HEMIPTERA. 



171 



this country; and Figure 211, the hemispherical scale, 

 Lecanium hemispharicum (hem-i-sphaer'i-cum), which occurs 

 in conservatories everywhere, and in the open air in Cali- 

 fornia. 



The Armored-scales Sub-family ZTzas/ft'%? (Di-as-pi'nae). 

 The great majority of the common scale insects of this 



FIG. an. Lecanium hemisphcericum ; 3^, insect enlarged. (From the Author's Report 

 for 1880.) 



country differ from the forms described above in that the 

 body of the insect, except for a very short period after 

 birth, is covered with a scale composed in part of an excre- 

 tion of the insect and partly of molted skins. Thus in the 

 Lecaniums the scale-like object is the body of the insect; 

 but in the case of the Oyster-shell Bark-louse, the Pernicious 



