INSECTS AFFECTING PARK AND WOODLAND TREES 569 



to feed in August and September on the underside of willow and poplar 



leaves, the adults appearing- in June. 



Description. JThe larvae of this insect have been described by I)r 



Lintner as follows : 



When near maturity, they were 7 /i of an inch long, of an orange-yellow 

 color, with two rows upon the back (subdorsal) of 12 large irregularly 

 rounded black spots, measuring in diameter about ]/ 2 the length of the seg- 

 ment. There is also a row on the side (stigmatal) of 12 smaller black spots, 

 of which the 2 anterior ones are the largest, and semicircular in form. 

 Numerous short white hairs are given out from two transverse rows of 

 tubercles on each segment, the longest of which about equals one half the 

 diameter of the body. The head is black superiorly and laterally, with a 

 central black spot in front surrounded with brown. The tarsal hooks are 

 brown. 



Adult. Head, shining black, short, broad, not so wide as the thorax ; 

 antennae brown, the seven long joints are slender, tapering regularly to the 

 last. Thorax black above, yellow laterally and beneath, except posteriorly 

 where it is black. Abdomen yellow, distinctly incised, short, flat, subovoid ; 

 legs yellow. Wings yellowish towards the base and particularly on the 

 costa ; the stigma large, conspicuous, with a black spot on its base. 



Bibliography 

 1888 Lintner, J. A. Ins. N. Y. 4th Rep't, p. 44-46 

 1889 Ins. N. Y. 7th Rep't, p. 223-24 



Pteronus hudsonii Dyar 



Black-headed, bluish or leaf-green sawfly larvae with series of orange-yellow, large 

 blotches on segments 3-12 and numerous black spots, sit on the edge of poplar leaves. 



The larva has been described by Dr Dyar as follows : 



Larva. Sitting on the edge of a leaf and thrashing the abdomen 

 about when disturbed. Head normal, round, black, sutures paler; width 

 2.2 mm. Thoracic feet moderate, pale, abdominal ones on joints 6-1 1, 13, 

 well developed ; short black anal spines. Body smooth, shining, faintly 

 3-annulate, dorsal vessel yellowish ; color bluish or leaf-green, with a series 

 of orange-yellow, large lateral blotches on joints 3-12 and numerous black 

 spots as follows : two transverse rows per segment above the spiracles, the 

 anterior of three on each side, the posterior of four, its lower (lateral) one 

 largest ; two black patches on the halves of the subventral ridge, the lower 

 posterior one somewhat broken ; on joint 13 a large lateral black patch and 

 dorsal suranal blackish cloud. 



