the Life History of TricJioptilus imludnm. 147 



under sides of the leaves, on tlie petioles and on the dead flower- 

 stalks of tlie previous year, and even on the peat beside the plant. 

 It is briglit yellow at first, becoming afterwards duller in tint. It is 

 oval in any longitudinal section, circular in any transverse one. Its 

 length is 0"38 mm. and its diameter 0-24 mm. 



It has very large bold sculpturing consisting of a net-work of 

 ribs enclosing irregular polygons. The ribs are broad, about one- 

 third of the widtli of the enclosed hexagons (or as may be). Tiie 

 diameter of the cells is about 0*02 mm., of a cell and one wall about 

 0-026 mm. 



Newly-hatched Larva. 



The newly-hatched larva is fully 1 mm. in length when stretched 

 out. Head, prothorax, and anal plate dark, but not black, hairs and 

 bases dark, tlie rest white or colourless. Tubercles I and II are 

 distinct from each other but very close togetlier, I very small, hair 

 about one-sixth the length of that of II which is about 0'06 mm. long, 

 both incline backwards. The corresponding hairs on 2nd and 3rd 

 thoracic and 9tli and 10th abdominal segments are no less than 0'20, 

 0'23, 040, and 0"20 mm. long respectively, that on 9tli abdominal 

 segment being in fact as long as half tlie length of the larva, when it 

 is not extended. Ill is about 0"17 mm. long and is directed forwards. 

 IV and V are on distinct bases but very close together, rather more 

 on a level than usual (the contrary, for example, of Amb. acantho- 

 dactijla), front hair 0'06 mm., posterior 0'18 mm, long. A long way 

 below, about middle of segment, are two hairs, one about 017 mm. 

 long and the other below and in front of it about O'l mm. VI 

 appears to be absent and these are two of the three hairs of VII. 

 On the prothoracic plate one of the three usual front liairs seems to be 

 absent, and only the long central one of back row is clearly seen. 

 Of the usual four pairs of hairs on meso- and meta-thorax, the third 

 appears to be represented by one hair only. 



The props of prolegs are about 0'04 mm. long, with three crotchets, 

 four on claspers. 



The larva appears to have 4 instars. In the first it is 

 without tubercle VI, and without skin points. In the 

 second instar it acquires these, and I and II acquire a 

 common chitinous base. Tliere are no secondary hairs. 

 At this stage it hibernates in the autumnal brood. 



In the third instar it acquires a small number of 

 secondary tubercular hairs, making the tubercles into 

 warts. 



In the fourth instar it differs from the third in the 



