2G0 TROPICAL INSECTS DIRECTLY USEFUL TO MAN 



castor-oil plant {Ricinus communis), spins remarkably soft 

 threads, which serve the Hindoos to weave tissues of uncom- 

 mon strength. 



In America there are also many indigenous moths whose 

 filaments might be rendered serviceable to man, and which 

 seem destined to great future importance, when trade, quitting 

 her usual routine, shall have learnt to pry more closely into 

 the resources of Nature. 



While the Cocci, or plant bugs, are in our country deservedly 

 detested as a nuisance, destroying the beauty of many of our 

 garden plants by their blighting presence ; while, in 1843, the 

 Coccus of the orange trees proved so destructive in the Azores 

 that the island of Fayal, which annually exported 12,000 chests 

 of fruit, lost its entire produce from this cause alone, two tro- 

 pical members of the family, as if to make up for the misdeeds 

 of their relations, furnish us — the one with the most splendid of 

 all scarlet dyes, and the other with gum-lack, a substance of 

 hardly inferior value. _ 



The English gardener spares no trouble to protect his hot and 

 greenhouse plants from the invasion of the Coccus hesperidum ; 

 but the Mexican haciendero purposely lays out his Nopal plan- 

 tations that they may be preyed upon by the Coccus cacti, and 

 rejoices when he sees the leaves of his opuntias thickly strewn 

 with this valuable parasite. The female, who from her form and 

 habits might not unaptly be called the tortoise of the insect 

 world, is much larger than the winged 

 male, and of a dark-brown colour, with 

 two light spots on the back, covered with a 

 white powder. She uses her little legs 



fn' only during her first youth, but soon she 



/ \ sucks herself fast, and henceforward re- 



' * mains immovably attached to the spot 



she has chosen, while her mate con- 

 tinues tq lead a wandering life. While 

 thus fixed like an oyster, she swells or 

 Cochineal. grows to such a sizc that she looks more 



like a seed or berry than an insect ; and 

 her legs, antennae, and proboscis, concealed by the expanding 

 body, can hardly be distinguished by the naked eye. Great care 

 is taken to kill the insects before the young escape from the 



