f Eleventh Keport of the State Entomologist 179 



Progress of the Insect in the Eastern United States. 

 For a long term of years following the first observed injuries in 1859, 

 the beetle in this country was confined to Long Island and the immediate 

 vicinity of New York City, While in the main keeping near the sea- 

 coast, it has now extended to the southward as far as Fortress Monroe in 

 Virginia. Within the last ten years, it has been found at Geneva and at 

 Rochester in Central and Western New York, and quite recently it has 

 been reported from localities in Ohio. To the northward, in the New 

 England States, it made its appearance at Amherst, Mass., in 1892, and 

 the same year in Nashua, N. H. Magnolia, on the sea-coast in north- 

 eastern Massachusetts, is nearly as far north as Nashua. 



Range of Insects Limited by " Life-Zones." 

 Particular mention is made of the above-named localities for the aspara- 

 gus beetle, as indicating that its range to the northward as an injurious 

 insect will be largely if not entirely limited to a certain zone known as 

 the " Upper Austral life-zone." From data drawn from long-continued 

 observations and studies, certain "life-zones" have been mapped, upon 

 the belief that both animals and plants are restricted in their distribution 

 — according to Dr. C. Hart Merriam — " by the total quantity of heat 

 during the season of growth and reproduction." These life-zones, as 

 they have been plotted, while not strictly agreeing, "conform in a most 

 gratifying manner " (Merriam) to the isotherms shown on our most reU- 

 able maps, and to the contour lines of elevation indicated in the recent 

 " Gannett's Nine-sheet Contour Map," published by the U.S. Geo- 

 graphical Survey. 



Probable Examples of such Limitation. 

 The probability of the limitation of insect pests to certain hfe-zones, 

 irrespective of the broader distribution of their food-plants, has lately 

 been made the subject of study by Mr. Howard, Chief of the Entomolog- 

 ical Division of the U. S. Department of Agriculture. It was first sug- 

 gested to him by the discovery that the San Jose scale in its recent 

 introduction into the Eastern United States — although it had been 

 distributed by nurseries over the entire State of New Jersey — was not 

 found in its northern portion (Dr. Smith); and that the infested portion 

 of New Jersey, Long Island, and all of the infested localities in Maryland, 

 Virginia, Pennsylvania, and New York, lay within the Upper Austral 

 zone. He has also called attention to the probability that the asparagus 

 beetle may be subject to the same northern limitation, although its occur- 

 rence at Amherst, Mass., and Nashua, N. H., appeared to him to mill- 



