INSECTS. 



even on the roots of several different kinds of plants. The}- multiply rapidly, 

 and often prove as injurious as the most noxious plant -lice. The orange, 

 apricot, olive, peach, fig, and other fruit trees, as well as ornamental shrubs 

 like the rose, have each their own species, from which they sometimes suffer 

 severely. Some years ago the orange-plantations of California were threatened 

 with ruin owing to the ravages of Icerya purchasi, which had been accident- 

 ally imported from Australia, and had spread with great rapidity, Experts 

 were sent to Australia to try and discover the natural enemies of the insect 

 in its native country; it was found that the scale-insect was there kept in check 

 by dipterous and hymenopterous parasites, but chiefly by the larvae of a lady- 

 bird beetle. A number of these beetles and parasitic insects were brought to 

 America, and set to prey upon the Coccidcv. When they had multiplied sufficiently, 

 they were distributed amongst several orange-plantations, with the result that 

 many were soon almost entirely cleared of the scaly-bug. Though many species 



mm 



* 2 Y7\ 



COCHINEAL insect (Coccus cacti), with enlarged figures to the left of (1) the male and (2) female. 



of Coccidai have to be combated because of their injuries, there are a few which 

 are cultivated on account of the useful products they yield. Among these, the 

 cochineal insect {Coccus cacti) is a native of Mexico and other parts of Central 

 America, where it feeds on a species of cactus ; but it has been introduced into 

 Spain, Algeria, and a few other countries. The male is of a dark red colour, with 

 pale wings ; the female has a reddish brown colour, but her body, which shows a 

 distinct segmentation until the time of laying, is covered with a white powder. 

 About seventy thousand dried bodies of these insects, chiefly females, are said to be 

 contained in a single pound of cochineal. Long before the introduction of cochineal 

 into Europe, two native species of Coccidce had been used for similar purposes. 

 The dye with which the ancients produced their deep red or crimson colours was 

 obtained from Cermes vermilio, known to the Greeks as kokkos and to the 

 Arabians and Persians as kermes or alkermes. Another species (Porphyrophora 

 polonica), formerly known as the scarlet grain of Poland, is found in many parts 

 of Central Europe, and was at one time extensively collected for the sake of the 

 red dye it afforded. The lac-insect (Garteria lacca) of the Oriental countries, 



