46 



MASS. EXPERIMENT STATION I?Ur.I.ETIN 239 



Treatment. 



Because of tlie size wliicli these worms attain, their net count should rate 

 as that of cutworms (see page 3). A spray of 6 pounds of dry lead arsen- 

 ate in 100 galknis of wiiter should be used when tliey hatch. 



Chain-spotted Geometer.'' 



Neglected l)ogs with a dense growtii of 

 birches on the surrounding upland, usually areas 

 tiiat never are flooded, occasionally liave this 

 spanworni crawl onto them in such numbers 

 that the \ines are browned for some distance 

 from the margin. The worms often are reduced 

 greatly by parasites and a fungus disease". A 

 few of them appear on most dry Ijogs yearly. 



Distrilnition aud Food Plants. 

 This species ranges through the Atlantic 

 States and southeastern Canada and west to 

 Colorado. Gray birch seems to be its favorite 

 food plant, but it often defoliates alder, ash, 

 low blueberry, dwarf blueberry, swamp blue- 

 berry, male berry, wild black cherry, bayberry, 

 sweet fern, black huckleberry, wild indigo''', red 

 maple, white maple, sheep laurel, black scrub 

 oak, meadow-sweet, poplar, red spruce, tama- 

 rack, white pine and willow. It also feeds on 

 raspberry, blackberry, goldenrod, sweet gale, 

 hazelnut, poison ivy, juniper, cranberry', rho- 

 dora^^, sedges, grasses, and probably numerous 

 other plants. 



l>escripfio)i and Sea.t(>nal Hisforii. 

 The Worm. 



The worms appear in early summer and de- 

 velop slowly maturing in late July and early 

 August. They get to be nearly an inch and a 

 half long. As they mature they have the habit 

 of hanging straight and still, head downward 

 (fig. 32), during the day. They seem to feed 

 mostly in the evening or at night. They are 

 yellow, with round black spots on the head, 

 the neck shield the outer sides of the prolegs, and 



Chain-spotted Geometer. 

 Fig. 32. Worm. Much enlarged. 



.51. Cingilia calenaria (Dru.). 



52. Caused by Empusa Anlicae Riechardt (det. Prof. W. H. Sawyer, Jr). 



53. Baptisia lincloria (L.) R. Br. 



54. Rhododendron canadense (L.) BSP. 



