298 STATES OF INSECTS. 



Reaumur found to depend upon the expansion of the 

 previously compressed segments of the animal by means 

 of the included air a . Both in this instance and in that 

 of insects whose wings only require expansion, the size 

 of the imago often so greatly exceeds that of the pupa, 

 that we can scarcely believe our eyes that it should have 

 been included in so contracted a space. The pupa of 

 one of the beautiful lace-winged flies (Hemerobius Perla) 

 is not so big as a small pea, yet the body of the fly is 

 nearly half an inch long, and covers, when its wings and 

 antennas are expanded, a surface of an inch square b . 



When the development of the perfect insect is com- 

 plete, and all its parts and organs have attained the re- 

 quisite firmness and solidity c , it immediately begins to 

 exercise them in their intended functions; it walks, 

 runs, or flies in search of food ; or of the other sex of its 

 own species, if it be a male, that it may fulfill the great 

 end of its existence in this state — the propagation of its 

 kind. Previously to thus launching into the wide world, 

 or at least immediately afterwards, almost all insects dis- 

 charge from their intestines some drops of an excremen- 

 titious fluid, often transparent, and sometimes red. I 

 have before related to you the alarm that this last cir- 

 cumstance has now and then produced on the minds of 

 the ignorant and superstitious d . Whether this excre- 



a Reaum. iii. 378. b Ibid. 385. 



c Insects of the beetle tribe, especially such as undergo their me- 

 tamorphosis under ground, in the trunks of trees, &c, are often a 

 considerable time after quitting the puparium before their organs 

 acquire the requisite hardness to enable them to make their way 

 to the surface. Thus, the newly-disclosed imago of Cetonia aurttta 

 remains a fortnight under the earth, and that of Lucanus Cervus, ac- 

 cording to Rosel, not less than three weeks. 



,J See above, Vol, I. p. 34 — . 



