530 



SCIENTIFIC NEWS. 



[Nov. 23, 1888. 



it merges, is at first erect (as in the Pea, figs. 8 and 9). 

 The leaflets are conduplicate, and all five are pressed 

 together laterally ; for at this stage the petiole has not 

 elongated sufficiently to allow of the pairs of leaflets 

 being separated. As the petiole grows the whole col- 

 lection of leaflets becomes more pendulous until they 

 expand, and the leaf ultimately assumes the horizontal 

 position . In the Garden Bean the leaves are conduplicate ; 

 but the margins are involute as well, so that the leaflets 

 resemble so many quills. 



(ii.) pendulous. Of the two types the following may be 

 selected : — The French Bean, Wood-sorrel (Oxalis), 

 Clover, and Laburnum as being ternate, and the Horse 

 Chestnut and Virginian Creeper as being digitate ; while 

 the Walnut will exemplify the pinnate type. 



The French Bean (Phaseolus vulgaris) bears at first a 

 pair of unifoliate leaves ; but those which succeed them 

 are ternate. While very minute in size (one half to 

 three quarters of an inch in length) the leaf is horizontal, 

 but the leaflets are conduplicate with their edges upper- 

 most. When a little larger (say, one and a quarter 

 inches) the petiole bends down angularly, and the 

 leaflets are in vertical planes, holding identically the 

 same positions as when adult and asleep. As they in- 

 crease in size, the leaflets rise up and take a horizontal 

 position. They now become subject to hypnotism, fall- 

 ing at night and rising again by day. 



The Wood-sorrel (fig. 12), Clover (fig. 11), and Labur- 

 num (fig. 10) all agree in having their three leaflets con- 

 duplicate, pressed close together laterally and suspended 

 vertically. The petiole is suberect in the Laburnum and 

 Clover, but strongly curved at the apex in the Wood-sorrel, 

 so that the minute leaf is under the concave end (fig. 12, 

 a and b). When the leaf of the Oxalis is asleep, the 

 leaflets fall vertically and bring their undersides in con- 

 tact (fig. 12, c), but never resume the conduplicate con- 

 dition again. The sleeping condition of Clover has 

 been described above ; but here, as in all other instances, 

 conduplication once lost is never resumed.* 



This seems to indicate that the danger from exposure 

 in the very young state being much greater than in the 

 adult, the protection is correspondingly more perfect. 



In the Horse Chestnut (fig. 13) the digitate leaf has at 

 first all the leaflets dependent and more or less covering 

 one another. This is exactly similar to the condition of 

 the leaflets of Lupinus pilosus when asleep, as described 

 by Mr. Darwinf (fig, 14). It may be added that the 

 leaflets of Lupin are at first clustered together and con- 

 duplicate. The Virginian Creeper has its five leaflets 

 at first conduplicate and suberect ; they gradually curve 

 over and spread themselves vertically like a star, not 

 unlike the method adopted by Lupinus pubescens, as 

 described by Mr. Darwin. 



The petiole of the Walnut-leaf (fig. 15), on emerging 

 from the bud (the scales of which, like those of the Ash, 

 are petiolar), curves strongly downwards, so that the 

 leaflets, which are conduplicate, stand in a vertical 

 plane. As the basal ones expand they still remain with 

 their surfaces vertical, and it is not until they are 

 approaching maturity that the petiole rises up and the 

 leaflets spread themselves out horizontally. 



Besides vernation, conduplication, and the subsequent 

 vertical position of leaves and leaflets, as calculated to 



* This is due to the fact, af least in Clover, that a thick layer of 

 chlorophyllaceous tissue is developed over the fibro-vascular bundle 

 of the midrib, thereby preventing the two halves closing again. 



t L. c. p. 341, fig. 137. 



protect them from the evil effects of radiation, hairs and 

 tomentum, etc., must not be forgotten as being bad con- 

 ductors of heat, and therefore very important aids to 

 protect the organs clothed with them. Foliar organs 

 and axes, when young, are often very hairy, silky, or 

 woolly, as the case may be, which in older states 

 become glabrous, either by the hairs becoming 

 more sparsely scattered by epidermal growth, or by 

 vanishing altogether. Similarly the stellate pubescence 

 or woolly clothing, which is not an unfrequent character 

 of the young condition, often disappears as soon as the 

 surfaces thus protected are sufficiently advanced to 

 require such additional aids no longer. As examples 

 may be mentioned the young shoots of Poplar, Apple, 

 Ivy, etc., while the leaves of Coltsfoot are at first densely 

 villous, but soon lose the cottony webs from the upper 

 surface as they become adult. 



Conclusion. — The examples given in this paper could, 

 of course, be multiplied indefinitely ; but enough seems 

 to have been stated to justify a belief in the general 

 accuracy of the deduction that vernation, conduplication, 

 the various positions taken up by developing leaves, etc., 

 all conspire to protect them from the evil effects of 

 radiation. 



THE URANIA RIPHCEUS. 



'"PHIS moth is interesting from two points of view. 

 Firstly, it would be at once pronounced a butterfly, 

 and a very brilliant one, by all persons who are not 

 specialists in insect-lore, and, secondly, because, whilst 

 the individual species in question is peculiar to Mada- 

 gascar, the other members of the genus Urania are 

 found only in the neotropical region. The Rev. Paul 

 Cambrone, S.J., who has already forwarded to our con- 

 temporary, Cosmos, an account of this insect in its matare 

 condition, is now enabled to give an account of its cater- 

 pillar and chrysalis. He writes: — "M. E. Perrot having 

 lately made a small journey of exploration to Alakaty 

 found some caterpillars of Urania riphoeus, which he 

 has forwarded to me. The caterpillar of Urania riphoeus 

 is long, and nearly uniformly cylindrical. It is five centi- 

 metres in length and about seven millimetres in mean 

 diameter. It is beset with isolated hairs or filaments 

 over its segments, characterised by their spatula-like 

 form, the narrower part protruding from the body of the 

 insect. The legs are sixteen in number, the three anterior 

 pairs being chitinous, and the five posterior membranous 

 pairs being yellow, speckled with black on the outer 

 side. The thick, broad head is also of a yellowish colour, 

 speckled with black. The scutellum is of the same colour 

 as the head. The stigmata are black. The underside 

 of the caterpillar is yellowish. The first segment of the 

 back is yellowish, speckled with black; the second is 

 black, and the nine others are of a yellowish white, also 

 dotted with black. The caterpillar feeds upon a plant 

 called by the natives hasomalay. 



" The caterpillar is transformed into a chrysalis in a 

 cocoon formed of a very transparent tissue of open 

 meshes, around which it collects the fibres of the 

 leaves. The pupa of the Urania riphoeus, as in most 

 moths, is rounded, cylindric-conical, and measures about 

 three centimetres in length by eight millimetres in its 

 maximum diameter. It is of a brown colour. 



" It remains in the pupa state for a fortnight, and the 

 mature insect issues from its cocoon at midnight. In its 

 perfect state it flies from January to May." 



