CHAPTER XXV 



TRIBE DIASPIDINI 



The Double-shielded Scales 



The body of the adult female is usually longer than broad, rare- 

 ly broader than long, frequently two or three times as long as broad. 

 The cephalic end is usually bluntly rounded and the caudal end is 

 often bluntly pointed and frequently provided with a pygidial incision. 

 The lateral margins are convex, the body is broadest through the 

 prothorax or the first abdominal segment, and the sides usually con- 

 verge caudad. The indentations marking the position of the coriae 

 between the thoracic and abdominal segments are usually distinct. The 

 lateral margins of the segments of the preabdomen are never provided 

 with bracteae either in the adult female or in the second nymphal 

 female, but often with plates. Lobes are usually present, rarely entire- 

 ly wanting. Plates are rarely absent, usually only in case the lobes 

 also are wanting, pectinae are rarely present and, if present, are repre- 

 sented by simple furcapectinae. The incisurae, except the median, are 

 usually narrow and filled by the plates. The median incisura is fre- 

 quently a pygidial incision and is usually without plates. Densariae are 

 never present, paraphyses are only rarely present and, when present, 

 are not typical in form. Altaceratubae are rarely, if ever, wanting; 

 they are arranged singly, rarely in pairs, their oraceratubae oval in out- 

 line, rarely twice as long as wide. Brevaceratubae are usually pres- 

 ent, generally numerous, frequently arranged in interrupted transverse 

 rows. Genacerores are usually present, usually arranged in five groups, 

 sometimes with seven or more and sometimes with only two, three, 

 or four groups. Mesogenacerores, when present, consisting of more than 

 eight cerores. Scale of the adult female coriaceous or filamentous, 

 usually whitish, sometimes grayish or brownish. Scale variable in form, 

 either round or nearly round with the two exuviae placed just within 

 the periphrey or projecting slightly or considerably beyond it; the scale 

 oval or pyriform or mussel-shaped in outline with the exuviae placed 

 at one end; or greatly elongated, six or more times as long as broad, 

 with the sides parallel. If pyriform, much longer than broad with both 

 sides convex or with one side convex and the other concave, and with 

 one end much smaller than the other. The two exuviae overlapping, 

 one on the end of the other, the first exuvia bearing the remains of 

 the antennae as porrect projectons. The female is rarely enclosed in a 

 puparium, but in a few species lives in galls and the lobes and plates 

 may be represented by pseudolobes. The scale of the male is elongate, 

 two or three times as long as wide, with the single exuvia projecting 

 beyond one end. The wax is usually opaque, white, or chalky in ap- 



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