CONTRIBUTION TO THE LIFE-HISTOKY OF C(ENOBIA RUFA. 109 



every stem within reach. At last, when we were nearly giving it up, 

 I happened to pull a sickly-looking one, which come up quite easily, 

 and, on examining the lower end, we saw at once something was 

 feeding within. On cutting it open, we found a small, pinky-white 

 larva of the Nonagriid type, and felt sure we had got the right thing. 

 We set to work hard after this, going for all the unhealthy-looking 

 stems, and managed to get about a dozen, some of which duly produced 

 imagines. Since then several facts have been accumulated, of which 

 the following appear to be among the most interesting. 



Ovum : The ovum is about -|mm. in diameter, round, whitish, and 

 quite devoid of markings, becoming darker before hatching, when the 

 pinkish segments of the young larva can be seen through the shell. 

 The eggs are laid in the centre of old rush stems, and the Avay they are 

 placed there is most interesting. The ? possesses two sharp spines on 

 the last segment (see pi. x), with which she makes a longitudinal slit in 

 the stem ; the spines are then forced apart, whilst the ovipositor is thrust 

 betw'een them into the pith, and the eggs are deposited in bunches of 

 three to eight. The ovipositor and spines are then withdrawn, and 

 the cut closes, and is hardly to be seen without a lens. The eggs 

 Avere laid from July 20th to August 1st, and began to hatch about 

 August 10th. 



Larva : When first hatched, about 3^mm. long ; shining creamy- 

 white ; head, thoracic plate, and anal-plate, blackish-brown ; meso- 

 and metathoracic segments rather flattened, and pinky-white in colour, 

 other segments rather raised and pinky-brown, giving the larva a rather 

 banded appearance, the body having a few hairs arising from tubercles; 

 true legs slightly dark at tip ; ventral surface and legs whitish. The 

 fullfed larva examined on June 3rd, 1908, measured about 16mm. 

 long ; head yellow-brown ; prothorax and anal segments with straw- 

 coloured, shining plate ; colour of body pinkish-white, ventral surface 

 dirty-white ; head and body emitting some small whitish bristles ; 

 segments bearing also thirteen to fourteen small blackish tubercles. 

 The thoracic segments are rather flattened, rest sw^ollen, anal segment 

 flattened, true legs yellowish, prolegs dirty-white, dorsal line whitish. 



Habits of larva : The young larviB remain in the old stems, 

 making galleries in the pith towards the root, and keep more or less 

 together. They appear to hybernate in these old stums, and early in 

 the spring bite their way out, Avhen each one enters a growing stem. 

 The larva? appear to feed in several stems. They bite an oval-shaped 

 hole about a quarter of the way up the stem, and, entering, feed head 

 downwards, ejecting frass through the hole; on reaching the root they 

 eat their way out, and enter another stem. The infested stems 

 quickly turn j'ello wish-green and wither. The ejected frass can be 

 seen on the moss, etc., round the tufts of rushes, and a little searching 

 reveals the infested stem. When about to pupate the larva enters an 

 old stem low down just where the sheath ends, beneath the mossy 

 surface of the fen, eats out a chamber, leaving a thin skin over its 

 emergence hole, which is just on the fen surface, and pupates head 

 upwards. They are fullfed from the end of May to the middle of 

 June. The foodplant is Jimciis laniprocarinis. Mr. Bankes believes it 

 feeds in J uncus ejf'usus in his district, and it may feed in some of the 

 other Juncus species also. 



Pupa : ll^mm. long, with a distinct " beak; " anal end of pupa 



