218 



NATURAL lilsrORY OF ARTHROPODS. 



The insect which constitutes the cochineal is an unattractive jjlump, oval, (.lull 

 purplish-brown object, about an eiglith of an inch in Icuntli, cuvereil, when alive, with a 

 cottony secretion which hitles 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 dark, smooth eyes, and two ocelli. liis antennre are com- 

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



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

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



-Coccus cacti, coohiiieal; ((, living on oaclns {Ojncritia); b, male; c, fenuile. 



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

 02nintia coccuiilifera, which is cultivated expressly for the purpose of feeding and 

 developing- the insect. Such (piantities 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. Euglaud alone 

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

 is also not uucomuion ujion wild cacti in Texas and Florida, and 

 occasionally may be found upon tliese plants in our hothouses. 



Many other remarkalile forms belong to this extensive family, 

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

 Gossi/pan'a inaiinlpara of Mount Sinai, and other parts of Arabia, 

 wliich gi-^es rise to tlie 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 

 [lellets, and is then gathered and packed for transportation. 



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

 lives bteneath 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 imtives for 

 necklaces, and is accordingly arranged on threads like strings of 

 Ijeads. The original describer of this species called it 2Iargarodes 

 fwmicaniin, in allusion to its pearly appearance and habit of 

 living in company with ants. 



A third is the anomalous genus Ort/iezia, which inhabits both Europe and the 

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



I'lG. L'a7.— I'OCCUS 

 adonidam. 



