no Hemiptera-Homoptera. 



The autumnal individuals of gall.-ccola descend to 

 the roots, and there hibernate. 



Type Radicicola, or Root-inhabiting.— Oi this type 

 there are two forms : First, a degraded, or wingless 

 form; second, a perfect, or winged form. In early 

 spring the first form is developed from eggs laid in the 

 autumn, or from larvae that have hibernated. After 

 three or four generations of the wingless form have 

 been produced, the winged form makes its appearance. 

 Of this form there are both males and females. 



The injury done to the vine by radicicola is much 

 greater than that done by the gall-inhabiting type. 



Remedy. — No efficient remedy has yet been discov- 

 ered. (3, VI., 30). 



CocciD/E {Bark-lice^. 



The following well known species is described as an 

 illustration of the forms and habits of these anomalous 

 insects. 



The Oyster-shell Bark-louse of the apple, Mytilaspis 

 poinicorticis Riley (Aspidiottis conchiformis Gmelin). — 

 This insect is best known by the scale which it ex- 

 cretes. This scale is small, oblong, flattish, of an ash- 

 grey color, and shaped like an oyster-shell. It occurs 

 in great numbers on the bark of apple trees, and cov- 

 ers, during the winter and spring, a number of small, 

 round, white eggs. 



The eggs hatch in the latter part of May, or early 

 in June. 



The young louse is oblong-oval in form, one-hun- 

 dredth of an inch in length, and furnished with seven 

 jointed antenna;, and six legs. 



Note manner of excretion of the .scale. 



