244 



KNOWLEDGE. 



[NOVKMBEH 2, 1896. 



uredospores continue to propagate the uredo form of the 

 fungus indefinitely upon the wheat, but the telutosporos or 

 sporidia arising from them will only grow mycelia if sown 

 on the leaves of the berberry. 



In not a few instances these relationships have been 

 established by direct experiment. Dr. C. B. riowrlght 

 succeeded in producing jrcidia on the hawthorn and 

 mountain ash by infecting their leaves with telutospores 

 taken from the juniper, and on the nettle with telutosporeg 

 from a species of Carox. Conversely, with ajcidiospores 

 from the nettle he obtained the uredospores of riiccinin 

 can'cis on Carex, and spores from the colt'sfoot cluster-cup 

 placed on the meadow grass developed the uredo form of 

 P. jiotiniiii. The u'cidiuin of the berberry gave rise to 

 P. (irniiiiiiis on grass, and berberry leaves infected with 

 telutospores from the latter developed ivcidia of the usual 

 form. Check plants which in these experiments were not 

 inoculated yielded negative results ; the possibility of 



■,.sj»r 



error was thus eliminated. It may therefore be taken as 

 conclusively proved that many of these leaf fungi exist in 

 alternate generations as parasites on distinct plants, with 

 forms so unlike that the successive phases in the life cycle 

 of one and the same fungus were for long regarded as 

 different species and classified in separate families. The 

 brilliant orange and scarlet tints exhibited bv so many 

 Uredines are due to the presence in their cells of drops of 

 highly-coloured oil. They differ from the PeronosporeiP in 

 their septate mycelium, and are less destructive, as the 

 mycelium does not extend through the entire body of the 

 host, but the damage is usually restricted to the small 

 affected areas of the leaf. Sexual reproduction has not 

 been observed in the Uredines ; there are, however, grounds 

 for the belief that a process of fertilization really takes 

 place, but the consideration of this question must be 

 reserved for another occasion. 



DAY-FLYING MOTHS. 



By L. N. Badenoch. 



A POPULAR division of the r^pidoptem, or scale- 

 wings, in England, is into butterflies and moths ; 

 the former being termed liiunii, the latter 

 Xocturni. In most Continental languages one 

 principal word serves for the two great Lepidop- 

 terous groups. Thus, papillon, in French, may stand for 

 either a butterfly or a moth, and they are distinguished 

 respectively as papillon tie jour and pnpillon de nuit. 



But since, in fact, many of the species of the nocturnal 

 Lepidoptera are day-iiiers, and, vice vers't, not all the diurnal 

 Lepidoptern fly by day, the habits of these insects do not 

 seem to prove a good basis for separation. In order to 

 avoid the misconceptions producf d by the terms "diurna " 

 and "nocturna," Boisduval, a French entomologist, pro- 

 posed to substitute Hhopnlocera (club horns) for the 

 butterflies, and Heterucera (different horns) for the moths. 

 At first glance few distinctions appear more happy than 



this — few classifications more natural. It was no sooner 

 announced than it was recognized as a most convenient 

 arrangement, and it <|uickly came into general use. It is 

 founded on the structure of the antennii'. A marked 

 thickening towards the end almost universally characterises 

 the antennii' of the HlKiiuilorera. Such being the case, it 

 is undoubtedly a character of primary importance. But a 

 certain family of moths (Spliiiu/ida-), by their antenme 

 thickening towards the end, though terminating suddenly 

 in a point, bring the two groups into near relationship, and 

 lessen their value, while the most interesting Castniiilm 

 and Vnmiiila (of which more anon) so intimately connect 

 them that these families have sorely perplexed systematists 

 as to whether their rightful position was with the one 

 group or with the other. 



In a word, though we may speak of Hhopalocerous and 

 of Ileterocerous characters, there is no one character 

 which infallibly severs the two divisions. The more 

 intimate our knowledge of animal forms, past and present, 

 becomes, the more our demarcations give way. As we 

 arrive at a true conception of the relations of animals we 

 realize the closer approach of the different groups, until 

 we perceive an almost continuous chain. 



Let us glance at the curious and abnormal collection of 

 pretty insects, Castniida, which, in some respects, combines 

 the characters of both Lepidopterous divisions, but in 

 modern opinion has most attinities with the moths. LinuiiBus 

 and all the writers of the last century regardi^d the 

 species of the genus with which they were acquainted aa 

 butterflies, including them in the great group PapHia, on 

 account of the clubbed structure of their autenniB. At 

 the beginning of the present century, when this group was 

 broken up, the genus Caatnia was established, though 

 Fabricius still retained it among the butterflies. But when 

 the antennsB are carefully examined, they do not exhibit 

 the real Ehopalocerous structure. In like manner, tiie 



Thaliura Phipheus (Madagascar). Two-tliirds natural size. 



Castnians differ from other groups of Heterocerous 

 Lepidoptera in the complicated arrangement of the veins 

 of the wings, and in various ways. 



In general appearance they vary much, but, typically, 

 they have large wings, with loose and remarkably large 

 scales, and a position in repose deflexed or incumbent, 

 being furnished with a wing-guide or guides ; and the 

 antennie, though club-like at the tip, are generally long 

 and more or less supple. All these characters are constant, 

 and are Ileterocerous characters. As a rule the head 

 is broad, and the body large and somewhat pointed. 

 The Castnians resemble butterflies in this particular, in 

 their evidently diurnal habits, as evinced by the brilliancy 



