404 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



spores lliat the ureilina; are termed rusts. 

 Generally tlie iiiyfeliiim of the uredinK is 

 localized and only occupies a liniiteil point 

 of the tissue of the nurse ])lant. It does 

 not traverse it throujjhout to fructify in a 

 determined point like tlie niyti'liiiin of Inint 

 and the greater number of Ustllmjit. Where 

 the germinative tulie of a spore enters the 

 tissue of a jilant, it ramifies and produces its 

 fructiticatioiis. The leaves cliargetl with 

 rust sjjots are soon exhausted, they turn 

 yellow and die prematurely. The evolution 

 of, rust varies much, a description of the im- 

 portant rusts seems therefore desirable. 



Sapehda carcharias (shagreen saperda). 

 ■ — Among the longicorn coleoptera injurious 

 to wood, the saperda is one of the most 

 common. It is 27 millimetres in length, 

 brownish-yellow colour ; the elytra carry 

 black projecting points which impart to 

 them a shagreen appearance. The larva of 

 the saperda is one of the most dangerous to 

 young poplar plantations. The eggs are 

 arranged in fissures of the bark, the larvae 

 perforate these and Vjore ascending holes in 

 the wood. The metamorphosis lasts two 

 years and nymphosis occurs near the exit 

 hole. The trunks of certain poplars, less 

 than twenty years old, are sometimes riddled 

 with holes to such a pitch, that a slight 

 gale suffices to cause them to fall. 



Saperda populnea (saperda of the pop- 

 lar). — This saperda is only 10-12 millimetres 

 in length ; it is blackiah-brown ; the elytra 

 are spotted with small yellow dots. The 

 female lays its eggs in the branches of the 

 poplar. The larva penetrates into the 

 branch, and there bores a long hole. Its pre- 

 sence is indicated by a circular swelling of the 

 bark. The branches attacked show swellings, 

 termeil galls. The larval life last two years. 



ScOLYTES. — The scolytes are small-sized 

 coleoptera, which the number ami nature of 

 their depredations render very injurious to 

 forest and fruit trees. They bore holes of 

 various shapes, for the most part between 

 the bark and the wood, in wliich the female 

 lays its eggs. The larvse bore secondary 

 holes, which sometimes penetrate directly 

 and deeply into tlie wood. They pn-tVrably 

 attack sickly trees, because the circulation of 

 the sap is not so intense as to hinder their 

 mining work. Their presence is indicated 

 by the leaves yellowing without a fixed 

 reason. The scolytes greatly resemble the 

 hylesines ; they present the peculiar char- 

 acter of having an ovoid head, covered with 

 a tuft of hair, the antennae, terminated by a 

 highly developed swelling, and tlie abdomen 

 truncated at its upper and posterior part. 



SCOLYTUS OF THE PLDM. Sfdiytii.s I'riini. 

 — It ravages plums ami apple-trees. The 

 larvse bore their holes in the liber and there 

 pass the winter in tht^ nymph state. The 

 Bsects hatch in Aj)ril an<i lay their eggs in 

 May. The foliage of the invaded trees is 

 scanty, their growth is sickly, and they do 

 not yield fruits. 



ScOLYTDs (Rugose). Eccoptognster regu- 

 osus. — It preferably attacks small branches 



and limbs. The perforated parts of the tree 

 turn yellow and die. Plum-trees are especi- 

 ally chosen liy it. 



Septouia.— These are parasitic fungi of 

 the leaves. They proiiuce withered and dis- 

 coloured spots on which there are formed, 

 below the epidermis, picnydes, which have 

 pierced through the mouth of a liole through 

 which the spores escape. There are more 

 than 500 species of Sfpturin, but the small 

 s])ots which they produce on the leaves are, 

 in general, without serious conse(|uence. 



SePTOUIA TRITICI, SKI'TOHIA (iRAMINOM. 



—In tlie spring the leaves of autumn wheat 

 are covered with spots ; this fungus exhausts 

 the leaves which wither and die prematurely. 



Sbsi.'E. — Butterfiies, which have a portion 

 of the wings transparent, which causes them 

 to resemble wasps and flies. Their cater- 

 pillars are miners and live in the trunks of 

 trees where they produce the same depre- 

 dations as the caterpillars of the Cossus and 

 the larvffi of the Saperd;v. 



Sesia apiformis. Trorhilium api/ormi. 

 — 'Butterfly resemliling a wasp. It shows 

 itself in June. The female lays its eggs at 

 the base of white-wood trees (poplar, birch, 

 willow, aspen). The caterpillars bore holes, 

 which may traverse the tree from one part 

 to another, and even reach the roots. The 

 metamorphosis lasts two years. 



Sksia myopiformis. — The caterpillar 

 lives in the interior of the trunk of the 

 pear-tree and the apple-tree. 



SiLPHs.— Silphs preferably attack de- 

 composing animal matter ; but certain species 

 form an exception and attack cultivated 

 plants. 



SlLPHAOPACA(beetcarrion beetle). SiLPHA 

 atrata (black sylph). — Coleopterse, 1 centi- 

 metre long, entirely blackish-brown, the 

 corselet is highly developed, and in the form 

 of a shield. The larva attains 1^ centimetres 

 in length ; it is black and resembles a large 

 wood louse. These insects cause serious 

 damage to beet field.s. Their invasion of 

 Frame dates from 1846. They have spread 

 in such numbers as to lay waste the depart- 

 ments in the North of France. The larva 

 of great voracity attacks beet le;ives ; it hides 

 all day in the soil, and only issues forth at 

 night "to commit its depredations. It appears 

 in May to nymphose in the soil in June. 



SPHiKRl.\CEiE. — The s}ihariare<€ comprise 

 a great number of saprophytic fungi, or 

 parasites ; they have small, iihuk, and not 

 very visible peritheca. These fungi often 

 cause serious damage to cultivate! I plants. 



Sph^rella fragari^ (spots of the 

 leaves of the strawberry). — The leaves at- 

 tacked by this fungus are covered with 

 purple-brown rounded spots, separate or 

 contiguous, which appear on their upper 

 face. They increase rapidly in size, wither 

 in the middle, and are finally ])ierced right 

 through. On these spots all the conidia are 

 formed, which readily germinate on the 

 strawberry leaves. When it bleeds with 

 intensity it may stop the growth of the 

 fruit and kill the plant. 



