298 THE COCCIDAE 



pearance, rarely glassy and transparent. The surface is often more or 

 less distinctly tricarinate. 



There is a vague similarity about the general appearance 

 of the species of the tribe Diaspidini by which one who is familiar 

 with the species of the Diaspidinae is able to recognize them. 

 This appearance 'is common to the scales of the adult female and 

 of the male, the general form of the body of the adult female, 

 the pygidium, and the pygidial fringe. While there is this similar- 

 ity in appearance, yet it is too vague to define. The species that 

 belong to the tribe Diaspidini as listed in Fernald 's Catalogue are 

 about thirty. These are distributed among nine genera. 



The scale of the male is probably more typical for the tribe 

 than that of the female. They are generally quite similar in size, 

 shape, and appearance, elongate oval in outline with the two 

 sides parallel or subparallel with the caudal end bluntly rounded 

 and with the cephalic end rounded and bearing the single exuvia 

 which projects beyond the waxy portion of the scale and bears 

 the porrect remains of the antennae of the first nymph. The 

 dorsal surface of the secretionary portion is slightly or strongly 

 convex and may be uniformly convex or flat and faintly or strongly 

 carinate. The wax of the male scale is almost invariably opaque 

 white or chalky white. This chalky white appearance of the 

 male scales of many species is characteristic. It is a feature that 

 is emphasized from a habit of the males of certain species. At 

 certain times they congregate in immense numbers, in such num- 

 bers that a branch an inch in diameter for several inches or the 

 surface of an entire leaf may be completely covered by them. The 

 grouping together of such numbers of the chalky white scales 

 makes the branch or leaf very conspicuous even at a considerable 

 distance. 



The scales of the adult female of the different species are very 

 unlike in size, shape, and appearance, sometimes even among the 

 species of the same genus. They are of four types which inter- 

 grade more or less. In most species they are pyriform with the 

 two exuviae at the small end, the caudal and larger end is 

 broadly rounded with the sides slightly convex and strongly di- 

 vergent caudad. In a very few species the scale is very long, 

 eight or more times as long as wide, with parallel sides. When 

 the scale is mussel-shaped, which occurs in only a limited number 

 of species, it is curved with one margin convex and the other con- 

 cave. The surface of the mussel-shaped scales is usually more 

 or less transversely ridged as in an oyster shell. A third type 



