177 



CHAPTER VIII. 



SUCKING INSECTS. 



WE have elsewhere remarked that, " the beak 

 (haustellum) of an aphis is no more fitted for lap- 

 ping honey-dew, than the bill of JSsop's crane was 

 for eating out of a shallow plate*." The mere in- 

 spection of one of these insects with a pocket mag- 

 nifier will be sufficient to demonstrate the position ; 

 but, for the sake of illustration, we shall give a few 

 details, and for that purpose we shall select the 

 brown aphis of the oak (Aphis Quercus, LINN^US), 

 in which, from its being much larger than its con- 

 geners, the parts are more conspicuous. The sucker 

 in this insect is much longer than the body, and, 

 when unemployed, is carried between the legs close 

 to the belly, extending behind the insect, like a tail 

 slightly curved upward. The instrument consists of 

 a transparent tube, terminating in a hole so minute, 

 that Reaumur could not discover it with his most 

 powerful microscopes, but easily proved its existence 

 by pressing out from it a drop of fluid. By means 

 of pressure, also, he could render more obvious two 

 instruments of a brownish colour contained in the 

 sucker, and which he conjectured to act like the 

 piston of a pump ; though from their minuteness this 

 could not be correctly ascertained. We might suppose 

 them to act as perforators, were it not that the point 

 of the sucker itself seems sufficiently adapted to that 

 purpose. The figures which we have here given 

 will render our description easily understood. 

 * Insect Transf. p, 18. 



