596 



HEMIPTERA-HOMOPTERA 



CHAP. 



however, continues development ; notwithstanding the impossi- 

 bility of taking food, owing to the absence of a mouth, it increases 

 much in size, and the organs of the future perfect Insect 

 commence to develop from imaginal discs in a manner similar to 

 that which occurs in the Dipterous genus Corethra ; no mouth- 

 parts are however developed, these being merely represented by 

 spots of pigment, or rudimentary additional eyes. The wings 

 are developed outside the body. Difference of opinion prevails as 

 to the nature of the instars between the vouncj larva and the 



V O 



imago. It is clear, however, that Fig. 291, D, corresponds fairly 



a 



i " 



4 1 



< 



FIG. 29i. Development of male of Aspidiotus nerii. A, Newly hatched larva ; B. 

 prae-pupal instar ; C, pupa before ecdysis ; D, pupa shortly before the emergence 

 of the imago : a, antenna ; e, eye ; /, wing-rudiment ; /, leg ; 0, basal part of 

 mouth-organs. (After Schmidt. ) Magnification not definitely stated. 



with the pupa of Insects with complete metamorphosis, and the 

 instars shown in Fig. 291, B, C, may therefore be looked on as 

 equivalents of the resting-larva stage of ordinary Insects with 

 complete metamorphosis. Witlaczil considers this development 

 to be a condition of incomplete, approaching very nearly to 

 complete, metamorphosis. The condition is perhaps more pre- 

 cisely estimated if we recollect that winged Insects are divided 

 into two series, in one of which the wings are developed outside 

 the body ; in the other, inside the body. The Insects with very 

 complete metamorphosis all belong to the second of these two 

 series, while in the male Coccid we have the highest form of 

 metamorphosis attained by any of the first series. As regards 

 the development of the female encysted nymph or pupa, 

 previously alluded to as being found in the " ground-pearls " of 



