NOTES ON TKIFURCULA IMMUNDELLA, ZELLEK. 119 



length of the larva is almost exactly Imixi. When about to change, the 

 larva thrusts its old head into the side of the mine, soon commences 

 feeding afresh, and as it progresses it gradually leaves its old skin 

 behind. The larva in its second instar does not differ greatly from 

 that in the first instar. It is rather stouter in proportion, but the 

 relative width of the well-marked segments is much the same. The 

 head measures 0"15mm., the length of the larva is about l-6mm. The 

 mine in the first two stadia is very flat and the frass is gathered into 

 the centre, leaving a narrow pale border on each side. It thus forms 

 a narrow black or very dark green track, which, when old, appears as 

 a black stain in the bark. The mine often runs straight down beside 

 one of the ridges of the twig, sometimes passing through the ridge and 

 continuing on the other side. More often, however, I think, the larva 

 after mining down from 5mm. to 10mm., turns and mines up the stem 

 for a short distance and then down again. When minmg upwards it 

 sometimes crosses its earlier mine, thus forming a short loop. When 

 the larva has mined in this way to a length of from 16mm. to 20mm. 

 it again lays up for a change of skin. Soon after the change the larva, 

 now in its third instar, leaves the ridge of the stem and commences 

 mining down the centre of one of the furrows. The cuticle of the bark 

 is now slightly raised and assumes a brownish hue. The larva appears 

 pale greenish in the mine and may be seen feeding in a Nepticulid 

 manner. It still leaves a broad, irregular central line of black frass, 

 which appears of a dusky tint when seen through the bark. It is not 

 easy to see what the larva is doing under the bark as it is of no use to 

 hold the broom twig up to the light, a plan that succeeds well enough 

 with a leaf-miner. As in most of the lower leaf-miners, the larva in 

 its third instar shows a considerable development. The width of the 

 head is about 0'23mm., and length of the larva about 3mm. The 

 colour of the head hnes is brown and that of the body bright orange- 

 ochreous. The prothorax is still yery wide, and both the meso- and 

 metathorax are much swollen above and carry each a pair of swellings 

 or foot-pads beneath which are much spiculated. If my observation 

 was correct then the large spiracle on the eighth abdominal segment 

 is placed low down towards the venter, and as the larva mines lying 

 on its back this position of the spiracle may be useful. On each side 

 of the tenth abdominal segment there are two long spines, an upper 

 and a lower. Progression is probably performed by means of the 

 swellings on the thoracic segments and these strong lateral spines of 

 the last segment. The larva continues its mine down the centre of the 

 furrow until the whole mine reaches a length of about 33mm. It then 

 lies up for what is probably the last change of skin. In the fourth 

 instar the larva is very stout and the segmental divisions well marked. 

 The head is small, flat, and grey, with the usual lines nearly black. 

 The whole body is bright orange-ochreous. The dorsal aspect shows 

 the prothorax to be very much wider than the small head, which is 

 capable of being almost entirely withdrawn into it. From the prothorax 

 to the first abdominal segment the larva increases much in width. The 

 second abdominal is rather narrower, and the following segments are 

 much of the same width, but the ninth abdominal is much narrower 

 than the eighth, while' the tenth is very narrow. In the lateral aspect 

 the outline of the larva slopes evenly upwards from the head to the 

 metathorax, then runs level along the back to the eighth abdominal, 



