26 AGRICULTURE OF MAINE. 



eat holes through the leaf and continue feeding around the cir- 

 cumference of the hole, clinging to the leaf with their thoracic 

 legs and holding the body S-shaped in the hole. Some species 

 are leaf-skeletonizers for the first two or more stages and then 

 either feed from the edge or eat holes in the leaf. The great 

 majority of species are edge feeders. 



The larvae of certain genera and subfamilies of the sawflies 

 are entirely different in appearance during their last larval 

 period ; white larvae may become spotted, the spotted change to 

 white or green and the spiny lose their spines. Thus the same 

 specimen may be powdery white one afternoon and the next 

 morning yellow \V^th black spots. These changes which take 

 place at time of molting increase the difficulties of studying a 

 species. 



The members of one subfamily feed on various species of 

 conifers; they clasp the needles between the thoracic legs and 

 feed until only short stubs are left. Some species will feed on 

 the needles of the year old growth, others are indiscriminate, 

 feeding either on the new or the old growth. The pines, spruces, 

 and larches especially suffer from the attack of sawfly larvae 

 in Maine and on this group of larvae Doctor MacGillivray has 

 in preparation a bulletin to be published by this Station. 



Powdery Scab of Potatoes. 



For many years the plant pathologist of the Maine Agri- 

 cultural Experiment Station has been studying the common 

 scab of the potato, and in this connection has asked for speci- 

 mens of scab to be forwarded in different years from various 

 parts of the country. About two years ago two specimens 

 were received — one from Massachusetts and the other from 

 Nebraska — which were infected with powdery scab. So far as 

 is known, this was the first intimation of any powdery scab pro- 

 duced on potatoes grown within the United States. 



Some six months before the first specimens of powdery scab 

 were discovered in Maine, and over a year before it was known 

 that the disease occurred in the state except on one or two 

 farms, this Station issued a warning as to the dangerous nature 

 of the disease, described its appearance, pointed out the strong 

 possibility of its being introduced into the state on account of 

 its presence in Canada, and requested potato growers and others 



