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TEXT-BOOK OF ZOOLOGY 



6. Small insects, May flies, etc., are no sooner spied than they are 

 seized. Here, again, the great mobility of the head is brought into 

 play. The actual organ of prehension is the peculiarly-constructed 

 labium, which, in conjunction with the labrum, almost completely covers 

 the remaining mouth parts. It consists of three portions, of which the 

 two large lateral ones form the blades of a pair of nippers. While 

 consuming its meal, the dragon-fly sits on a reed stalk or similar object, 



usingits sharply-toothed mandibles 

 and maxillae for tearing the prey, 

 which is held fast by 



7. The fore-legs. These limbs, 

 owing to the prothorax not coalesc- 

 ing with the other thoracic somites, 

 are moved with much greater free- 

 dom than they would be otherwise 

 (see p. 340). Apart from this, the 

 legs are only used for clinging on 

 to objects; they remain, therefore, 

 very weak and light, which cir- 

 cumstance, again, influences the 

 flight capacities of the insect. 

 (Compare with swallow, butterfly, 

 and other good fliers.) 



8. The dragon fly frequents the 

 vicinity of water for two reasons : 

 first, because it there finds a teem- 



Head of Larva of Blue Dragon Fly (viewed in § multitud 6 of gnats and other 

 from Below). (Much magnified.) vermin, and, secondly, because 



I., With mask folded up; II., with the same Q TiJk, f fiT nnlA donnaifa it a „„„„ 



unfolded. A., Eyes; F„ antenme ; 01., "' H6 Iemale deposits its eggs 



labrum; Ok., mandibles; Uk:, maxillae; upon Water-plants. For this pur- 



Ul., labium, having the form of a mask ; 1 „„„. v._ „_„„„„ „* .. , 



and 2, its two elongated portions; 3, the P 0S6 > b y m eans Of an Ovipositor (see 



pincer-shaped portion. ichneumon flies) upon the penul- 



timate and antepenultimate 

 somites, the insect pierces the stalk of the plant below the surface of the 

 water, and in each puncture deposits an egg. (Other Libellulidaa simply 

 drop their eggs into the water.) At the end of the abdomen there are 

 two further processes forming a small pair of pincers, with which the 

 male may be frequently observed clasping the female. 



