160 THE COCCIDAE 



is frequently at the margin of the body a more or less distinct 

 indentation where the canellae terminate. These indentations are 

 the stigmatic clefts, also known as spiracular depressions or spirac- 

 ular grooves. The wax excreted by the spiracerores frequently 

 projects as a white powdery mass from the stigmatic clefts. The 

 lateral ends of the canellae are usually provided with large spine- 

 like setae which are located in the stigmatic clefts and serve to 

 keep the mouth of the canellae open. These setae, the spinae, also 

 known as stigmatic or spiracular spines or setae, vary greatly in 

 form and size from the marginal setae and are useful as characters 

 in identifying the species of this subfamily. The number of 

 spinae varies in the different species. There may be one, two, three, 

 four, five, or six in each stigmatic cleft. The great majority of 

 the species are provided with three spinae in each cleft. The 

 median one in such species is known as the median spina and the 

 others as lateral spinae. The median spina is usually much longer 

 than the lateral or all the others where there is more than three. 

 In some species the spinae are very short and broad, broader than 

 long, while in others they may be small pointed normal setae. 



The abdomen is usually convex-concave like the thorax. There 

 is no indication of segmentation in the adult female. The marginal 

 setae and marginal scales, when these latter are present, extend 

 around the margin of the abdomen. 



The most striking feature in the structure of the abdomen is 

 the deep mesal cleft or emargination, the anal cleft. The sides of 

 the cleft frequently overlap so that the cleft appears simply as 

 a longitudinal suture. In a few genera referred to this subfamily, 

 as Aclerda, the anal cleft is wanting. It is assumed that in such 

 cases the sides of the cleft have fused with a complete obsolescence 

 of the line of fusion. The length of the anal cleft varies somewhat 

 with the genus or species, it is generally about one-fourth to one- 

 fifth the length of the body, but in some cases, as Protopulvinaria, 

 it may be one-half or more of the total length of the body. In 

 those species deeply imbedded in wax as certain species of 

 Ceroplastes, the caudal portion of the body has been prolonged into 

 a prominent strongly chitinized horn or handle-like structure and 

 the anal cleft is located at the caudal end of the horn. This horn 

 is known as an opercularia. The length of the opercularia varies 

 not only with the species but with the depth of the wax excreted. 

 In those species where the amount of wax is considerable, the 

 opercularia is almost one-half the length of the body. It varies 



