INSECTS AFFECTING PARK AND WOODLAND TREES 



553 



twig near the end of the branch and remain unhatched till the following 

 spring. 



Natural enemies. This species is very subject to the attack of para- 

 sites, and we have bred from one nest a number of specimens of Macro- 

 centrus solidaginis Cress. This and other species are undoubtedly 

 of considerable value in keeping the pest in control. 



Serica sericea 111. was taken on alder at Karner June 8, 1902. It is 

 common in Herkimer county on the blossoms of wild cherry, visiting these 

 trees when in bloom. 



Pteronus thoracicus Harrington 



A greenish, solitary sawfly larva resting on its venter on the under surface of shad- 

 bush leaves ( A m e 1 a n c h i e r canadensis) may belong to this species. 



This larva was met with by Dr Dyar at Plattsburg N. Y. and its 

 various stages have been characterized by him as follows : 



First stage. Head round, higher than wide, but not narrowing to 

 vertex, shining, eye black, mouth brown ; width .25 mm. 



Second stage. Similar; eye surrounded by a black spot; head rather 

 higher ; width .33 mm 



Third stage. Head almost whitish, pale ; width .5 mm ; joint 2 small, 

 making the head appear prominent. Body much as in the following stages, 

 but paler. 



Fourth stage. As in the next stage in all "points, but a little paler, 

 though darker than in the previous stage ; width of head .7 mm. 



Fifth stage. Head round, smooth, shining, greenish testaceous, 

 prominent ; eye black, mouth brown ; width 1 mm. Thorax a little 

 enlarged, the feet spreading widely, not concealed. Abdomen slightly 

 tapering posteriorly, gradually becoming smaller from the thorax ; feet 

 present on joints 6— 1 1 and 13 ; segments 4-annulate, smooth, without tuber- 

 cles, not shining ; color pale clear green, the alimentary canal showing dark 

 green or the surface covered with a slight white bloom. Thoracic feet 

 watery greenish ; abdominal ones short, concolorous with the pale subventral 

 region ; anal plate rounded. 



Sixth stage. As before, width of head 1.4 mm. 



Seventh stage. Head held forward ; light testaceous, faintly brownish, 

 smooth, shining, minutely reticulated ; eye black, mouth brown ; width 

 2 mm ; joint 2 depressed anteriorly. All as in the previous two stages ; 

 skin smooth, but not shining : at the end of this stage the larvae fade to a 

 whitish color with a bright green dorsal band and enter the earth without 

 molting. 



