38(J INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



iiutiiiuu the hist generation of these phmt 

 lice no longer produce viviparous iu<livi(liials 

 the same as themselves. Tliey then lay 

 eggs from which i.ssue a short time after- 

 wards either males or winged females which 

 copulate. These females lay eggs in their 

 turn. Amongst these esrgs some give liirth 

 to apterous viviparous friiialcs which wait, 

 hidden in the moss (jf the inink, the heat 

 of the spring to repro.luri' tlimiselves and 

 so recomnienee the cycle described. The 

 others hibernate, hidden in the fissures of 

 the bark and are not hatched until spring. 

 Plant lice have not therefore like otlier in- 

 sects slow and complicated metamorphoses 

 which limit tlie number of annual generations, 

 but although compelled to go through a 

 special cycle the females are capable of 

 reproducing themselves indefinitely into 

 similar individuals without aid of the male 

 and without slow evolution. That enables 

 them to create in a season a legion of in- 

 dividuals endowed with the same destructive 

 capacity and the sum of the work of which 

 often produces terrible effects on the plant 

 invaded. The number of species is unlimited, 

 and there is no plant which does not possess 

 one or more species which produce a cliai - 

 acteristic degeneration of the organs attackci 1. 

 The spitting Aphrophora. A2)hri>j)liuni 

 Spumaria. Hemiptera, of the grasshopper 

 family, which lays its eggs in the end of 

 autumn in the liark of jjlants. The larvae, 

 which hatch in tlie spring, suck the juice of 

 plants and surround themselves so as to pro- 

 tect themselves with a viscous matter con- 

 .■sisting of air-liells, resembling saliva so much 

 as to lie mistaken for it. Where they occur 

 in very great numbers they may become in- 

 jurious. 



Armillaria Mellea (tree-root rot). — This 

 fungus lives as a saprophyte and as a parasite ; 

 its mycelium penetrates into the living roots 

 of very different species of trees and develops 

 in the bark and in the exterior layers of 

 wood ; from thr r i its it gains the foot of the 

 tree and then- it inoilurrs yellowish-brown 

 ■clusters of riMrptajlr^ (in the level of the 

 ground. It attacks vines, apple-trees, niul- 

 ijerry-trees, fig-trees, on which it causes 

 <liseases which are confused with others 

 under the general name of rot. [Coinmon- 

 ■est and most widely distril)uted of British 

 toad-stools.] 



A'PHALIA SPINARUM (tumip saw-fly), see 

 Tenth REDO. 



Athous. — Blaterides, the larvae of which 

 injure crops, see Aghiotes. 



Athous h.emourhoidaus, injurious to 

 the growth of flowers. 



Athous hirtds, injurious to beets. 



Athods NIGER, the black click beetle, in- 

 jurious to potatoes. 



Atomaria LINEARIS. — Coleoptera, 1 milli- 

 metre in length, with finely dotted elytra. 

 The perfect insect appears at the moment of 

 the germination of beet seed. It attacks the 

 subterraneaii portion of the seedling and de- 

 rstroys it. If the plant is in braird the in- 

 .'iBct pierces small holes near the collar ; the 



young lieet bl.ackens and dies. If it survives 

 the root becomes forked and its sugar content 

 is lowered. The insect afterwards attacks 

 the leaves. The damage is done from May 

 to July. 



Black Rot of the Grape. O'uif/iuirdia 

 B ill ici'lli.— This disease, reported iii France 

 for the first time in 1885, is of American 

 importation. It causes frightful ravages 

 because it invades and destroys the grapes. 

 It is due to the parasitism of a Sphoeriaceje 

 which in succession shows conii/ia fruit and 

 nsci fruit. On the stalks of the leaves 

 black rot shows itself l)y reddish, more or 

 less circular, well-defined spots. These spots, 

 small at first, liecome larger and finally run 

 into large black sjints consisting of conidia 

 fruits. Tliisc s;iiiir sp.its'are formed on the 

 branches mi tlif i luster of grapes and on the 

 grapes thfiusilvrs. 'i'lie black rot appears 

 about mid-July when the grapes are as big 

 as peas ; it first forms a livid spot which en- 

 larges quickly and invades the whole pulp ; 

 the grape then fades, its surface is depressed, 

 forming large folds and it dries rapidly, as- 

 suming a violet-black colour. During this 

 tiiiif there is formed on the black wrinkled 

 MiiliKc iif the grape thousands of small black 

 uliiliiilar projecting gi'anulations which are 

 tlie conidia fruits of tlie fungus called 

 pycnides. It is not until winter tliat the 

 peritheca, globular couceptacles tilled with 

 usci, are formed in the midst of the tissues 

 of the dried grape. Up to the month of 

 June of the following year these peritheca 

 are found filled with well-developed asci 

 on the grapes which have passed the winter 

 either on the stock or on the soil. The 

 ascospores germinate in a few hours after 

 having been projected out of the asci. 

 They put forth a germination tube which 

 penetrates the epidermis of the leaves and 

 there produce the spots described above. 

 The organs of reproduction of black rot are 

 of tliree kinds : the first and the second are 

 coiiiili:i fruits whicli ;ip]ic,ir in summer on 

 the Icucs .Hid the truits .uid '..'ive out sporeS 

 whicli s|ii-c;id the dise.iM- .liirnig file year; 

 the thin! cniisisls .,1 iieritl.era, the spores of 

 which transmit the diseasr Im vines ||-miii one 



year toaiiofller. A klinwle,|-e ,,1 tlie sueees- 



sive phases of this ilisease alone enables it to 

 be overcome effectively. 



BoMBYCiDES. — Nocturnal moths, heavy 

 and squat in shape, with a body abun(l- 

 antly covered with hair ; the wings are at 

 rest, sloped like a roof. The males have 

 three pectinated antennae; they are smaller 

 and darker in colour than the females. The 

 caterpillars almost always bristle with numer- 

 ous long hairs ; they spin cocoons to trans- 

 form themselves into chrysalides. 



Bo.Miivx ANTiQiJA, Orgya antiqua (the 

 common vapourer or brown tussock). — 

 Sexual dimorphism ; female grey, apterous; 

 male reddish-brown, two white spots on the 

 U])per wings ; the butterfly appears in June. 

 Tile caterpillars are especially fond of pear- 

 trees. Several generations up to October. 



BoMBYX Chrysorrhea Moth. Liparis 



