96 INSECTS WHICH PREY UPON AGRICULTURAL PLANTS. 



latter with a row of yellow " spiracles " down the sides. The 

 best way of dealing with them is by hand-picking, or, if the 

 affected plants are small, by driving troops of clucks up and down 

 the drills. In Eussia hemp and cabbages are planted in alter- 

 nate rows, as the former is said to be obnoxious to these insects. 

 The small yellow cocoons sometimes seen attached to the cater- 

 pillar about to become a chrysalis should not be destroyed, as 

 they contain an ichneumon fly {Microgaster glomeratus), the larva 

 of which lives in and destroys the caterpillars. 



Trifhcena ^ronuhct (the Great Yellow Underwing Moth). — 

 This conspicuous insect is often seen in meadows during summer 

 in turning hay. The body and wings are a dull brown or ochreous 

 colour, and the under wings of a brigjht orang^e colour. The larva 

 is one of the " surface grubs '*' — the large dirty green species 

 which is often turned up in green-crop land. This feeds on roots 

 of various plants, especially turnips and other Crucifers, coming 

 up to the surface at night. In the larva-stage it exists through 

 the winter, becomes a large 'reddish chrysalis in April, and 

 emerges as a moth early in summer. Little damage is clone 

 by it. 



Mainestra hrassicce (the Cabbage Moth). — This is another of 

 the " surface grubs," and is allied to the last. It is abundant in 

 May and June, laying its eggs on the leaves of cabbages, and 

 the caterpillars which emerge are of a green colour, and feed at 

 night, lying concealed in the soil during the day. They can 

 accommodate themselves to almost any plant. The horns of the 

 imago are like fine threads ; the wings are deflexed when resting, 

 and are of a rich brown colour, the inferior ones a dirty brown. 



Agrotis exdamationis (the Heart and Dart JMoth). — So called 

 from the markings on its wings. It is of a clay colour, and 

 three-fourths of an inch long. The larva is also a surface grub, 

 and is of a dull lilac colour, living on the roots of various plants. 



Agrotis segetum (the Common Dart Moth). — Eesembles the 

 last very much, but is of a reddish-brown colour, ^though the 

 upper wings vary greatly, and are often of a clay colour ; the 

 feelers are "pectinated" or combed. The grubs are of a pale 

 livid colour, with dark lines down the back, and they feed on 

 nearly every kind of root. They are hatched in autumn, and 

 live throu^di the winter. 



Plusia ga77ima (the Y-Moth). — This moth, which flies 

 about by day regardless of the w^eather, lays its eggs on the 

 under side of turnip leaves and on other plants. These eggs 

 when magnified resemble the shell of an echinus, or sea-urchin. 

 The caterpillar is greenish, with six white lines down the back. 

 It spins a woolly white cocoon between the folds of a leaf, in 

 which it changes to a pitchy-coloured chrysalis, having a pro- 

 tuberance on the base of the abdomen, caused by the long 



