130 NEW YORK STATE MUSEUM 



NOTES FOR THE YEAR 



The season of 1903 has been marked in particular by an un- 

 usually severe outbreak of plant lice of various species, some of 

 which continued their depredations over an abnormally extended 

 period. These insects were so destructive and generally present 

 on various plants in different sections, that observations relating 

 thereto have been grouped under a separate head. Species depre- 

 dating on other plants and products of value, have been grouped 

 under convenient headings for the purpose of facilitating ready 

 reference to the various accounts. ' 



Plant lice 



The season of 1903 may well be remembered on account of the 

 exceeding abundance of these little insects, particularly of species 

 of economic importance. This is an exceedingly interesting 

 group, and their almost absolute helplessness and enormous pro- 

 lificacy illustrate one of nature's provisions against the extermi- 

 nation of a species. Despite their apparent weakness, these little 

 creatures are well able to hold their own, as many farmers know 

 to their cost. This group is at present represented in America by 

 the relatively large number of 325 species, as given by Professor 

 Hunter in a recently issued list. 



The conditions which control the abundance of these forms are 

 not well understood, though in all probability they are largely 

 climatic, supplemented by the beneficial work of various natural 

 enemies. Some believe that dry weather is favorable to the in- 

 crease of these little insects, and others attribute their abnormal 

 development to a certain amount of moisture. It is very probable 

 that a protracted dry spell, if not accompanied by excessive dust, 

 is favorable to the development of a large number of species, and 

 that violent rains at intervals, specially if they occur before the 

 foliage is curled by the work of the pests, is very destructive to 

 these little creatures. On the other hand, it is quite possible that 

 a certain amount of moisture is desirable, and that the reports 

 of certain persons, who have noted a coincidence between the ap- 

 pearance of rains and the development of these forms, may be 

 correct. 



