For September, 1921 



703 



flowers, are similar. Their color which is green makes 

 them practically invihible and indistinguishable. The an- 

 imal knows the value of its protective resemblance and 

 coloring and remains on one and the same place even 

 when disturbed. 



Over there by the hazlenut bushes a peculiar, tiny beetle 

 runs about, the hazelnut borer. In its work this insect 

 is best observed when the hazlenut flowers have fallen 

 and the young nut begins to develop. Then the female 

 bores a tiny hole into the nut and places in it a single egg. 

 In this way one nut after another is bored and becomes 

 the repository of the eggs. When the female has laid all 

 of its eggs it has accomplished its purpose in life and it 

 dies. In the meantime the larvae have hatched from the 

 eggs. These then eat the kernel but leave all those parts 

 which are necessary for the full development of the nut. 

 Although about three-quarters of the kernel is eaten by 

 this white larvae, externally the nut appears perfectly 

 sound. When the larvre is fully developed it gnaws a 

 round hole through the shell of the nut, crawls through it, 

 falls on the ground, penetrates a short distance into it, 

 and here it makes its metamorphosis into a beetle. 



A parasitic life is led by the Ichneumon flies. The 

 greater part of the life of the larvae is passed in the bodv 

 of other insects, where they live upon those tissues which 

 are not essential for the life of their involuntarv host. 

 Just before the larvre stage is ended and the pupa stage 

 begins, do these insects bore their way through the skin 

 of the host. A few remain in their host until the pupa 

 stage is completed, under these conditions the host 

 pupates also but the Ichneumon fly leaves the pupa of the 

 host before it dies. The females of these insects prefer 

 caterpillars in which to lay their eggs, but these useful 

 parasites also deposit their eggs in other larvae. The fe- 

 males fly around their intended victim and then calmly 

 settle upon it. Instinctively the larvae knows its enemies, 

 it turns and twines convulsively, but all in vain, the fly 

 does not even seem to notice its convulsions. The Ichneu- 

 mon fly remains quietly upon the caterpillar and enters its 

 egg tube the whole length of the body. In this position 

 the fly remains motionless for a few minutes, the abdomen 

 moving slightly when the egg passes through the egg- 

 tube and is pressed into the body of the caterpillar. 



In those protected places of the garden where the wind 

 does not ripple the leaves, the home of the leaf lice are 

 found. Here they sit on the young shoots and have 

 bored their sharp proboscis into the tlelicate plant tissues 

 from which they drink the sap. The sucking tube pene- 

 trates deep into the tissues and the contents of one cell 

 after another is sucked dry, but the main conducting 

 bundles remain untouched. The.se animals take large 

 quantities of carbohydrates and proteids from the plants. 



Leaf lice multiply very rapidly in dry, hot weather and 

 when the plants grow luxuriantly by the addition of ma- 

 nure. Many species of leaf lice have, on the third ab- 

 dominal segment, two .short tubes, the honey tubes, and 

 nearly all species exude from their abdomen a gelatinous, 

 sugary fluid, the so-called honey dew, with which thev 

 cover the leaves. This is eaten by many insects, especially 

 by ants. 



The many [)€culiar conditions in the reproduction of 

 leaf lice lacks, in a few instances, a complete explanation. 

 The Winter eggs which hatch in Spring are only capable 

 of developing "females which are able to bring young 

 into the world without fertilization. The latter, 

 after a few molts, also give birth to living young without 

 being fertilized. In this manner about nine .generations 

 can follow each other during the warm season. Only the 

 last generation is capable of developing males and fe- 

 males. These, after fertilization has taken place, lay the 

 Winter eggs. The males are nearly all winged, the fe- 



males but seldom. The development of the sexes de- 

 pends upon the lowering of the temperature in the Fall, 

 during the warmer season only parthenogenetic reproduc- 

 tion takes place. 



Other sap sucking insects are the numerous species of 

 cicada which, especially in the warmer countries, develop 

 into countless numbers. The tiny forms — which as a 

 rule are too small for the unaided eye to appreciate their 

 form — belong to the most peculiar living things which Na- 

 ture has developed in the insect world. When ma.gnified 

 many of these appear like the monsters of former geo- 

 logical epochs, protected with armor, and armed with 

 horns and other protuberances. The playground of these 

 tiny insects are the meadows and the foliage of trees and 

 shrubs. Upon walking through these places one scares 

 many of them and these then let themselves down upon 

 the clothes, where they resemble little bars. Sometimes 

 the}' will run rapidly for a short distance, but often they 

 are only seen for a moment. Then they jump with the 

 aid of their wings and their jumping legs to another 

 place, run a few steps, stop a second, draw up their jump- 

 ing legs and hop back into the grass. On beautiful eve- 

 nings the light on the porch will lure many of these. It 

 seems to blind them and holds them within the magic 

 circle of its rays. In the course of the Summer one 

 species follows hard upon the heels of another, this spe- 

 cies is predominant this month, another the next, and so 

 on throughout the hotter months of the year. But how 

 many of these tiny little fellows are hidden in the foliage 

 can scarcely be conceived. 



The grotesque form of the body of these minute cicada 

 is the result of a development which gives the body the 

 appearance of part of a plant, and the plant is necessary 

 for the life of this animal. The female bore with their 

 egg tubes, holes or slits into the twigs and lays their eggs. 

 Here the young develop and after casting ofT the outer 

 skin a number of times before they are fully developed, 

 they live upon the sap of these plants. Some of the ci- 

 cada form a white froth about them in the larvae stage. 

 These are the "spittle" insects. The froth consists of 

 plant sap which has passed through the body and is then 

 then shaken by the abdomen thus bringing in air which 

 is held as bubbles by the viscid quality of the liquid. In 

 no way does this froth protect the young larv;e, for various 

 wasps seek this froth, remove the larvse from this cover- 

 ing, and take it to their brood for food. 



THE WASHINGTON ELM 



(Co)ifiiiii,'ci from fnsc 695) 

 old. about sixty feet high and more than tlu'ee feet 

 through. 



There is another elm opposite the Senate oflicc build- 

 ing that is sixty feet high and about two and one-half feet 

 in diameter. This has eight cavities which were weaken- 

 ing the larger branches to an alarming degree — this case 

 was a serious one for the tree dentists. Treatment simi- 

 lar to that accorded the ash was prescribed for this fine 

 specimen. 



The Cameron elm is another of the trees having a touch 

 of romance. This stands on a knoll at the east side of the 

 Mouse wing of the ca]-)ilol. Its retention there required 

 the walks to lie built around its base, with space enough 

 left for the roots to take nourishment. This tree is about 

 ei.ghty years old. It has wide spreading branches and is 

 in good physical condition, but the wood of the large 

 branches in some cases was weak, necessitating bracin.g 

 with the galvanized strands. 



It is hoped by the capitol authorities that next year 

 Congress will make an appropriation large enough for 

 !klr. Davev to continue the work. — Florist ExclMni^c. 



