294 MANUAL OF ELEMENTARY ZOOLOGY 



parts, three pairs of true legs, four, or fewer, pairs of soft 

 " prolegs," and a pair of " claspers " at the hind end of the 

 body. They possess silk glands, which open on a spinneret 

 situated below the mouth. The butterfly and moth which 

 are figured as examples in this chapter are both of interest 

 as being harmful to crops. The dull-coloured larvae of the 

 Heart-and-Dart Moth live under the soil by day and come 



FIG. 202. — The Green-veined White Butterfly (Pieris napi), and the 

 ichneumon fly that preys upon it (Hemileles melanarius). — 

 From Theobald. 



i, Imago ; 2, egg ; 3, caterpillar ; 4, chrysalis or pupa ; 5, the ichneumon fly ; 

 6, natural size of the latter. 



out at night to feed, doing much damage to a variety of 

 plants in gardens and in fields. The best remedy against 

 them is a dressing of soot and lime. The Green-veined 

 White Butterfly lays its eggs upon cabbages and other 

 Cruciferse, to which the larvae do injury, though they are 

 responsible for less damage than the Large and Small 

 Whites (P. brassiccz and P. rupee), whose habits are similar. 

 Hand picking is practically the only remedy. 



