88 



HARDWICKE'S SCIENCE-GOSSIP. 



[Afkil 1, 1870. 



head bears no small resemblance to that of a fat- 

 bodied garden spider. So feeble are its limbs, that 

 they are practically of very little use in locomotion, 

 and even when they are cut off, the creature cau 

 move nearly as well as when they were in their 

 places. From the front of the head project a pair 

 of long, slender, curved mandibles, which give the 

 first intimation that the grub has anything formidable 

 in its nature. These mandibles are curiously made, 

 being deeply grooved throughout their length, and 

 permitting the maxilla 1 , or inner pair of jaws, to play 

 up and down them. 



"Inert and helpless as it may seem, this grub is a 

 ruthless destroyer of the more active insects, and, 

 moreover, seldom catches any but the most active. 

 Choosing some sandy spot, where the soil is as far 

 as possible free from stones, it begins to form the 

 celebrated pitfalls by which it is enabled to entrap 

 ants and other insects. Depressing the end of its 

 abdomen, and crawling backwards in a circular 

 direction, it traces a shallow trench, the circle vary- 

 ing from one to three inches in diameter. It then 

 makes another round, starting just within the first 

 circle, and so it proceeds, continually scooping up 

 the sand with its head, and jerking it outside the 

 limits of its trench. By continuing this process, 

 and always tracing smaller and smaller circles, the 

 grub at last completes a conical pit, and then buries 

 itself in the sand, holding the mandibles widely ex- 

 tended. 



"Should an insect— an ant, for example — happen 

 to pass near the pitfall, it will be sure to go and look 

 into the cavity, partly out of the insatiable curiosity 

 which distinguishes ants, cats, monkeys, and chil- 

 dren, aud partly out of a desire to obtain food. No 

 sooner has the ant approached the margin of the 

 pitfall, than the treacherous soil gives way, the poor 

 insect goes tumbling and rolling down the yielding 

 sides of the pit, and falls into the extended jaws 

 that are waiting for it at the bottom. A smart bite 

 kills the ant, the juices are extracted, and the empty 

 carcase is jerked out of the pit, and the Ant-lion 

 settles itself in readiness for another victim. 



" Sometimes, when a more powerful insect, such'as 

 a large wood-ant or beetle, or perhaps a hunting 

 spider, happens to fall into the pit, the Ant-lion does 

 not obtain a meal on such easy terms. The victim 

 has no idea of surrendering at discretion, but tries 

 to scramble up the sides of the pit, aud in its furious 

 exertions it brings down the sand in torrents, filling 

 up the pit, making the slope of the sides shallower, 

 and so rendering its escape easy. Then there is a 

 battle between the Ant-lion and its intended prey, 

 the one bringing the sand into the pit and the other 

 flinging it out again so as to restore the steepness 

 of the sides, and to deepen the pit. 



" Sometimes a quantity of the sand flung by the 

 Ant-lion happens to fall on the escaping victim, 

 knocks it over, and enables the devourer to grasp it 



in the terrible jaws, which never open but to reject 

 the dead and withered carcases; sometimes the 

 insect is tired before the Ant-lion, and suffers itself 

 to be captured ; and sometimes, though very rarely, 

 it succeeds in making its escape. In either case 

 the pitfall is quite out of shape, and instead of re- 

 arranging it, the Ant-lion deserts it and makes 

 another. Some writers have said that the Ant-lion 

 flings the sand at its escaping prey with deliberate 

 aim aud intention. It does nothing of the kind, but 

 only tosses the sand out as fast as its head can work, 

 without aiming in any direction, or having any idea 

 except to prevent the pit from being filled up. 



" Its earth-burrowing life does not cease until it 

 assumes the perfect state. When it has passed its 

 full time in the larval condition, and is about to 

 change into a pupa, it spins a silken cocoon of a 

 globular form, and therein remains until it is about 

 to assume its perfect condition. The pupa then 

 bites a hole through the side of the cocoon, and 

 projects its body half out of the aperture. The 

 pupal skin then withers, bursts, and the perfect in- 

 sect emerges. Scarcely has it taken the first few 

 breaths of air, than its abdomen, which before was 

 short, so as to be iucluded within the cocoon, ex- 

 tends to nearly three times its original length, so as 

 to resemble that of the Dragon-fly ; the curious 

 antenna; unrol themselves, the wings shake out by 

 degrees their beautiful folds, and in a short time the 

 lovely insect is ready for flight. It is scarcely pos- 

 sible to imagine a more complete contrast than that 

 which is exhibited by the larva and the perfect in- 

 sect, and if the two were placed side by side, no one 

 who was not aware of the circumstances would 

 think that they are but two stages of the same 

 insect." 



ELD-HAL FINDINGS. 



~A /TY remarks will scarcely bear the construction 

 -k*-L that Mrs. Watney seems to put on them. I 

 did not say that Elm timber was without utility, 

 but that it had no special excellence over other 

 woods, unless in withstanding the action of water. 

 I shall not dispute that it may be made to assume 

 a mahogany colour by treatment with "some par- 

 ticular acid " — many other woods can be made to 

 do the same. 



I have no doubt brown paper may be made from 

 its bark ; as 1 know it may be from a great variety 

 of substances— wood for instance. 



Before Mrs. Watney mentioned it, I had not 

 heard of elm-bark being a dye-stuff; aud, having 

 no special knowledge of this branch of the arts, I 

 have inquired about it from a friend, who is engaged 

 in the preparation of dyes, and is well informed 

 on the subject. He tells me : — " The bark has, I 

 believe, been tried to dye a kind of brownish colour ; 

 but it is not used at all now." For information on 



