THE ANIMAL KINGDOM, 111 



The sting of an extremely small insect, the woolly aphis 

 {A2}Jris lunigera), which, when on the branches, would 

 elude the eye Averc it not enveloped in a tuft of white 

 wool, covers our apple-trees with numerous excrescences, 

 and these often end by killing it. 



The wounds inflicted hj insects also give rise to those 

 tufts of deformed, closely-set branches, which appear on 

 the trunks of the pine-trees, and to which the German 

 foresters give the name of tvitches' brooms; strange-looking 

 bunches, which the superstitious wood-cutters of the Hartz 

 fear to touch lest they should be struck by a thunderbolt, 

 for they believe these gTOwths attract the lightning. 

 They therefore call them also thimcler-lusJies} 



In the domain of the infinitely little the physiological 

 phenomena astonish us no less than the extreme slightness 

 of the motive organs! A single comparison will demon- 

 strate this. 



AVhen Ave communicate an elevating movement to our 

 arms, and suddenly bring them back to the body, a second 

 of time Avill scarcely suffice for the act; but, according to 

 the experiments of Herschel, some insects vibrate their 

 wings several hundred times in this short jDeriod ! 



^ The Chlorops lineata, a fly the name of -wliich indicates its yellow colours 

 barred with black, makes such havoc in the wheat fields, that those who have 

 followed up its history maintain that it would soon annihilate this cereal alto- 

 gether if its increase in numbers were not checked Vjy different cau.ses. Another 

 insect undertakes this task, and carries it out to a con.siderable extent; this is 

 Alysia Olivieri, which perforates the eggs of the Chlorops with its ovipositor, in 

 order to seeui'e a shelter for its own offspring. 



In the magnificent plates of Ratzeburg's work on the insects of the forest, 

 may be seen a representation of a forest quite deformed by the attacks of the 

 pine-twister. — liylophthires et lews Ennemis. Leipzig, 1842. 



Schacht, who has described the witch-brooms at full length, seems to attriljute 

 them to the stings of insects, which determine an exuberant flow of vital jxjwers 

 to the part where they have been inflicted. He says that these brooms, when 

 they are co%'ered with leaves, look, if seen at a distance, like a great mistletoe. 

 — Schacht, Les Arbres. Bruxelles, 1862, p. 140. 



