144 



AN INTRODUCTION TO ENTOMOLOGY. 



the fact that the adult female excretes a large cottony mass in which 

 the eggs are laid. Fig. 127 represents Pulvindria innumerdbilis, 

 which is common on grape, maple, osage orange, and other' plants. 



Ceropldstcs. — The species belonging to this genus are furnished 

 with a thick covering of waxy material, which does not, however, 

 adhere closely to the insect. Only two species have been found in 

 the United States. Both of these are Florida insects, and in each the 

 waxy covering is dirty-white in color. The most common species, 

 C. Floridensis (Fig. 128), infests a great variety of plants both wild 

 and cultivated. C. cirripediformis (Fig. 129) is not very common ; 

 it infests orange and quince. It is a beautiful species, as the waxy 

 excretion is in the form of regular-shaped plates. 



Sub-Family III.— DlASPlNiE* 



The Diaspince includes those species of scale-insects that form a 

 scale composed in part of moulted skins, and partly of an excretion of 

 the insect. This apparently trivial character is correllated with im- 

 portant structural characters, which mark a well-defined group. The 



Fig. 130. — Organs of the last segment of adult females of the Diaspina. a, opening of oviduct ; 

 />, anus ; d, d, ccphalo-lateral groups of spinnerets ; e, e, caudo-lateral groups of spinnerets ; /', 

 lobes ; k, spines ; /, plates (these are frequently described by authors as spines). (From a Report 

 by the Author, 1881.) 



most important of the structural characters is the peculiar form of 

 the last segment of the body. This segment is highly specialized 

 for the excretion and manipulation of wax. It is furnished with 

 many openings and appendages. These vary greatly in number and 

 form, and afford good characters for distinguishing closely allied 



* Diasplnse, Diaspis: dia (did,) through; aspis (acritis), a shield. 



