26 THE CANADIAN ENTOMOLOGIST. 



The egg. — The act of egg-laying has not been observed, but probably 

 takes place in the evening or at night as the moths are rarely seen on the 

 leaves during the day. The eggs are attached to the under surface of the 

 leaf, usually at the forks of the more prominent veins. The egg is about 

 .3 mm. long by .2 mm. wide, oval in outline, flattened where attached to 

 the leaf and dome-shaped in profile. The green of the leaf shows through 

 the transparent egg-shell, making it a difficult object to find. They are 

 most easily located by holding a leaf at an angle in the sun so the light 

 will strike it obliquely when the eggs will be seen as minute glistening 

 dots. The exact time required for the hatching of the egg has not been 

 determined, but it cannot be far from two weeks. On June 2, 1908, an 

 examination of the orchard showed that a great number of eggs had been 

 laid ; on June 9 no eggs had hatched, and on June 18 hatching had just 

 nicely begun. 



The larva — In hatching the larva eats its way out of the egg-shell 

 on the under side next to the leaf and enters the leaf directly without 

 coming out on the surface. When full grown the larva is about 1/6 inch 

 in length, greenish white in colour, with the head light brown ; the 

 contents of the alimentary canal show through the semitransparent body 

 wall as a greenish or brownish stripe. The larva is legless and only 

 slightly flattened ; the constrictions between the segments are rather deep 

 but obtuse ; the surface of the body is smooth and clothed with dense, 

 very short, microscopic hairs interspersed with a few larger ones. 



The mine. — After entering the leaf directly from the under side of 

 the egg the young larva eats out a narrow linear burrow or mine an inch 

 or less in length, leaving the outer layers of the leaf intact. This portion 

 of the mine usually follows a tortuous course but may be nearly straight. 

 The larva next enlarges its mine into an irregular ovate blotch about one- 

 half inch in length. In the linear portion of the mine the excrement is 

 left as a blackish streak extending along the centre of the burrow \ in the 

 blotch mine it forms a broad irregular band along the centre, but does 

 not extend to the tip. The outer leaf layers overlying the mines turn 

 brownish or yellowish ; the upper layer seems to be thinner than the 

 lower and the mines are more conspicuous when viewed from above. 

 There are ten or a dozen mines in a single leaf. 



The cocoon. — When full grown the larva leaves the mine through a 

 cut in the upper surface of the leaf, falls to the ground and there con- 

 structs a small flattened brownish cocoon in cracks in the soil, under 



