Sept. 19, 1884.] 



KNOWLEDGE • 



2U 



larger than the former, the plant bigger, and the flowers 

 much fewer, and iit the top of the stems. Each flower, 

 instead i)f opening with wide clefts in the corolla, is a close, 

 egg-shaped Iwg, with a small round mouth and star-shaped 

 lips, through which the stigma slightly protrudes, and par- 

 tially closes the way. Of similar structure is the elegant pink 

 or cross-leafed heath, which has a tuft of nodding flowers at 

 the top of its i-lender stem. At first sight it does not 

 appear why botanists call it " cross-leafed " {Erica tetralix), 

 but if one of the whorls is snipped off with fine scissors aud 

 fixed upright in the wax, it will be seen that the four leaves 



Fig. 1 . — Erica vulgaris. 



Fig. 2. — Anther of Ling 

 (F, filament; f, tails). 



form a cross, and that at the base of each one is a scale 

 ■with a ruby glandular swelling at its base. The marginal 

 hairs on the leaves are also worth notice. An insect like a 

 bee could not thrust a tongue into these little bottles 

 without rubbing against the stigma, which is viscid 

 when the flower is ready for fertilisation, and as the 

 invading instrument goes further, it opens the ring of 



Fig. 3. — Cross-leaved heath. 



anthers and receives their pollen. To watch the process, a 

 bee should be caught in an inch-wide test-tube. This is 

 easily done by holding the tube close to the entrance of the 

 hive, and corking up the first bee that walks into it. A 

 sprig of the heath should then be inserted, and, after the 

 creature has exhausted its anger by rushing about, and 

 buzzing in the tube, it settles on the flower, and thrusts its 

 tongue down among the anthers. The one before me, as I 

 write, cannot reach the bottom of the flower cup. Re- 

 moving the pink heath, I replace it with a sprig of ling, 

 which seems to please the insect, and it forages diligeutly 

 from flower to flower, easily reaching the bottom. This 



process is ■watched ■with a H-in. lens, the lowest of a set 



of three, as the opticians sell them in tortoiseshell mounts. 



The bell of the cross-leaved henth shnuld be 0|.ened by 

 reuioving one side or the upper half, which can be done 

 with needles. This discloses the round, green, ribbed ovary 

 the pinkish style, and green stigma, with the group of 

 tailed anthers below it. Fig 1 shows the form of the ling 

 flower with its open corolla ; Fig. 2, one of its tailed 

 anthers ; Fig. 3 represents the elegant bell of the cross- 

 leaved heath ; and Fig. 4, the same, more magnified acd 

 with the upper part torn away to show the pistil, sur- 

 rounded with the group of tailed stamens. 



I frequently find a species of thrip in the flowers of the 

 ling, in its larval and mature states, and I cannot discover 





that it does the Hower any harm. It can suck the nectar 

 without piercing the corolla, and that food does not appear 

 to yield the material that forms the pitchy excrement of the 

 greenhouse plague, which does as much harm by depositing 

 this stuff as by its feeding upon the chlorophyll. 



STATISTICS OF BARATARIA. 



By Grant Allen. 

 I. 



BARATARIA is an island in the Utopian Ocean, 

 containing a population of one thousand adult per- 

 sons, of whom five hundred are males and five hundred 

 females. All these five hundred couples are newly mar- 

 ried ; they have just been planted as a colony on the 

 island ; and the Director-General of Statistics is now en- 

 gaged in drawing up some interesting calculations as to 

 their probable natural increase during the next five or ten 

 generations. 



I must apologise at the outset for this very abrupt method 

 of plunging in medias res ; but if one wishes to expose a 

 fallacy, there is no better way of going to work than by 

 reducing it at once to its simplest elements. Now, there 

 are a great many rampant fallacies about races and popula- 

 tions at present implicitly current in the world at large, 

 which, perhaps, may best be met by positing the simple 

 and easily comprehended case of the island of Barataria. 



