SOWING. 



SPAN-WORMS. 



SOWING. See SEED. 



SOWING MACHINE. See DRILL. 



SOW-THISTLE (Sonchus, from somphus, hol- 

 low ; the stems being hollow). A rather large 

 genus of annual or perennial plants, rarely 

 shrubby, generally tall. They have hollow 

 sterns, and more or less pinnatifid or lyrate 

 leaves, toothed or prickly at their edges. The 

 surface of the herbage is usually smooth, that 

 of the inflorescence hairy or glandular, often 

 viscid. They contain a bitter white juice, and 

 are plants of easy culture in any common soil. 

 The herbaceous species are increased by divi- 

 sion ; the seeds of the annual and biennial 

 kinds only require to be sown in the open 

 ground. There are in England three indige- 

 nous perennial species : the blue sow-thistle 

 (S. coeruleus), the tall marsh sow-thistle (S. pa- 

 lustris), one of the largest herbaceous plants, 

 growing from 6 to 8 feet high; and the corn 

 sow-thistle (X. /iv,,>/.s). The most- common 

 native species is annual in habit, viz., the com- 

 mon sow-thistle (S. oleraceus), which is found 

 almost everywhere, in cultivated and waste 

 ground; flowering from July to September. 

 Hares and rabbits are very fond of the herb- 

 age, which, like the root, is milky and bitter. 

 The leaves are sometimes dressed and eaten 

 among other culinary herbs, and the roots have 

 occasionally been converted into bread. 



SPADE HUSBANDRY. There are many 

 situations in which, from the small size of the 

 enclosures, or the want of sufficient power for 

 the easy working of the common or the subsoil 

 plough, the cultivator may prefer the employ- 

 ment of manual labour with the spade ; and it 

 is fortunately found by experience that the 

 difference in the expense of deep-digging, or 

 spade husbandry, is not materially different 

 from that of the subsoil plough. A great mass 

 of information on this head was collected by 

 the late Dr. Yelloly ; not, however, so much 

 with thfi view of showing the increased fer- 

 tility of the soil by deep-stirring, as with the 

 intention of demonstrating the immense field 

 which is thus opened for the profitable labour 

 of a teeming and increasing population. (See 

 Dr. Yelloly on 'Spade Husbandry ; also British 

 Fanner's Mog**MC) 



The trials which have been hitherto made 

 of spade husbandry, in various parts of the 

 kingdom, have been insufficient, in point of 

 extent, to afford any adequate criterion of the 

 general applicability of that practice. Such 

 trials, indeed, have been usually regarded either 

 as matters of speculation and experiment, or 

 as charitable efforts adopted by the benevolent 

 to givje employment to the poor, without refer- 

 ence to pecuniary expediency. 



In most parts of Biscay and the north of 

 Spain, the fields are commonly cultivated .by 

 the spade : great crops of potatoes and turnips 

 are raised by these means." (Sinclair, p. 394; 

 Brii. Husbandry, vol. ii. p. 571.) See FLANDERS, 



HUSK AS DRY OF. 



SPANISH NEEDLE (Bidens). See BUR- 

 MARIGOLP. 



SPAN-WORMS. A common appellation 

 applied to those caterpillars called also loopers, i 

 and geometers. In New England they are 

 called canker-worms 



The caterpillars of the Geometrsc of Lin 

 noeus, earth-measurers, as the term implies, or 

 geometers, span-worms, and loopers, have re- 

 ceived these several names from their peculiar 

 manner of moving, in which they seem to 

 measure or span over the ground, step by step, 

 as they proceed. Most of these caterpillars 

 have only 10 legs ; namely, 6, which are jointed 

 and tapering, under the fore-part of the body, 

 and 4 fleshy proplegs at the hinder extremity; 

 the 3 intermediate pairs of proplegs being want- 

 ing. Consequently, in creeping, they arch up 

 *he back while they bring forward the hinder 

 part of the body, and then, resting on their hind- 

 ! legs, stretch out to their full length, in a straight 

 j line, before taking another step with their hind- 

 legs. They have the power of letting them- 

 selves down from any height, by means of a 

 silken thread, which they spin from their 

 mouths while falling. Whenever they are 

 disturbed they make use of this faculty, drop 

 suddenly, and hang suspended, till the danger 

 is past, after which they climb up again by the 

 same thread. These span-worms are naked, 

 or only thinly covered with very short down ; 

 they are mostly smooth, but sometimes have 

 warts or irregular projections on their backs. 

 They change their colour usually as they grow 

 older, are sometimes striped, and sometimes of 

 one uniform colour, nearly resembling the bark 

 of the plants on which they are found. When 

 not eating, many of them rest on the two hind- 

 most pairs of legs against the side of a branch, 

 with the body extended from the branch, so that 

 they might be mistaken for the twig of the tree ; 

 and in this position they will often remain for 

 hours together. When about to transform, 

 most of these insects descend from the plants 

 on which they live, and either bury themselves 

 in the ground, or conceal themselves on the 

 surface under a slight covering of leaves fas- 

 tened together with silken threads. Some make 

 more regular cocoons, which, however, are 

 very thin, and generally more or less covered 

 on the outside with leaves. A very few of the 

 span-worms fasten themselves to the stems of 

 plants, and are changed to chrysalids, which 

 hang suspended, without the protection of any 

 outer covering. 



In their perfected state these insects are 

 mostly slender-bodied moths, with tapering 

 antennae, which are often feathered in the 

 males. Some of the females are without 

 wings, and are distinguished also by the oval 

 and robust form of their bodies. These moths 

 are most active in the night ; but some of them 

 may be seen flying in thickets during the day- 

 time. They are very short-lived, and die soon 

 after their eggs are laid. 



It was formerly supposed that the canker- 

 worm moths came out of the ground only in 

 the spring. It is now known that many of 

 them rise in the autumn, and in the early part 

 of the winter. In mild and open winters I have 

 seen them, says Dr. Harris, in every month 

 from October to March. They begin to make 

 their appearance after the first hard frosts in 

 the autumn, usually towards the end of Octo- 

 ber, and they continue to come forth, in greater 

 or smaller numbers, according to the mildness 

 or severity of the weather after the frosts hav 



1005 



