February, '10] SEVERIN : SAN JOSE SCALE 101 



lor matches July 1, 1908, were still alive August ISth. Matches not 

 ignited. 



Length of Life 



A large specimen of P. americana was placed in a breeding cage 

 June 26. 1908, and kept constantly supplied with food in the shape 

 of Irish potato, starch, etc. This cockroach lived until October 30, 

 1909, or a period of 1 1-3 years. 



THE SAN JOSE SCALE AND ITS RELATION TO CLI- 

 MATIC DISTRICTS OR LIFE ZONES IN WISCONSIN 



By Henky H. p. Sevebin, University of Wisconsin. , 



A number of economic entomologists have put the question to me, 

 "Is Wisconsin free from the San Jose scale?" Marlatt^ writes, 

 "Wisconsin is, on the authority of Mr. E. P. Sandsten, horticulturist 

 of the state experiment station, now free from the San Jose scale. 

 The only occurrence of this pest in the state was three years ago in 

 the extreme southern part, and it was here stamped out by the prompt 

 adoption of radical measures." The people of Wisconsin ought to 

 congratulate themselves if such a condition actually exists. From 

 what work my brother and I have done in preparing our paper, "A 

 Preliminary List of the CoccidEe of Wisconsin"* (the species men- 

 tioned were, with one exception, collected in or near Milwaukee), and 

 from the few days I have spent in the field in or near Madison I am 

 thoroughly convinced that the people of this state would be surprised 

 at the results of a systematic inspection in regard to this pest. 



The relation of climate to the spread of the San Jose scale has been 

 considered by Howard and Marlatt in three bulletins.^ - ^ 



Dr. C. Hart Merriam has established a number of climatic districts 

 or life zones within which particular animals or plants perpetuate 

 themselves and outside of which they fail to become established. These 

 life zones are : The tropical, occupying small areas in Florida and 

 southern Texas; the lower and upper austral, covering the bulk of 

 the United States; the transition zone, coming between the last and 

 the boreal zone of Canada northward. ' ' The early records led to the 

 belief that the San Jose scale would be practically limited to the upper 

 and lower austral zones, and that the important fruit districts in the 



1 Bull. No. 3, U. S. Dept. of Agric. Bureau of Ent, 1896. 



2 Bull. No. 12, U. S. Dept. of Agric. Bureau of Ent, 1898. 



3 Bull. No. 62, U. S. Dept. of Agric. Bureau of Ent., 1906. 



4 Journ. of Econ. Ent. II, No. 4, 1909, pp. 296-298. 



