196 



APHIDES, SCALE INSECTS, ETC. 



The perfect insect of the Corn Thrips (Fig. 151, 1 

 to 4) is blackish, but in the first state of larva or grub 

 it is of a deep yellow ; in the second it is of a paler 

 yellow, with whitish wing-cases. 



These Thrips are to be found from June onwards 

 in the growing "Wheat ears, and sometimes in the 

 sheathing leaves of the stem. They feed on the corn 

 grain, by piercing into it with their sucker-like jaw 



Pig. 151. — 1 to 4, Corn Thrips ; 5 to 8, Potato Thrips and larva : 

 nat. size and magnified. 



apparatus,* and thus draw away the juices and cause 

 the grain to shrivel. 



Another kind, also figured above, infests the Potato, 

 drawing away the juices in the same way as the Corn 

 Thrips ; as do also the Aphides, Scale insects. Plant 

 Bugs, and some others, which we have just noticed, 

 with their variously formed sucking apparatus. In the 

 ease of the Potato Thrips, dusting with dressings of 

 lime and soot, or other mixtures, might do good ; but 

 for the Corn Thrips it seems impossible to find any 



* The precise character of the mouth of this insect has been much 

 discussed. The result appears to be, that though it is shown to feed 

 by suction, yet that it has a pair of long bristle-like mandibles (see 

 Introd. to ' Classification of Insects,' by J. O. Westwood, vol. ii., p. 

 2). I have therefore in the list of orders, page 23, placed " Thrips," 

 Tliysanoptcra, amongst the Insects with jaws. 



