46 THE REPORT OF THE No. 33 



quickly when exposed to the air, adding gloss to the shell. When the egg is laid 

 on the outside of the plant the shade intensifies to a clear light yellow in about 

 two hours, showing evenly over the whole egg, continuing so for from one to three 

 days when a faint tinge of green appears. This gradually deepens until from 

 the second to the sixth day the ends darken slightly giving a general appearance 

 of pale olive green. Usually the next day (although sometimes simultaneously) 

 the shell begins to show slight sculpturing, becoming complete in a day or two. 

 All gloss then leaves the egg, and it becomes quite dull, and slightly darker. 

 The pattern of the sculpturing is more evident on eggs laid on the outside of the 

 plant, and is of a very even hexagonal form. No particular change is seen after 

 this until the head of the embryo begins to show. Usually this takes place in 

 from three to five days after sculpturing, depending very much on the weather. 

 Even in early fall it may last fourteen days. At first the head shows faintly as 

 a dark mark, then soon darkening to a plainly visible circular black spot. In 

 most cases this is about one-third distant from either end, but may be anywhere 

 along the egg, as the larva moves about before hatching. With eggs laid inside 

 the petiole, coloration is less marked. Just before hatching, the egg is a very 

 pale green colour, the head of the larva within showing plainer than in eggs 

 exposed to the air. The egg enlarges considerably before hatching, becoming 

 slightly distorted in outline. 



The Larva. The newly-hatched larvae remain for a short time near the 

 egg mass, but soon ascend the stem, to begin feeding on the leaflets. Being 

 legless, a large number fall to the ground. In the insectary most of these perished 

 unless they were assisted back on to the leaf. In the field this fact doubtless 

 results in considerable larval mortality, especially if hatching occurs during a 

 rain or heavy wind. The first instar larvae do not retire to the base of the plant 

 in the daytime, but remain on the underside of the leaf near where they were 

 feeding, curled tightly, the last segment just covering the head. An epidermal 

 hair or two of the leaf is usually embraced to help anchor the larva. In the field 

 many of the young larvae feed within the unopened leaflets at the base of the 

 plants, thus obtaining ample cover during the day without leaving their feeding- 

 ground. The propensity of the young larvae to remain in the one location until 

 some growth is made can be observed very noticeably under insectary conditions. 

 With two hundred specimens observed in vials not a single one voluntarily left 

 a dried, withered leaf for a fresh one without being transferred to it bodily. 

 Before the first moult the feeding is confined to the centre of the leaves, the 

 injury showing as small round holes. After the larva has attained the third and 

 fourth instar it feeds from the leaf margin as well. They feed at night only, 

 dropping to the ground to spend the day curled up under the refuse at the base 

 of the plant. 



With careful searching some larvae may be found in the field any time from 

 the second week of September until the third week of June of the following year. 

 They are not difficult to identify, and are not likely to be confused with other 

 insects in the clover field. The green larva with its pale dorsal stripe and its 

 habit of curling up when not feeding is easily distinguished. Although the 

 colour is usually green it may be cream, bluish, or with a tinge of pink. The 

 percentage of cream-coloured larvae was 2.6 per cent., and they produced normal- 

 coloured adults. 



Three moults were observed, the length of instars being very variable on 

 account of the intermittent feeding of the larvae, due largely to adverse weather 

 conditions. The first instar (fall observation) averaged 17 days, the second 



