on colour-relation. 223 



July 20th. — I drew the lightest larva (figured at 

 PL XL, fig. 5), which was of a very light delicate shade 

 of brown, and had scarcely a trace of the dorsal lines. 

 The length of the largest larva at this time was 6|- cm., 

 of the smallest 5|- cm. 



July 23rd. — One larva died — a dark one, with dark 

 dorsal lines. 



July 30th. — The lightest larva was spinning up on 

 the rooL 



July 81st. — Another larva was spinning up on the 

 roof. 



Aug. 3rd. — Two more larv?e left off feeding. Of these 

 four larvfB, three were very light in colour, with the 

 dorsal lines very faint ; one was dark, with distinct dark 

 dorsal lines. One dark one left. 



By Aug. 11th all had pupated, and the last larva did 

 so on the floor without forming any cocoon. The food 

 of all was S. vitellina. 



Total results of the foregoing experiment : — 



Colour. No. of larva9. 



Very light brown, with very faint dorsal lines ... 1 

 Light brown, with faint dorsal lines ... ... 2 



Dark brown, with dark dorsal lines ... ... 2 



Dark brown, with indistinct dorsal lines 1 



Total 6 



Cylinder 8. — June 25th. — I placed six larvae in the 

 first stage in cylinder 8. 



June 26th. — The first ecdysis took place. 



June 29th. — The larvae (until now uniform dusky 

 brown) began to show signs of lightening in colour ; 

 one quite light. 



July 2nd. — The second ecdysis occurred. 



July 4th. — I was using tissue-paper for this set also, 

 and on this day applied green tissue-paper, doubled, 

 round the cylinder and over the roof, and placed the 

 cylinder in a strong light. 



July 8th.- The third ecdysis occurred. Two larvae 

 were light, three darker brown, one lightish brown. 



July 9th. — I removed the tissue-paper on Mr. Poulton's 

 advice. The length of the largest larva at this time, 

 when fully stretched, was 5 cm., that of the smallest, 

 4 cm. 



TRANS. ENT. SOC. LOND. 1892 — PART III. (NOV.) S 



