ESCULENT- ROOTED PLANTS. — THE TURNIP. 



197 



those enemies known as surface-grubs, and often 

 attack the turnip-bulb, particularly in gardens 

 where the plants are nearly full grown. These 

 have also their natural enemies in the genus Cryp- 

 tops — Scolopendra of 

 Fig- 76. some (the centipedes), 



fig. 76. If the value of 

 these were rightly 

 understood, the vul- 

 gar prejudice against 

 them would be re- 

 moved. They are all 

 of the carnivorous or 

 garden centipede. flesh-eating section, 

 and devour immense 

 numbers of underground grubs, larvae, &c. They 

 live entirely on the insects they find in the soil ; 

 they are of a rusty-red colour, more than an inch 

 in length ;antenna3hairy,having seventeen joints: 

 legs hairy, having twenty-one on each side. One 

 species, Cryptops hortensis, is almost entirely 

 confined to the southern counties of England ; 

 the rest are common everywhere. 



Amongst lepidopterous insects — that is, those 

 of the butterfly and moth kind — there are some 

 species injurious to turnip crops, which are thus 

 described by Mr Stephens in " The Book of the 

 Farm," vol. ii. p. 79 :— 



" Cerostoma xylostella (the turnip diamond- 

 back moth), fig. 77. — When at rest, the wings are 



Fig. 77. 



TURNIP DIAMOND -BACK MOTH. 



closed and deflexed, and the horns are projected 

 forward in a straight line. It is more or less 

 brown. The upper wings are long and narrow, 

 and, when closed, form two or three diamonds 

 upon the back. The inferior wings are lance- 

 shaped, and of an ash colour, with a very long 

 fringe. Its length is 2\ lines. The caterpillar 

 is green, about half an inch in length, slender, 

 and tapering to both ends. They are exceed- 

 ingly active, and on the slightest touch wriggle 

 themselves off the leaf they are feeding on, and 

 let themselves down by a silken thread, and re- 

 main suspended till the cause of alarm subsides. 

 As many as 240 have been counted on one leaf; 

 and such is their avidity, that not the smallest 

 vestige of a green leaf is left by them. This 

 larvae is destroyed by a black ichneumon, named 

 Campoplex paniscus." 



Mamestra brassicce (cabbage-moth), fig. 41, at- 

 tacks the Swedish turnip. 



Mamestra oleracea (white-line brown-eyed 

 moth), fig. 78 (see section Cabbage), is also an 

 enemy to the turnip and lettuce, as well as the 

 cabbage. This moth is of a dark rusty-brown 

 VOL. II. 



colour. " The antenna) have white scales ; the 

 abdomen is ash grey, with brown tufts ; the 

 Fig. 78. 



white-line brown-eyed moth. Natural size. 



feet are greyish brown, yellow-ringed below ; 

 the fore wings have no connected cross lines ; 

 the round middle spot is surrounded with 

 white; the kidney spot is orange colour in the 

 shape of a lunule ; very delicate white and black 

 dots are seen on the watered band ; the fringes 

 are deeply toothed, bordered by a faint white 

 line ; the under wings are ochre yellow, or dirty 

 white, with darker shades towards the whitish 

 fringes. The reddish or yellowish brown cater- 

 pillar has on the back, and on each side, a dark 

 stripe, and a whitish one nearly over the feet ; 

 the under side and feet are light brown ; it is 

 dotted with black between the dark stripes. 

 When young, and sometimes also when fully 

 grown, the ground colour is green. The pupa 

 is shining reddish brown, and remains in the 

 earth during winter." — Kollar. It feeds upon 

 the cabbage, turnip, and lettuce, and is best 

 destroyed by sprinkling caustic lime over the 

 plants as soon as the caterpillar appears, repeat- 

 ing the operation while they continue to appear. 



Pontia brassicce, fig. 44 ; Pontia rapce, fig. 46 ; 

 and Chrysomela betulce, are all more or less inju- 

 rious to turnip crops, feeding on the leaves. 

 They are, however, kept in check by the ichneu- 

 mons Microgaster glomeratus and Pimpla instiga- 

 tor, and by the cynips Pteromatus brassico? and 

 P. pontia. 



Anthomyia gnava, in its maggot state, attacks 

 turnips during autumn, forming cavities in the 

 bulbs. The female fly is ash-coloured, with a 

 black line down the body, broadest at the 

 base, and is nearly \ of an inch in length, and \ 

 an inch in expanse. The male fly has a black 

 trunk and legs ; body linear, of the same colour 

 as the female, with testaceous bands and black 

 dorsal spots. 



Anthomyia brassicat (cabbage-fly), fheA.radi- 

 cum of some entomologists, fig. 79. When the 

 maggots attack the roots of the cabbage, the 

 roots " become enlarged and carious, the mag- 

 gots revelling in the cavities. They are very 

 similar to those of flesh-flies, being fat, yellowish 

 white, tapering to the head, which has two black 

 hooks. The blunt tail has two brown spiracles 

 and some minute spines. Excepting in the 

 depth of winter, they may be found feeding all 

 the year. Heat, however, generates them most 

 rapidly, for in May and June they exist at the 

 same time as maggots, pupae, and flies. The 

 larvae are transformed to bright rust-coloured 

 horny pupae in the roots, or they bury themselves 

 in the earth. These cases have a few tubercles 



2c 



