450 



AN INTRODUCTION TO ENTOMOLOGY 



to a great extent by the introduction of an Australian lady-bug, 

 Roddlia cardindlis. 



Subfamily COCCIN^ 



The Cochineal Coccids 



This subfamily is of especial interest because it includes the 

 cochineal insect, Coccus cacti. This is a native of Mexico, but occurs 

 in the southern United States. It feeds upon various species of the 

 Cactaceae. It has been extensively cultivated in India, Spain, and 

 other countries. The adult female bears some resemblance to a 

 mealy-bug, but differs in lacking anal lobes and an anal ring. It 

 excretes a mass of white cottony threads, within which the eggs are 

 laid. The dye-stuff consists of the female insects, which, when mature, 

 are brushed off the plants, killed, and dried. The entire insect is used. 

 Cochineal is now being superseded by aniline dyes, which are made 

 from coal-tar. 



Subfamily ORTHEZIIN^ 



Fig. 525. — Orthezia, greatly 

 larged. 



The Ensign Coccids 



Members of this subfamily occur 

 not uncommonly on various weeds. 

 They are remarkable for the sym- 

 metrically arranged, glistening, white 

 plates of excretion with which the body 

 is clothed. Figure 525 represents a 

 nymph; in the adult female, the ex- 

 cretion becomes more elongated pos- 

 teriorly, and forms a sac containing 

 the eggs mixed with fine down. Later, 

 when the young are born, they excrete 

 a sufficient amount of the lamellar 

 excretion to cover them. In many 

 species the egg-sac is held in a more 

 or less elevated position; this fact 

 suggested the common name ensign- 

 coccids for these insects. Most of our 

 species belong to the genus Orthezia, 



Subfamily ERIOCOCCIN^ 



The Mealy-Bugs 



This subfamily includes many genera and species; the best -known 

 members of it are certain mealy-bugs, which are the most common 

 and noxious of greenhouse pests. These insects have received the 



