1058 



PRACTICE OF AGRICULTURE. 



Part III. 



tember or October it conceals itself, remaining torpid till February, when it re-appears. 

 In June it lays its eggs, in holes exposed to the full beams of the sun, by which they are 

 ^..c, matured. Tortoises attain most extraordinary 



longevity, and one was ascertained to have lived 

 in the gardens of Lambeth to the age of nearly 

 one hundred and twenty years. It will answer 

 .the purpose of a barometer, and uniformly in- 

 dicates the fall of rain before night, when it 

 takes its food with great rapidity, and walks 

 with a sort of mincing and elate step. It ap- 

 pears to dislike rain with extreme aversion, and 

 is discomfited and driven back only by a few 

 and scarcely perceivable drops. 



6820. The mud tortoise (T. lutaria, b), is 

 common both in Europe and Asia, and par- 

 ticularly in France, where it is much used 

 for food. It is seven inches long ; lays its eggs 

 on the ground, though an aquatic animal ; 

 walks quicker than the land tortoise; and is 

 often kept in gardens, to clear them from snails 

 and various wingless insects. In fish ponds it 

 is very destructive, biting the fishes, and, when 

 they are exhausted by the loss of blood, dragging them to the bottom and devouring 

 them. The tortoise may be fed on any vegetable refuse, .milk, worms, offal, or 

 almost any thing. Linnaeus says they are in all things extremely slow, and in 

 copulation frequently adhere together a month, and live several days after the liead 

 is cut oft". {Shaw's Zoology,) 



Chap. XL 



Of Insects and Worms which are or may be subjected to Culture. 



6821. The insects we mean to notice here are the silk moth, bee, and craw fish ; and 

 the worms, the leech and snail. 



6822. The silkworm or moth (Phalcena mori, 'L.,Jig. 56.) is a native of China, and was 

 introduced into Europe in the reign of the Emperor Justinian, A.D. 160. It is a 

 whitish moth, with a broad pale brown bar across each of the upper wings. The cater- 

 pillar or larva, emphatically known by the title of the silk worm, is, when full grown, 

 nearly three inches long, and of a yellowish grey color: on the upper part of the last 

 joint of the body is a horn- like process, as in many of the sphinges. It feeds, as every 

 one knows, on the leaves of the white mulberry, in defect of which may be substituted 

 the black mulberry, and even in some instances the lettuce, and a few other plants. 

 The silk worm remains in its larva state about six weeks, changing its skin four times 

 during that period, and, like other caterpillars, abstaining from food for some time 

 before each change. When full grown, the animal entirely ceases to feed, and begins 

 to form itself a loose envelopement of silken fibres in some convenient spot which it has 

 chosen for that purpose, and afterwards proceeds to enwrap itself in a much closer 

 covering, forming an oval yellow silken case or ball about the size of a pigeon's egg, in 

 which it changes to a chrysalis, and after lying thus enclosed for the space of about 

 fifteen days, gives birth to the moth. This, however, is always carefully prevented when 

 the animals are reared for the purposes of commerce ; the moth greatly injuring the silk 

 of the ball, by discharging a quantity of colored fluid before it leaves the cell ; the silk 

 balls are, therefore, exposed to such a degree of heat as to kill the inclosed chrysalides, 

 a few only being saVed for the breed of the following year. The moth, when hatched 

 is a very short-lived animal, breeding soon after its exclusion, and when the females have 

 laid their eggs, they, as well as the males, survive but a very short time. 



6823. The culture of silk varies but little in different countries ; it does not require 

 any great degree of skill, or a great capital ; and it is well known that the silk worm 

 with proper care, will breed and thrive very well in England. Though the price of 

 labor is too high in this country to render this a profitable branch of rural economy, yet 

 as it is carried on by some as matter of recreation, and may be useful in various ways, 

 we shall describe the process. 



6824. The culture and treatment of the mulberry is abundantly simple, and has been 

 given in noticing the silk culture of France and Italy. It is a mistake of various 



