ground, and at its upper end lined with silk, generally 

 intermingled with a white, glistening, powdery material, 

 soapy to touch, and analogous with that of Hymenopterous 

 and many Homopterous larvae. At what stage of larval 

 development this powder is secreted is not known, but the 

 full-grown larva is always covered with it more or less 

 copiously, and doubtless it protects the invadrn- against 

 the mucilaginous liquor which the yucca freely exudes on 

 maceration. 



The funnel-like tube outside the burrow, made by the 

 twisting and webbing together of the tender leaves, when 

 partially devoured, is quite characteristic of the larva of 

 YiKcie. The tube is, indeed, built and extended often 

 several inches beyond the trunk or stem : from it the 

 builder, especially when young, emerges to feed, and the 

 small amount of matter besides silk used in its construc- 

 tion — the remnants of leaves and such-like substances — 

 have been obtained and worked into the exterior from the 

 outside. Pupation generally takes place at the top of the 

 burrow, just below the funnel-like projection, but without 

 the preparation of a well-formed cocoon. The pupa is 

 of a brown-black colour, and, like the mature larva, is 

 more or less densely covered with a white powdery bloom. 



Urania fulr/cm (Cectral America). Two-thirds natural size. 



It has long been a problem with systematic writers 

 what is the true situation in nature of the highly in- 

 teresting group of insects Uraniidc-. The day-flying 

 habits of the insects, together with their airy forms and 

 the extraordinary brilliancy of their colours, naturally led 

 to their being at first classed among the Rlioiialocem, but 

 later acquaintance with their transformations proves them 

 to belong to the Heterocerous division of the order. 



They are among the most richly ornamented [.<pidoptera 

 of that very brilliant order. It would be ditficult for art 

 to eft'ectually represent the changeable and resplendent 

 golden green of the numerous bars which contrasts with 

 the velvety black of the wings, and varies with every 

 change of light. The posterior wings are prolonged into a 

 single elegant pointed tail, closely resembling that appen- 

 dage in many swallow-tailed butterflies ; or there may be 

 present at tlie hinder extremity of the wings no fewer 

 than three distinct tails. The typical species of these 

 superb insects are natives of tropical America, where they 

 fly so high, and with such amazing rapidity, that it is 

 almost impossible to catch them, and the only way, there- 

 fore, to obtain good specimens is to rear the caterpillar. 



Urania boisdnialii, which inhabits Cuba, may be con- 

 sidered as one of the most beautiful l.t-pidni'tr'ia known. 

 It attains an expansion of wing of from four to four and a 

 half inches, with an undulated rim, the hollows of which 

 are more or less sparsely tipped with white ; otherwise its 

 colours arc velvety black and green. While the black of 

 the superior pair of wings is relieved with golden green 

 transverse lines, and their under side is nearly all black, 

 with transverse lines of a bluish green, on the black of the 

 inferior wings we nolo a longitudinal broad discal greea 



