218 



NATURAL HISTORY OF ARTHROPODS. 



The insect which constitutes the cochineal is an unattractive plump, oval, dull 

 purplish-brown object, about an eighth of an inch in length, covered, when alive, with a 

 cottony secretion which hides the rings of the body. When dead and dry this cottony 

 substance rubs off and leaves only vestiges in the form of whitish powder. It is the 

 female only that is so constituted ; for the male is a smaller, slighter, gay red insect, with 

 a pair of whitish wings, four dai'k, smooth eyes, and two ocelli. His antennae are com- 

 posed of ten joints each, and the two at the base are armed with one or two little bristles. 



This species was first discovered in Mexico and was carried thence to Spain, and 

 by the French introduced into Algiers, where extensive uopalries have been established 



FIG. 296. Coccus cacti, cochineal; a, living on cactus (Ojmntia); b, male; c, female. 



for its cultivation. It swarms upon several kinds of Cacti ; but especially upon the 

 Opuntia coccinilifera, which is cultivated expressly for the purpose of feeding and 

 developing the insect. Such quantities of the cochineal insects are produced in Mexico 

 and Peru that Humboldt estimated the amount annually brought to Europe to exceed 

 800,000 pounds, each pound containing about 70,000 of these insects. England alone 

 has been known to consume in a single year 150,000 pounds, valued at 375,000. It 

 is also not uncommon upon wild cacti in Texas and Florida, and 

 occasionally may be found iipon these plants in our hothouses. 



Many other remarkable forms belong to this extensive family, 

 but we can only mention two or three more. One of these is the 

 Gossyparia mannipara of Mount Sinai, and other parts of Arabia, 

 which gives rise to the manna of commerce. This it does by punctur- 

 ing the tender shoots of the tamarix tree, causing an exudation of 

 sweetish gum which, when hardened, drops to the ground in small 

 pellets, and is then gathered and packed for transportation. 



Another is the curious " Ground Pearl " of the Bahama Islands. It 

 lives beneath the soil in crevices frequented by ants, and acquires a 

 shell-like, calcareous scaly covering, which has caused it to be mis- 

 taken for the outer case of a mollusk. It is used by the natives for 

 necklaces, and is accordingly arranged on threads like strings of 

 beads. The original describe!* of this species called it Margarodes 

 formicarum, in allusion to its pearly appearance and habit of 

 living in company with ants. 



A third is the anomalous genus Orthezia, which inhabits both Europe and the 

 United States. It is composed of four species of insects, ranging from about one- 



FlG. 297. Coccus 

 adonidum. 



