CLASS I. INSECTA: ORDER 10. RHYNCHOTA. 595 



for the same purpose. The Mexican CocniNEAL, Coccus cacti, which has driven the others out 

 of the field, is also a species belonging to this group. It lives as a parasite upon the Nopal, 

 or Cactus opuntia — a plant very common in Central America. The commercial importance of 

 this insect is shown by the fact, that in 1850 no less than two million five hundred and fourteen 

 thousand five hundred and twelve pounds of cochineal were imported into Great Britain alone; 

 and as about seventy thousand insects are supposed to be contained in a pound of this substance, 

 we may form some idea of the numbers annually destroyed. For many years the cultivation of 

 cochineal was entirely confined to Mexico ; but the insect has lately been introduced into Spain 

 and the French possessions in Africa, with some prospect of success. 



A fourth species, of great importance, is the Lac Insect, C. lacca, an inhabitant of the East 

 Indies, where it feeds upon the Banyan-tree, J^'icus religiosa, and some other tiees. To this 

 insect we are indebted, not only for the dye-stufi"s known as lac-dye and lac-lake, but also for the 

 well-known substance called shell-lac, so much, used in the preparation of sealing-wax and varnishes. 

 In all these cases it is only the female insects that yield the coloring matter. 



THE PHYTOPHTHIRIA. 



The gi'eater part of this tribe is composed of Aphides or Plant-Lice, whose extraordinary history 

 renders them one of the most interesting groups of insects. They are all small animals, with a 

 more or less flask-shaped body, furnished with six feet and a pair of antennae, and usually with 

 a pair of short tubes close to the extremity of the abdomen, from which a clear sweet secretion 

 exudes. Both sexes are sometimes winged, sometimes apterous; and the individuals of the same 

 species are often winged and apterous atdiff'erent periods of the year. They all live upon plants, 

 the juice of which they suck; and when they occur in great numbers, often cause great damage 

 to vegetation. Gardeners and farmers are well aware of this. Many plants are liable to be 

 attacked by vast swarms of Aphides, when their leaves curl up ; they grow sickly, and their 

 produce is certain to be greatly reduced. One striking instance is presented by the Hop-Fly, 

 Aphis liumuli, which in England alone has often done damage to the hops to the extent of 

 millions of dollars, in a single year. 



The sweet fluid which exudes from the tubular process of the abdomen of these insects is often 

 in such abundance that it drops upon the leaves of the plants frequented by them, and even to 

 the ground. It is well known by the name of honey-dew. Ants have a particular fondness for 

 this fluid, and may constantly be seen upon trees and plants frequented by Aphides, stroking 

 them with their antennae, apparently to induce them to furnish a supply of the coveted fluid. 

 From this circumstance the Aphides have been termed the Arifs Milch- Cows ; and they are said 

 to tend them with as much care as would be bestowed by a human farmer upon his cattle. Wasps 

 also have been observed similarly engaged. The manner of propagation of these insects, which 

 we have noticed in our Introduction to this Class, p. 539, is extremely curious, and has been the 

 subject of immense research on the part of naturalists. 



THE CICADARIA. 



Nearly allied to the plant-lice are the Cicadaria, which include a great variety of insects, of 

 which the Common Frog-Hopper of Europe, Aphrophora spumaria, is an example. This is a 

 small insect, furnished with long hind-legs which enable it to perform most extraordinary leaps. 

 The Tree-Hoppers of this country, Membracidoe, of which there are several species, arc small, 

 mostly green, and take leaps of five or six feet. 



The family of Fulyorina includes the Lantern- Flies, of which a large species inhabiting Guiana, 

 the Fuhjora laternaria, is said to emit considerable light in the dark. This light is produced from 

 a singular prolongation of the head, which is common to this and many other species, exhibiting 

 most extraordinary forms in some instances. A well-known example of the genus Fulgora is 

 the F. candelaria, constantly to be seen in boxes of Chinese insects. Many of the Fulgorina are 

 of a large size, and decorated with most brilliant colors ; but they are all inhabitants of warm 

 climates. The European species are small, and generally very dingy in their appearance. 



The Stridulantia derive their name from the faculty they possess of producing a chirping 



