Sn BE 
plants than wild ones, and appear to abound more at 
sea-level than in the mountains. 
When making a study of them, with aview to de- 
scribing new species, it is necessary to become acquainted 
with the species of every country, because those of one 
country so frequently appear in another. The natural 
range of the species seems to be usually quite small, or 
at any rate confined to one of the primary zoological 
regions (1), but these insects are continually being carried 
from country to country on plants, and that is why 
their range becomes so wide. For example, Zecanium man- 
giferae, Green, described from Ceylon, is now found in 
the West Indies ; Diaspis anvygdali, Tryon, described from 
Australia, is found in Ceylon, Japan, the West Indies 
and North America. 
The number of students at present engaged upon 
the Coccidae, is not sufficient to deal with the material 
coming to hand, although several workers are quite in- 
dustrious. Not only are new students wanted, but more 
especially observers in little-worked localities, who will 
study the habits of the species, their food-plants, para- 
sites, and so forth. The writer is every day more con- 
vinced that no branch of zoological science can be put 
ona thoroughly sound footing until we know the relation 
of the species as they exist in nature, not merely as 
they may be found in museums or entomological cabinets. 
In describing a Coccid, one has to take note of the 
colour, shape, size, and so forth, and especially of the 
nature of the scale, or any woolly or cottony covering 
there may be. Thus the mealy-bugs ( Ductylopius ) are 
furnished with hairs which usually support little masses 
of white secretion. Sometimes, in this way, a species 
will have white filaments at the tail and along the sides, 
sometimes only at the tail, sometimes none at all, and 
(1) There are some few apparent exceptions. Thus, Mr. Maskel! 
believes (in litt.) that Tachardia decorella, Mask., is native both 
in Australia and India. 
