The fine cochineal differs from the wild one, not in size, hut also in being mealy and covered with a white powder, while the wild one is enveloped in a thick cot ton, which prevents its rings from being distinguished ; but the metamorphoses of the two insects are the same. In those parts of South America where for ages the wild cochineal has been reared, it has never yet lost its down. It is true, that in the nopaleries established by M. Thiery at St Domingo, it was thought to be observed, that the insect under the care of man increased in size, and under went a sensible change in the thickness of its cotton covering ; but M. Latreille, who is inclined to look upon the wild cochineal as a different species from the fine one, believes that this diminution of down is merely ap parent, and that it must be attributed to the thickness of the body of the insect. The rings on the back of the female being more dilated, the hairs covering this part must appear less close, and consequently clearer. Hum boldt was informed by several persons who had long lived in the neighbourhood of Oaxaca, that sometimes among the small coccus recently brought into the world, indi viduals are observed covered with very long hair. But it must not he forgotten, that the fine cochineal, on leav ing the body of the mother, is wrinkled in the back, and covered with twelve silks frequently very long, which disappear when it becomes adult. Those who have not attentively compared the offspring of the fine cochineal, with that of the wild cochineal, are naturally struck with the presence of these hairs. The fine cochineal appears powdery ten days after its birth, when it frees itself from its fringy dress of small silks, whereas the wild cochineal is more and more covered as it gets older, its down thickens, and the insect resembles a small white flake, at the period which precedes the conjunction of the two sexes.
It is sometimes observed in the nopalerics of Oaxaca, that the winged male of the fine cochineal couples with the female of the wild cochineal. This fact has been cit ed as an evident proof of the identity of the species ; but we commonly see in Europe coccinelles couple together, essentially different in their form, shape, and colour.
When tvw species of insects at c ra the same \ we ought not to be astonished at their coupling toge ther.
M. Tillery thought himself warranted in maintaining, that the fine cochineal and the plant on which it feeds, are both found wild in Mexico, and that the insect and the nopal of the plantations of Oaxaca, have been insen sibly modified in their form by means of long culture. This supposition, however, appears equally gratuitous with that which would pronounce grain, maize, and the banana, to be degenerated plants. The coccus cacti has an infinite number of enemies among the insects and birds. Wherever the cotton cochineal propagates of itself, it is not to be found in any abundance, from which we may easily conceive that the mealy cochineal must have been still more rare in its native country, because it is much more delicate, and not being covered with down, is more sensible to the cold and humidity of the air. In discussing the question, whether the fine cochineal would propagate without the care of man, the subdelegate of the province of Oaxaca, Ruiz de Nlontaya, (Gazeta de Literatura de Mexico,'1794, p. 228.) cites a very remark able fact in his memoir, " that at seven leagues distance from the village of Ncxapa, there is a place where, favoured by particular circumstances, the most beautiful grana fina is to be found. on very high and very prickly wild nopals, without any pains having ever been bestow ed in cleaning the plants, or in renewing the offspring of the cochineal." Besides, we are not to be astonished, that
t yen in a country where this animal is indigenous, it should seldom be found in a wild state, from the time that it began to be in request among the inhabitants, and to be reared in nopaleries. It is probable that the Toltees, before undertaking so troublesome a species of cultiva tion, collected the fine cochineal on the nopals, which grew spontaneously on the sides of the mountains of Oaxaca. Gathering the females before laying, the species would soon be destroyed ; and to obviate this progressive destruction, and prevent the mixture of the cotton and mealy cochineals on the same cactus, (the former depriving the latter of all nourishment,) nopa leries were established by the natives.
The plants on which the two species of cochineal are propagated, are essentially different ; and this undoubted fart is one of those which indicate a primitive difference between the grana pia, and the grana silvestre. is it probable if the mealy cochineal were lucre!y a variety of the cotton cochineal, that it would perish on the same cactus which nourishes the latter. and which botanists designate by the names of Cactus opuntia, Cactus tuna, and Cactus ficus liidica? NI. Thicry asserts, that in the plain of Cul-de-Sac in St Domingo, the cotton-cochineal does not live on the Cectu4 tuna, but on the Cactus per eskia, which he classes among the articulated Indian figs; and Ilumboldt believes that this naturalist has confound ed a variety of opuntia. with the true pereskia, which is a tre e with large and thick leaves, and on which he never vet found any cochineal. He considers it also as ex tremely doubtful, whether the plant called by Linnaeus Oictus coccinellVer, cultivated in Europe, is the nopal on which the Indians of Oaxaca rear the mealy cochineal. M. Decandolle, (Plantes grasses de Al. M. Bcdoute et Decandolle. livraison 24.) appears to be of Ilumboldt's opinion ; for he cites the wild nopal of Thiery de Menou ville, as synonymous with the cochineal Indian fig, ‘shich is entirely different from that of the plantations. Linnaeus indeed gave the name of Cactus ccccincllifer to the Indian fig, with which several botanical gardens of Europe had received the cotton cochineal, a species with a purple flower, (Ficus Indica vermiculos proferens of which grows wild in Jamaica, the island of Cuba, and it almost all the Spanish continental colonies. liumboldt shelved this cactus to well-informed persons, who had carefully examined the nopalcries of Oaxaca, and they uniformly told him, that the nopal of the plantations is essentially different from it, and that the latter is never to be found in a wild state. The Abbe Clavigero, also, who lived five years in Misteca, expressly says, that the fruit of the nopal on which the fine cochineal is reared, is small, insipid, and white, while the fruit of the Cactus coccinellifer is red. Ulloa maintains that the true nopal is without prickles ; but he appears to have confounded this plant with an Indian fig, which is found in the gar dens (conucos) of the Indians of Mexico and Peru, and which the creoles, on account of its gigantic size, the excellence of its fruits, and the beauty of its articulations, which are of a bluish green, and destitute of prickles, designate by the name of Tuna de Castilla. This nopal, the most elegant of all the opuntia, is in fact fit for the nourishment of the mealy cochineal, especially after its birth ; but it is seldom to be found in the nopale•ies o' Oaxaca.