February 1, 1894.] 



KNOWLEDGE. 



43 



when the insect is alarmed and tries to pull out its sting 

 suddenly, as is of course usually the case when, for example, 

 a hee stings a human being, it often happens that the 

 sting cannot be extricated quickly enough, but the bee in 

 its struggles tears itself away, leaving the sting and all its 

 appendages still sticking in the wound. According to Mr. 

 J. I). Hyatt, if a bee be allowed to sting a soft piece of 

 leather, it will be unable to withdraw the sting, and will 

 tear itself away, leaving the whole apparatus beautifully 

 dissected oiit, while the insect itself will fly away, appa- 

 rently not seriously incommoded by the loss. It is stated 

 that the queen bee is not very ready to use her sting 

 against human kind, reserving it for despatching her 

 rivals ; and that when she does sting a human being, she 

 is able to withdraw her sting more easily than a worker, 

 by turning round on it as an axis, and so giving the instru- 

 ment a corkscrew motion. Much of the muscular move- 

 ment connected with the act of stinging seems to be of a 

 reflex nature, so that it may take place some little time 

 after the death of the insect, and it is the painful experi- 

 ence of most persons who incautiously handle dead wasps 

 to find that death has not robbed them of the power of 

 stinging. 



With bees, whether solitary or social, the use of the 

 sting is evidently, since the insects are entirely vegetarian 

 in diet, merely a means of defence against enemies ; but 

 with the rest of the aculeate Hymenoptera the case is 

 somewhat difl'erent. Wasps are hunters, and expert ones 

 too ; their young are reared on animal food, and the 

 workers therefore hunt for prey to satisfy these claims. 

 The sting here comes in very usefully as giving them an 

 easier victory over the quarry, and as rendering it, when 

 caught, powerless to interfere with its transportation to 

 the nest. The same remark applies to ants. The fossorial 

 Hymenoptera are somewhat diflerently circumstanced. 

 Though a numerous group, they are not generally well 

 known, and therefore have no 

 popular names other than that of 

 sand -wasps, which they share 

 (wrongfully) with the solitary 

 wasps. As their technical name 

 implies, they are diggers, burrow- 

 ing into the earth, or into wood, 

 and they have a preference for 

 sandy places, where the soil is 

 easier to excavate. Each burrow 

 is formed by one insect, and 

 tenanted by one brood only, for 

 they are solitary in habits, i.e., the 

 species consist only of males and 

 females, and each female makes a 

 home for her own brood alone ; 

 the young, therefore, do not depend 

 upon the care of nurses, but are 

 left entirely to themselves, and 

 have to feed themselves from the 

 moment of their liberation from 

 the egg till they become pupa\ 

 Nevertheless, they do not collect 

 their own food, but a supply is pro- 

 ■S'ided by the mother before tliey 

 are hatched. Thus, as they never 

 need to leave their birth-cell, they 

 can afford to do without legs, which would, in fact, only 

 be in the way within the narrow confines of the cell ; 

 consequently, these larvje always take the form of foot- 

 less maggots. When the mother has made the cell, her 

 next business is to begin to provision it. The larvae are 

 carnivorous, feeding upon caterpillars, flies, gnats, spiders, 



Fig. .3.— Stiii|,'of Wasp : 

 a. dart ; h. lancot. cscapctl 

 fi'om grouve ; c, poison 

 bag ; d, feelers ; e, base of 

 ]]oisoii g'.and, the rest 

 liaTing been removed. 

 Magnified ten diameters. 



aphides, beetles, &c., the particular creature selected 

 depending upon the species of fossor. Each species 

 usually confines itself to one sort of prey ; the mothers 

 are, in fact, very good entomologists, able to distinguish 

 the right kind of creature amongst the multitude of species 

 of all kinds that they meet with in their explorations, and 

 often far more keen in knowing how and where to get hold 

 of a particular sort of insect than most human collectors. 

 In proceeding to provision the cell, then, the mother hunts 

 up a specimen of the proper sort of prey, deposits it in the 

 cell, and then lays an egg upon it. A store of provisions 

 of the same sort must now be got together in suthcient 

 quantity to last the larva its whole lifetime, and there is 

 also the further requirement that it must be in such a 

 condition as to remain fresh, and neither dry up nor 

 become putrid so long as the grub has any need of it. 

 The sting enables the mother to make the necessary 

 arrangements without difficulty. The prey, if thin- 

 skinned, such as caterpillars, is often strung slightly when 

 caught, enough to prevent it from struggling, but not so 

 much as to quite kill it. In this condition it is stored up, 

 too helpless to escape, but at the same time with as much 

 vitality left as will serve to keep it soft and fresh, and 

 prevent it from shrivelling up or becoming mouldy. Hard- 

 skinned insects, such as beetles, are stung to death before 

 being put beneath the ground ; then the dampness of the 

 soil softens their joints, so that by the time the grubs are 

 ready to proceed to the feast, the feast has been reduced 

 to a proper consistency for their jaws. The number of 

 corpses, or semi-animate bodies, with which the larder is 

 stocked of course depends upon the size of the insect to 

 be reared as well as upon that of the prey itself. For a 

 certain large species, which is shaped a good deal like an 

 ichneumon fly, a single large caterpillar suffices ; in other 

 cases, a dozen or so of small spiders, or some fifty or sixty 

 aphides, may be found piled up in a cell. Most of these 

 fossorial Hymenoptera are smaller than the generality of 

 bees and wasps, and hence their sting, though fatal to 

 their legitimate prey, has generally but a trifling effect 

 upon ourselves ; in fact, several species are extremely 

 reluctant to use their sting at all when handled. 



{To be continued.) 



FOSSIL WOOD. 



By the Eev. A. S. Wilson, M.A., B.Sc. 



A DELIGHTFUL experience awaits the botanist on 

 turning his attention to fossil plants. Entering 

 the realm to which pabeontology introduces us, 

 forms of singular elegance and beauty greet the 

 eye ; others are seen, strange and grotesque, which 

 bid defiance to all our previous conceptions. No one who 

 is not altogether destitute of imagination can contemplate 

 the exquisitely graceful outline of Sphenopteris, or the 

 ornately sculptured stem of Ulodendron, in fairly preserved 

 specimens, without catching a glimpse of this fairyland of 

 paleontology. 



We gain but an imperfect conception of any plant, how- 

 ever, from its external appearance alone ; for its proper 

 comprehension we must also know something of its life- 

 history and internal anatomy. This presents little diffi- 

 culty in the case of the leaves, buds and flowers enclosed 

 in the amber obtained from the Eocene strata of Germany. 

 Models of flowers belonging to the chocolate order, with all 

 their parts perfect, have been obtained by forcing melted 

 wax into certain cavities in the Tertiary tuffs near Sezanne, 

 in France. But without recourse to any expedient of this 

 kind Eenault procured from the Carboniferous strata of 



