SC ve 
so forth. All these characters are valuable in classifica- 
tion, and are best observed in the living insects. The 
species of the subfamily Diaspinae form quite distinct 
scales, in which they live like an oyster in its shell. 
The cast skins of the two immature stages are retained 
on the top of the scale or at one end, and are shown 
in the accompanying figure of Aspidiotus sacchari, CklL., 
a species (not before figured) found on sugar-cane in 
Jamaica. It will be noticed in the same figure that the 
male scale is much smaller and of a different shape from 
that of the female. It really represents the first and sec- 
ond skins of the female, rather than the true scale, 
although in this species the texture of the male scale is 
like that of the female. 
When the external characters have been noted, it is 
necessary to boil some of the specimens in a solution 
of caustic potash (liquor potassae), which renders them 
transparent, so that they can be studied hy transmitted 
light under the compound microscope. Then the leges 
and antennae, the mouth-parts, and the different hairs 
and bristles on the body, when present, have to be des- 
cribed. It is especially important to state the number or 
joints in the female antennae, and the relative lengths 
of the several joints. With the Diaspinae, the adult fe- 
males of which lack legs and antennae, the hind end of 
the body, as here figured (for the first time) in Aspidiotus 
mangiferae, Ckll., 1s to be described minutely. The stu- 
Ci tgs 
(tt @ 
> Ko 
oS} NSE 
B. A 
Aspidiotus sacchari Ckll. 
A female scaie ; B male scale. 
