179 



From this it is evident that there is but one brood of these 

 insects each year. Farther south there are two broods a 

 year, and it is possible that there may be two in Massachu- 

 setts, in some cases, but, if so, it is unusual. 



e 



Oyster-shell scale: a, under side of female scale, showing eggs; 6, upper 

 side of same, both much enlarged; c, female scales on a branch, 

 natural size; d, male scale much enlarged; e, male scales on branch, 

 natural size. The fine lines to the right of o, 6 and d show the real 

 length of the scales. (Howard, United States, Department Agri- 

 culture, Yearbook, 1894.) 



Treatment. 



As the eggs of these scales all hatch about the first of 

 June, this fact may be taken advantage of in the treatment. 

 The crawling young are entirely unprotected by any scale, 

 are soft-bodied, and can be killed by spraying with kerosene 

 emulsion or with whale-oil soap, if taken at the right time. 

 The only difficulty is that in order to be destroyed each 

 one must be touched by the spray, and they are very small. 

 This means that the spraying must be thorough. 



Whale-oil Soap. — Whale-oil soap, 1 pound ; water, 4 or 5 



