Aug. 3, 1883.] 



♦ KNOWLEDGE ♦ 



05 



^^^f^^^^?*^ 



AN li^miRATED 



MAGAZINE ofB^ENCB 



LONDON : FRIDAY, AUG. 3, 1883. 



Contents of No. 92. 



P\GE 

 A Naturalist 's Year. Wasps and 



Flowers. By Grant Allen 63 



The Moralit)- of Happiness : Con- 

 duct and Duty. By Thos. Foster 66 

 The Chemistry of Cookery. XIV. 



BvW. Mattieu "WiUiams 67 



Pretty Proof of the Earth's Botun- 

 dity. (///««). By E. A. Proctor . 68 



How to Get Strong 70 



Pleasant Hours with the Microscope. 

 (/Has.) ByH. J. Slack 71 



Niagara. Illlns.) By E. A. Proctor. 72 



Laws of Brirhtness. VII 71 



Discovery of the Chief Division in 



Saturn's King. Bv Capt. Noble ... 75 

 The Face of the Sky. By F.E.A.S. 77 

 Paradox Column : A New Theory of 



Copernicus 77 



Correspondence 77 



Our Mathematical Column : Geome- 

 trical Problems. X 78 



Our Cheas Column 79 



A NATURALIST'S YEAR. 



By Grant Allen. 

 XVIII.— WASPS AND FLOWERS. 



ON the very summit of the wind-swept heath, scarcely 

 sheltered from the north by a ragged row of 

 straggling Scotch tirs, a colony of broom manages somehow 

 to battle hard for life against wind and weather, while on 

 its roots the fat tuberous stems of the greater broomrape 

 have fastened themselves vigorously to suck out whatever 

 little sap the poor drained plants can spare, with all the 

 ruthless, leech-like greediness of born parasites. Broom- 

 rape, we call the withered brown weed, in fact, in good old 

 English, for this very reason, because it roots itself firmly 

 on the underground stem of the broom, and violates or 

 plunders it till almost nothing is left of it but bark and 

 wood. It is a tall, wilted-looking thing, this broomrape, 

 so dry, and grey, and faded, that you would hardly take 

 it at lirst sight for a living flower at all ; you would be 

 much more likely to pass it by unnoticed as a sere and 

 withered stalk covered with last year's empty seed- 

 vessels. If you look at it closely, however, you 

 will see that, though it is almost leafless, like 

 most other thoroughgoing plant-parasites (having only 

 thin stem-scales instead of green foliage) it is, 

 nevertheless, a fresh, vigorous, and succulent living 

 spike of dingy blossoms. At this moment, the spikes are 

 all surroundeti by belted black and yellow wasps, whom I 

 have often seen hovering before around the dull flowers ; 

 for greater broomrape is a wasp-fertilised plant, though the 

 fact seems to have escaped the observant eye even of that 

 most patient and careful of German naturalists, Hermann 

 Midler. Everybody knows, of course, the close connection 

 that exists between bees and flowers ; but I don't think 

 most jicople are aware that there are a few exceptional 

 plants which depend almost entirely upon wasps for the 

 due conveyance of their pollen from head to liead ; so 

 perhaps 1 can't do better than take this ding)' brown 

 broomrape for the text of a short discourse on this very 

 subject, and point out how far tlu! peculiar a-sthetic tastes 

 of the omnivorous wasps have reacted upon the special 

 ilowors on which they have concentrated their unconscious 

 botanical efl'orta. 



Wasps, as we have all observed, are very promiscuous 

 feeders. They will eat almost anything they can get, from 

 a good piece of raw beef to a plum or a potato. Hence, 

 like most other promiscuous feeders, they have not acquired 

 any marked taste for beauty of form or colour. As a rule, 

 in the animal world, love of colour is found only among 

 those l)irds cir insects which restrict themselves entirely to 

 honey-sucking in brilliant blossoms or to eating equally 

 brilliant fruits. On the other hand, wasps are not wholly 

 devoid of the flower-haunting habit ; for they are very fond 

 of sugar and all other sweets, as we have often noted both 

 in grocers' shops and at our own dessert. So they seek for 

 honey in a few special and peculiar blossoms, which have 

 thus been compelled to adapt themselves to the very low 

 tastes of the.se uncanny insect allies. Bees are fond of 

 flowers with long tubes, which preser\e the nectar from 

 other thieving species; and in order to allure their fastidious 

 eyes, such blossoms have acquired brilliant tints of purple, 

 blue, or crimson, which are very attractive to the honey- 

 loving aristocrats of the insect world. But the wasps care 

 nothing for such beautiful a>sthetio displays ; they are 

 strictly practical insects, with a decided eye to material 

 advantages, and all they ask is that the flowers they 

 patronise should not play at fox and stork with them, by 

 concealing their nectar at the bottom of a long and narrow 

 tube. Wasp blossoms, in short, must have shallow, open, 

 cup-shaped corollas, just liig enough to lit the insect's 

 head, and with abundant honey so disposed that it can 

 be readily abstracted without much trouble by the vespine 

 mouth. They need not be liright^coloured ; indeed, brightness 

 of colour, by attracting other insects which are less adapted 

 for fertilising them, would prove actually disadvantageous 

 to the species ; so as a class they are the very dingiest and 

 dullest of known flowers, being specially modified, as has 

 been quaintly said, " to suit the wants of an insect circle 

 possessing very uncultivated ,i>sthetic tastes." You could 

 not have a better example of the group than that afforded 

 us by this brown and dry-looking greater broomrape. It is 

 inconspicuous enough to keep away all other insects ; and 

 those few venturesome flies that do venture near it, allured 

 by the smell of honey, are sure to be quickly driven off by 

 the sharp jaws and deadly stings of its natural possessors, 

 the wasps. 



We have not very many native wasp-flowers in England, 

 but what few we have are quite sufficient to give us a very 

 good general idea of the eti'ects produced by such very 

 special and exceptional selection. The commonest among 

 them are the two fig-worts or scrophularias, which grow 

 abundantly by the water's side. These very odd and un 

 canny blossoms are shaped so as just to form a hood or 

 helmet for the wasp's head ; and when he inserts his mouth 

 into the flower, he rubs the pollen from the stamens 

 last visited on to the forked and bent stigma with un- 

 erring certainty. In colour, the corolla of the fig-worts is 

 an indescribable dirty olive brown, with a toucli of chocolate 

 red and green in it, not at all pretty, but extremely queer 

 and noticeable. You can't stand by the side of one for 

 five minutes without seeing it visited by at least one wasp, 

 and on bright, sunny mornings you are pretty sure to see 

 half-a-dozen. Another somewhat rarer English wasp- 

 flower is the broad-leaved epipactis, an orchid growing in 

 shady places, and not infrequent on the outskirts of moor- 

 land farms. In colour, it is almost the same dingy purplish- 

 green as the fig-worts, and it is arranged so as to form a 

 very similar hond-shaped cap, just fitting the wasp's head. 

 So far as family goes, these two weeds are as wide apart 

 as any two flowering plants can possibly be, for the one is a 

 very advanced monocotyledon, while the other is a highly- 

 moditied type of dicotyledon ; but their adaptive peculiari- 



