454 



AN INTRODUCTION TO ENTOMOLOGY 



several of which are found in the southern United States; the follow- 

 ing will serve as an example of these beautiful insects. 



The barnacle scale, Ceropldstes cir- 

 ripediformis. — Several individuals of 

 this species are represented natural size, 

 and one enlarged, in Figure 532. It 

 infests orange, quince, and many other 

 plants. 



Subfamily KERMESIIN^ 



The Pseudogall Coccids 



This subfamily includes only one 

 genus, Kermes. Species of this genus 

 are common on oaks wherever they 

 grow. These insects are remarkable 

 for the wonderful gall-like form of the 

 adult females. So striking is this re- 

 semblance, that they have been mis- 

 taken for galls by many entomologists. 

 Fig. 533 represents a species of this 

 genus upon Qtiercus agrijolia. The gall- 

 like bodies on the stem are adult fe- 

 males, the smaller scales on the leaves 

 are immature males. 



Subfamily DIASPIDIN^ 

 The Armored Scales 



Fig. 532. — Ceroplastes cirripedi 

 formis. 



The Diaspidinas includes those coc- 

 cids that form a scale, composed in 

 part of molted skins and partly of an excretion of the insect, beneath 

 which the insect lives. It is on account of this covering that these 

 scale-insects are named the armored scales. The Diaspidinae are also 

 characterized by a coalescence of the last four abdominal segments 

 so as to form what is known as the pygidium ; this peculiar structure 

 is described on an earlier page. 



The formation of the scale begins immediately after the close of 

 the active period of the first m-mphal instar. At this time the young 

 insect settles and begins to draw nourishment from its host. Soon 

 after, there exude from the body fine threads of wax, the commence- 

 ment of the formation of the scale. At the close of the first stadiimi, 

 the molted skin is added to the scale and forms a part of it. This is 

 also true, except as noted below, of the second molted skin of the 

 female (Fig. 534, 2b and 2c). In the formation of the scale of the 

 male only the first molted skin is added to the scale (Fig. 534, 2d). 

 The scales of males can be distinguished by this fact, and, too, they are 

 much smaller than the scales of females. 



