HARDWICKE'S SCIENCE-GOSSIP. 



107 



not that of secreting the pellucid liquor which the 

 ants so covet, and which in the aphis of the sycamore 

 falls upon the upper surface of the leaves beneath 

 those under which the insects lurk ; this is anal. Can 

 they be the extension and termination of the respi- 

 ratory system ? In all the species that I have observed 

 in which the cornua were developed less or more, I 

 never yet saw moisture exude from or stand on the 

 summit of these organs ; and for days together I have 

 had the ivy aphides under observation when they were 

 being numerously attended on, caressed, and freely 

 milked by both a red and black species of ant, this 

 being, I imagine, a crucial period. 



Charles Robson. 

 Elswick, Newcastk-upon- Tyne. 



A STUDY OF THE VARIATION OF 

 VANESSA URTIC^E AND OF SOME 

 OTHER BUTTERFLIES. 



By A. H. Swinton. 



TO the evolutionist, thinks Mr. Mosley, varieties 

 may prove of the utmost interest as pointing to 

 races gone before, or as offering indications of the 

 approach of a new species. "Are there not," he 

 says, "some occasions when we can call to our 

 memory instances where the type has given place 

 to the variety, and the variety in turn has become the 

 type ?" Who knows not, for instance, the little brown 

 Argus agrestis, that out over the pasture-lands 

 mingles its warm nutty-brown, dashed with orange 

 spots, among the clear sapphire sparkle of the droves 

 of blue butterflies that start up before the footsteps ? 

 Twice in the year it greets us : once when the spring 

 rains are heavy, and the thick boughs resound to the 

 song of the robin ; and again at autumn, when the 

 grass is scorched and dry, and the clearer sky is 

 tracked by floating thistle-down. Go north to 

 Edinburgh and traverse the Saxon-speaking lowland 

 as far as Aberdeen, and you [will there see appear 

 once a year another blacker butterfly with a clear 

 white fleck, like a piece o' the gowan, on its wing, 

 and no more of those bright orange cairngorms than 

 you may see displayed on the hinder wing of the 

 female of the commonest blue : and yet this less 

 canny thing is nothing more than a local alpine 

 variety of the same rural butterfly, whose name has 

 the advantage of being a celebrated typographical 

 error. In my school-days wiseacres had it a species ; 

 and well I remember an excursion to Arthur's Seat, 

 and mad-cap hunt all over the Queen's Drive, and 

 down among the moist meadows gleaming with 

 dragon-flies, in search of the then far-famed Arta- 

 xerxes, which of course never turned up ; no, not 

 when I had dared the last " no trespass " board, and 

 found myself arrived opposite a garden gate, where, 

 horror of horrors, a lassie was taking the evening air. 



But insects not alone do and have varied on cer- 

 tain spots recluse, they change likewise in time, and 

 either circumstance is greatly dependent on the exis- 

 ting climate. Many whites, blues and Vanessae, 

 array themselves at periods of the year in alternate 

 spring and summer dress, the most noteworthy of 

 these being the butterfly denominated by the French 

 La carte geographiqitc, which, as Boisduval first re- 

 marked in the year 1828, flaunts at spring in the 

 most vivid of fawn colours, and then for the rest of 

 the summer appears draped in black, branded on the 

 wing with a different check ; becoming thereby as 

 changed in aspect, as though the fritillary in the 

 woods had produced a White Admiral butterfly as its 

 progeny. Should, however, a drier or a more humid 

 season arrive, then another pattern-variety may be 

 looked for, intermediate in character : such a season 

 was 1865, unusually open and dry on the Continent, 

 when many butterflies and moths produced an extra 

 brood. That the epithet geographiqitc has in more 

 ways than one been happily conferred on Vanessa 

 kvana, and that such changes of costume may be 

 often geographical quite as much as tweeds, mantles, 

 cinctures, hats or turbans are, may be gathered 

 from the fact, that white-bordered Camberwell 

 beauties, which have become a race in Sweden, 

 farther south appear similarly, but as a passing spring 

 variety of the buffones ; and even the redoubted 

 Artaxerxes afore mentioned, or at least an intermediate 

 form, has been produced abnormally at Brighton 

 during July 1856. Other instances of seasonal 

 varieties appearing from time to time in Central 

 Europe, and establishing themselves as local races on 

 its northern and southern confines, might be noticed ; 

 but there still remains a most interesting field of 

 labour in this direction, that cannot but recommend 

 itself to the attention of the entomological tourist, 

 resident abroad, and the biological worker. 



And if time and place mean change, and insects are 

 thus disseminating themselves in new races, who 

 would not desire to investigate farther the harmonies 

 that loom on the gloom ; and in the vacillating play 

 of colour and pattern to cast each horoscope, and so 

 trace the long butterfly pedigree coming down to us 

 from that remote period, when the savage forest 

 stretch of India and America had not receded from 

 European acres where they lay blended ; or the flora 

 and fauna, so to speak, undergone their last selection 

 and become as we now see them ; rural with heather 

 and dog-roses, oak woods, corn-fields and willowed 

 brooks ? As the mathematician, then, draws his base 

 line, and measures the angles it makes with those 

 remote periods whose position and relations he is 

 desirous to ascertain, so let us employ the recognised 

 systematic and geographical arrangements of butter- 

 flies, and by their means co-ordinate some of those 

 ancestral features that greet us, as we turn backwards 

 on the Lethean stream of time towards this ancient 

 luxuriousness of wildered nature wantoning in its prime. 



