THE OPEN TYPE OF WING -GROWTH 89 



long and flexible, may be driven deeply into the plant-tissues. 

 After a period during which it walks about with fair activity, 

 the larva fastens itself by its piercers and remains quiescent, 

 a protective waxy secretion forming over the body, white, 

 diffuse and thread-like in the mealy-bugs, but reinforced with 

 the cast cuticle and hardening into the characteristic shield- 

 like scale in the typical scale-insects (Fig. 49). Beneath this 

 the young male (Fig. 49 d) passes into a second larval form 

 without feelers or legs, 1 but rudiments of these as well as of 



\ 



FIG. 48. MUSSEL SCALE-INSECT (MytUaspis pomorum). 



a, male (dorsal view); c, nymph; e, female (ventral view), x 40. b, Foot 

 of male ; d, feeler of larva . Highly magnified. From Howard, Year Book, U.S. A. 

 Dept. Agric., 1894. 



wings are prepared in the underlying body-wall, to appear 

 outwardly in the next stage of the life-history, the so-called 

 ' pupa " which remains still beneath the shelter of the scale 

 until the fully developed, winged adult emerges, breaking 

 through both pupal cuticle and scale to the enjoyment of its 

 short existence as a flying creature of the air. 



1 E. O. Schmidt : " Metamophose und Anatomie des mannlichen 

 Aspidiotus nerii ". Arch. f. Naturgesch., LI. 1885. 



