THE COCCIDAE 



CHAPTER I 



INTRODUCTION 



The subdivision of the body into a series of somewhat similar 

 rings or areas and the modification of the external surface of the 

 rings into a hardened skeleton or cuticle are important character- 

 istics. They denote that any animal possessing them is an 

 Arthropod. The rings, known as segments, are separated by dis- 

 tinct constrictions or infoldings. A portion of each infolded 

 portion, known as a conjunctiva or coria, is generally different in 

 color and more flexible. The presence of a pair of segmented 

 appendages on each or a few of the segments is a further indi- 

 cation of an arthropodan relationship. The fact that the segments 

 are assembled into three groups or regions, a cephalic region or 

 head which is apparently unsegmented but in reality consists of 

 six segments, an intermediate region or thorax consisting of three 

 segments, and a caudal region or abdomen consisting typically of 

 eleven segments, is an indication of an affinity with the hexapods 

 or insects. This relationship is usually emphasized by the presence 

 of a pair of legs on each segment of the thorax, the absence of legs 

 on the abdomen, and the modification of the appendages of the 

 segments of the head into mouth-parts. The evidences of relation- 

 ship of coccids to arthropods and insects are in part wanting in 

 many coccids and are all wanting in some. 



The insects of the order Hemiptera, to which the family Coe- 

 cidae belongs, possess typically the following characteristics. The 

 constriction between the head and prothorax, the procoria, is dis- 

 tinct. The coria between the prothorax and mesothorax, the meso- 

 coria, is also distinct, while the one between the mesothorax and 

 metathorax, the metacoria, as well as the coria between the met- 

 athorax and the first abdominal segment, the unacoria, are usually 

 more or less obscure. The head bears a pair of compound eyes, 

 a pair of antennae of varying size and shape, and three pairs of 

 mouth-parts. These latter are of the sucking type. Two of the 



