PACKAui..] IXSECTS OF THE PLANT HOUSE. 



Ill 



form of the true scale insects (Fig. 75, enlarged) that the 

 female Metriy bug is but little more advanced in organization 

 than these larvje, though greatl}' exceeding them in size. 

 The male meal}' bug {Coccus adonkhiin Linn.) is like the 

 male scale insect (Fig. 76, enlarged), and still more nearly 

 resembles that of the cochineal, Avhicli is two-Avinged, with 

 two long caudal wax}- threads. While the female Coccus 

 undergoes no transformations, the male does, spinning a 

 cocoon. Here we have a wonderful difference in form and 



Fig. 7G. 



Pine Scale Insect, male. 



habits ])ct\vccn the sexes, the female attaining the adult state 

 b}' simple increase in size of the larval form, while the male 

 passes through a well marked metam()ri)hosis. This shows 

 conclusively that metamorphosis is an accjuired mode of 

 growth. Tlie Coccus is a tenth of an inch long, covered with 

 a white, cotton}', mealy substance. The young are rather 

 narrower than the old ones. The latter when about to lay 

 its eggs, adheres by the long, slender beak to the surface 

 of the leaf, and secretes from the abdomen a large cottony 

 mifss of fine particles of wax, which surrounds and partially 



15 



