66 



les^"s are l)lack ; the abdominal legs pale, with an external dark 

 chitinous plate above the jilanta. 



The general color of the body is glaucous-green, being of 

 the same hue as the color of the under sitle of the aspen leaf on 

 which it feeds. There is a brown dorsal spot on the 8th abdominal 

 segment, on which the tubercle rests, while along the sides low 

 down, at the base of the abdominal legs, and in corresponding 

 places where the legs are wanting is a row of irregular reddish 

 spots. The skin under a Yz inch objective is seen to be studded 

 with hne, dark, short, conical setc'e or granulations which are largest 

 and thickest on the sitles of and at the base of the middle abdom- 

 inal legs. The hairs over the body are glandular, slightly bulbous, 

 and about half as long as the body is thick. 



The two tenant hairs on the thoracic feet are knife-shaped, 

 somewhat as in Iclithxura iiniiisix. The plantae of the abdominal 

 legs have a much larger number of crochets than usual in larvae 

 of stage I, as there are 26 of them, forming a nearly complete but 

 broken circle, and the crochets themselves are rather short and 

 blunt. 



Stdi^c II. — Length, 8 mm. Moulted Aug. 3. The Pheosia 

 characters are now declared, owing to the transformation of the 

 dorsal tubercle on the 8th abdominal segment into a fleshy cone 

 or low horn I The larva feeds on the edge of the hole which 

 it eats out of the leaf, and at first sight may be mistaken for a saw- 

 fly larva, owing to tlic tlark I'eddish brown s]iots and band on the 

 sides which resend)le abdominal legs, and assinnlate it in appear- 

 ance to the ii^X'-^ii of the hole, which turns dark after it has been 

 eaten out by the caterpillar. 



/'//(• prothoracii shield has now liisappcarcJ. 'i"he head slightly 

 narrows above and is slightly bilobed, smooth and shining, a 

 little wider than the body, which narrows a little towards the 

 K:\\i\ ; it is dark chesnut-brown on the sides, pale chesnut in front. 

 The body is pale green above, still of the same hue as the under 

 side of the leaf. The untler side is i)eculiar in tiie thoracic anil 

 short, thick abdominal legs being dark livid brown ; with a large 

 chesnut-brown patch on the base of each, and on the ist and 2d 

 abdominal segments is a dark brown blotch where the base of the 

 legs would be if tlu\' were present; farther along in the space 

 betw'een the 4th pair of legs and the anal legs is an irregular 

 dark brown broad line extending along the side of the body to 

 the sides of the anal legs. The latter are used in creeping, but 

 but are about half as large as the middle ones. 



