Lgg-cases and early stages of some S. China Cassidide. 251 
excrement to the tip of each of the long posterior spikes, 
a telescopic movement of the last two segments of the 
body enabling it to perform this operation. As its size 
increases these pieces of excrement coalesce and form a 
roughly triangular lump. The cast skins are worked into 
the mass and held to form the “shield.” Up to the last 
instar the larva is yellow, then it changes to black, the 
white sporacles showing up distinctly. The size of the 
shield varies: sometimes it entirely covers the larva, at 
other times it leaves it half exposed. 
Both by egg-case and larval “shield” this species falls 
into the same division as the African genera Cassida and 
Laccoptera. 
4,—Cassida obtusata, Boh. 
The egg-cases of this species contain two eggs attached 
to the ordinary-shaped Cassidid egg-membranes. The 
case 1s bare, no excremental matter being placed upon it. 
The imago feeds upon Citrus trees and injures them 
considerably. 
Unfortunately we were not able to observe the larva, so 
cannot state the shape and nature of its appendages, but 
we anticipate that it is similar to Coptocycla circwmdata. 
The study of these interesting egg-cases and larval 
appendages naturally suggests the questions as to their 
origin and use. That they are a protection to egg and 
larva brought about by natural selection is the first 
solution that suggests itself. Were A. puncticosta the 
only species under consideration this might appear an 
adequate explanation, but after studying several African* 
and these China forms the authors are not satisfied with it. 
In A. puneticosta, where the egg-case is carried to its 
highest perfection, the eggs are as heavily parasitised as 
any that we have observed, and in Mozambique, ants eat 
into the case and destroy the eggs. In a similar manner 
ants destroy the eggs of Mantide. It is not an absolute 
protection that we look for, but only a relative one. To 
argue that this species would be exterminated were its 
ego-case less perfect appears illogical, for other species are 
just as abundant although their egg-cases are much less 
perfect. The wide range of this species we consider 
due to the, practically, uninterrupted growth of its food- 
plant, Zpomexa spes-caprex, along the African coast. It is 
* Trans, Ent. Soc,, 1904, pp. 1-19, 
