NATURE NOTES.

New Zealand Herald, Volume LVII, Issue 17483, 29 May 1920, Page 1 (Supplement)

NATURE NOTES.

. BY J. DRV/MMOXD, F.L.S,, F.Z.S. : A somewhat strange present has been sent by an anonymous corresponded who lives iii Gladstone Road, Gisborne. It came neatly wrapped in tissue paper, with a request that I should explain its function. It is part of the body of a- cicada, the part that contains the insect's music; box. Cicadas in New Zealand are better known to the public as locusts, but this is a name that should be discarded, as it is not correct, and leads to confusion. The only other name available, if the. Maori name, kihikihi, is not acceptable, is the Latin one, which at least is sanctioned by usage, as it has been in use for thousands of years. Almost everybody who has spent a summer. in New Zealand has heard the cicada. When thousands are together, the volume of sound is so great as to be disconcerting, but it never seems to me to become harsh and grating. It had, indeed, a soothing effect, which fits in with the spirit of a lazy summer day. The music is produced by a tynibal or drum, and membranes on the under-surface of the body. They I are- protected by a;' pair of . hard shields, and may be seen when these are raised. The tymbal is very delicate in structure. The cicada sets it vibrating. The vibrations are caught by the membranes,, which divide into chambers, the cavity in which the apparatus rests, and by this means the sound is intensified. The shields also, probably, have some intensifying effect:as well as acting as pro tectors. There is no record of anybody in New Zealand having seen a cicada at work producing the noise, bit the Rev. R, Wyillie was exceptionally fortunate in this respect in Guiana, and his account of the methods of a cicada there, no doubt, explains the methods of the New Zealand cicada. "One evening, when I was stand ing still, watching something else," he states, "my attention was arrested by the short, quick notes of a cicada within a few inches. of my eyes. To my delight, I saw the insect distending its abdomen with each short note. As it produced a long note I saw the abdomen gradually contract, as if the air that had been pumped in was being expelled with great muscular force. Just before the long note was finished, I Was fortunate enough to catch the little fellow in my hand, and then, to my delight and surprise, I found that by gently pressing the thorax, .1 could secure an encore at will. This lasted ' nearly all the time I was walking home.; and I was able to watch the, distention and contraction of the abdomen for nearly half an hour, long after the other cicadas had ceased their song for the evening. I concluded that the cicoda is able to fill the abdominal space with compressed air, and then force that air through the membranes." It is only the males that produce the noise. The females are silent throughout their lives. This was noted from. remote times, and led a Greek poet to make an ungallant couplet with regard to the happy : lives of the males, which need not be repeated here. Until recently, a theory that, the noise was a marital summons from the males to the females was generally accepted, but M. Henri Fabre, whose Observations of insects have attracted much attention, mainly on account of the style in which they are recorded, states that the theory hardly can be supported by the facts, as males and females often feed together on the same twigs, and that, there is no necessity for a male to. make a loud noise in order that the female- may know where he is: Fabre saya': "One does not spend months in calling a person who is 1 at one's elbow. Moreover, I have never [ seen, a female rush into even the most

deaiening orchestra, bight, is sufficient prelude.to marriage* for their sight is ex- ; cellent. There is no need for the lover ' to make an everlasting declaration; for his J mistress is his neit-door-heighbour. Is r the song a means, of charming, of touching J the hard-ofvheart? I doubt it. I observe ho signs of satisfaction in the females; I c have never seen them tremble or sway t upon their feet, though their lovers have i clashed their cymbals -with the most deaf- i ening vigour." New Zealand has no fewer than fourteen species of cicadas, but it .Hoes not possess , the most famous cicada in trit world, Tliis , is the seventeen-year locust of : the United , States, where the same wrong popular name is given to the insect. It appears in vast numbers in different parts of the ] States at different times, but it appears in each district only once in seventeen ' years. Last spring, the Government ! officers in the. Bureau of Entomology in Washington issued a warning that the cicada was due to appear in twenty states, -, which were named, and that as the insects are a pest, stops should be taken to deal. ; with them, Mr. R. L. Ditmars, curator of reptiles in the New York 'Zoological Society's Gardens, has informed me that , over the area described, the swarms appeared absolutely on. time. They were as mathematically correct - as an eclipse of the sun or of the moon. . Perhaps the strangest feature of this insect's life-history is that in its perfect stage, after seventeen years of toil underground and in total darkness, as an ugly grub, it lives for only a few weeks as a : perfect insect, flying in the air and.drinking in the glorious, sunshine, The. egg of a seventeen-year cicada is laid by the .perfect female in a hole she drills in a tender stem. She may lay two eggs there. They hatch in a few weeks, and the young cicadas crawl from the hole and launch themselves into space. They fall into a jungle of grass-Blades and.weeds. After scurry ing for places where their enlarged fore; . limbs: can -push''aside... particles of earth, they begin to. work their way into; the .ground They suck juices from thread-like roots; in the ground," and .■ their strength grows They..mine and toil'from root to root, until,' at "the. end of-seventeen years, ; they. : enter into/a higher stage of life. -In ■ emerging, from.„ the mines, nothing daunts them. 'overcome the obstacles presented by cinder roads and flooded ground. .Thousands of holes appear along the edges of -. cement - footpaths. . This has involved ■frenzied, tunnelling in a horizontal direction when it was found that the surface made. an,-.effectual-bar. In the case of flooded, ground, water-tight cylinders are -formed and are thrust up from the ground i itfi a'height above the surface of the water j ■From, the tops-of these cylinders the little- j builders; emerge at the same .time as the | emergence of other cicadas/ who have not met with the same difficulties:. ■: ..The male seventeen-year cicada is harmless,. All the mischief is" done by ,the female;- which, bores i holes in the stem of "trees for ■ the eggs I she will -lay in her short life as. a perfect I insect.. A part of an injured stem withers,;and dips, the woods; become spotted ' with sprays'.'of,..dead, \ brown, leaves,...and. ■ the 'forests' look -as if they had been scarred bv fire; . Fruit trees t are. attacked sometimes, but seldom, it is reported, to a serious extent if woodlands" are near and i available>V Mr. Ditmars has recommended j ' ■'residents'of the .'£' rated States to prepare I ■ i -for.;the"-'cicadas.' several " years . before, the j | emergence -is due He urges orchardisfs I \ •toV'ciilLivate.young and natural .trees where! the cicadas are-expected,,, in order to at- j .tract them away from the fruit- trees. , " ■}:/:'.■ Within:a."month after the ground has been riddled by the emerging myriads of insects; eggs.have been encased in. a twig. The- cicadas have completed their task and ended. their lives. One after another, they become less sure in flight and in foothold, and during the late afternoon : journeys they drop to the ground through the foliage. .Although stunned for a mo- • rnent, they crawl slowly over the, ground, i but are overtaken by the chilly dew, and i by morning they are dead. Some of the • impoverished bodies seem to be attacked i by a fungus, which grows rapidly and i completes the insects' destruction.;':■ The droning quickly becomes fainter day by , day and with the rapid disintegration,, all ; signs of the swarm, except the damaged: twigs, disappear.