INSECT SUCKERS AND BITERS. 207 
and branches of shrubs, looking like little lumps upon 
the stem, so that while the cuckoo-spit is protected 
by its froth the scaly plant-lice often escape by their 
likeness to the colour of the shrub on which they are. 
It is to these animals that the beautiful cochineal 
insect of Mexico belongs, and also the lac insect of 
India, which gives out the red lac used in the manu- 
facture of sealing-wax. 
Al! these are plant -suckers, and rarely move 
any distance from their home ; but there is another 
group which has learnt to run actively in search 
of food, of which some suck the juice of plants, 
while others have made use of their sharp lancet 
mouths to steal the blood of animals. These active 
suckers are the air-bugs and water-bugs; and though 
we dislike the name because one ugly wingless 
species haunts our own rooms when we do not keep 
them clean, yet many are very beautiful creatures. 
Look among the cabbages in the garden, and you 
will scarcely fail to find a pretty little red and black 
bug (P, Fig. 70) running over them, and piercing the 
leaves for their juice ; while a grey one with black, 
red, and yellow spots, is busy at work on the rasp- 
berry fruit. If you touch or frighten these plant- 
suckers, the disagreeable smell which they will give 
out from their bodies will suggest to you at once 
that they belong to the bug family. 
Then there are those curious thin-bodied insects 
which skim over the ponds in the summer, actually 
running on the top of the water, for which reason 
they are called " water- measurers" (m, Fig. 71), 
because their legs when stretched out seem to mea- 
sure off the water as they go along. These ghost- 
