110 THE COCCIDAE 



shaped plates. These plates are apparently limited to the 

 mesothorax, metathorax, and the first abdominal segment and may 

 be known as the mesal plates. 



There is a second series of plates which extend around each 

 margin of the body and form the lateral plates of the test. These 

 are the lateral plates or lateral pilacerores and are sometimes 

 designated as the marginal plates, the circumferential lamellae 

 the lateral plates, or the lateral keels. There are ten lateral 

 plates located on each side of the test. The first lateral plate of 

 each side is formed by a group of pilacerores located on the pro- 

 thorax. The other groups are located on the other thoracic 

 segments and abdominal segments one to eight. The pilacerores 

 forming the lateral plates are located on each lateral portion of 

 their respective segment adjacent to the band forming the ovisac 

 or the ventral plate. The abdominal spiracles of segments one tc 

 seven are located among the lateral pilacerores. The lateral 

 pilacerores of the eighth segment are frequently continuous on the 

 meson so that the pair of plates of this segment is usually repre- 

 sented by a single plate and in such cases it is frequently designated 

 as the telson. It is located caudad of the anal plate and for this 

 reason has been named the postanal plate. The plates formed by 

 the groups of lateral pilacerores on segments five, six, and seven 

 are frequently much larger and longer than any of the others and 

 have been designated the caudal plates. They are also apparently 

 the posterior lateral plates of some writers. 



In a few species there is a longitudinal row of plates on each 

 side between the mesal plates and the lateral plates. These have 

 been named the intercalary plates. Newstead designated them the 

 supplementary scales. In some descriptions the so called sub- 

 dorsal keels or plates may be homologous with the intercalary plates. 



The subfamily Ortheziinae contains six genera which can be 

 separated by means of the following table : 



GENERA OF ORTHEZIINAE 



a. Antennae of adult female with seven to nine segments and of 

 nymphal female with six segments; tibio-tarsal sutures of each leg 

 distinct, 

 b. Antennae of adult female with nine segments; head of adult 



male with three ocelli. Douglasia MacG. 



bb. Antennae of adult female with seven or eight segments and of 

 nymphal female with six segments; head of adult female with 

 two ocelli or ocelli wanting. 

 c. Adult female without mesal plates. Orthezia Bosc. 



