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Show 428 HABITS OF INSECTS. CnAP. XI. He gathered in Switzerland 100 flower-ste1ns of. the common blue variety of the monkshood (Acon~tum napellus ), and not a single flower .was p~rforated;. he then gathered 100 stems of a white vanety grmving close by, and every on~ .of th: open fl~wers had been perforated. This surpns1ng chffe~ence In tho stat~. of the flowers may be attributed with .much probability to the blue variety being distasteful to bees, from the presence of the acrid matter which. is so gen~ral in .the Ranunculacere, and to its absence In the wh1te variety in correlation with the loss of the blue tint. According to Sprengel,* this plant is strongly ~roterandrous; it would therefore be more or less stenle unless bees carried pollen from the younger to the older ~ow~rs. Consequently the white variety, the flowers of whiCh were always bitten instead of being properly entered by the bees, would fail to yield ~he full number of seeds and would be a comparatively rare plant, as Dr. Ogle informs me was the case. . Bees show much skill in their manner of worlnng, for they always make their holes from the ou~si~e close to the spot where the nectar lies hidden withm the corolla. All the flowers in a large bed of Stachys coccinea had either one or two slits made on the upper side of the corolla near the base. rrhe flowers of a Mirabilis and of Salvia coccinea were perforated in the s:1me manner ; whilst those of Salvia grahami, in which the calyx is much elongated, had both the calyx and the corolla invariably perforated. ~rhe flowers of Pentstemon arqutus are broader than those of the p l ants J·U S t naro ed ' an·d two holes alongside each other had here always been made just above the calyx. In these several cas~s the perforations were on the upper si· d e, b u t · 1 Ant~rII * • Das Entdeckt~,' &c. p. 278. CHAP. XI. PERFORATION OF THE COROLLA. 429 rhinum ma.fus one or two hole~ h d b lower side, close to the little pl~ t bee,n made ?n th o u erance which r presents the nectary, and therefore direct! · f e-and close to the spot where the nect , . y ln ront of B · ar 1s secreted. ut the lnost remarkable case of skill d . d known to me, is that of the perforation ofatnh JflU gment L a z · e owers of a ~yrus sy ~eslrtts,. as described by my son Francis *· The nectar In this plant is enclosed within a tub~ f~rn:ed by the united stamens, which surround th~ pistil so closely that a bee is forced t . t . b . . o 1nser Its pro oscis outs.i de the tube '. but two nat ura 1 roun de d p. assages or onfices are left i:ri the tube n ear. th e b ase In order that the nectar may be reached b th b ' N f d · . Y e ees. owh ~y son oun . In sixteen out of twenty-four flowers on t IS ?lant, and In e.leven out of sixteen of those on the cultivated eve.r lasting pea' whi'ch I·s ei'th er a van·e ty . of the same species or a closely allied one, that the left passage was larger ~han the right one. And here comes theremarkablepoint,-the humble-bees bite holes through the ~tandard-petal, and they always operated on the left side over the passage, which is generally the larger of the two. My son remarks : "It is difficult to say how the .bees could have acquired this habit. Whether they di~covered the inequality in the size of the nectar-holes In sucking the flowers in the pro , d th . 1 . d . pei way, an en utlise this knowledge in determining where to .gnaw the hole; or whether they found out the. best s~tuation by biting through the standard at ~an~~s. points, and afterwards remembered its situation In VISiting other flowers. But in either case they show a remarkable power of making use of what they have learnt ~y experience." It seems probable that bees owe theu skill in biting holes through flowers of all * 'Nuture,' Jan. 8, 1874, p. h9. |