ENTOMOLOGICAL SOCIETY. 97 



there, the leaves are all eaten up." "Worms," says I. "Yes," says he, "but not 

 the kind you know." He took a stick and gave a limb a tap, and in an instant one 

 hundred worms were hanging by tiny webs. He then went around hitting all the 

 limbs he could reach, and I think there must have been a million worms suspended in the 

 air beneath that tree. "Now, May," says he, "what am I to do 1 I have manured 

 and thoroughly worked this orchard for two years, have had it trimmeed, and the 

 worms' nests all taken out of it once this spring, now just look at it." " I'll 

 tell you," says I, "I'll write to the Agricultural College and see what they advise." 

 An answer would be gratefully received, as the orchard is no small item in our 

 accounts. 



Yours truly; 



In an orchard that is regularly sprayed they can give little or no trouble, as 

 they are easily destroyed by Paris green, but in large shade trees, which are some- 

 times attacked, and where the spraying cannot easily be done, strategic measures 

 have to be resorted to. Prom the fact that the female moth in both species is wing- 

 less, and after emerging from the pupa in the ground has to climb the tree to 

 deposit her eggs, the placing of a tar band or other barrier upon the trunks of the 

 trees at once suggests itself as a remedy. 



5. The Colorado Potato Beetle. — (Doryphora decem-linedta.) — The potato bug» 

 or more properly, the potato beetle (Fig. 13) is with us yet, and he seems to be 

 here to stay. Out of about ten thousand species of Coleoptera common to this coun- 

 try, the potato beetle stands out prominently as the one most generally troublesome. 

 We have become so familiar with it; that we seldom think of it but to kill it, yet a 

 few facts as to its history in this country may be of interest. To the late Dr. C V. 

 Riley, of Washington, we are indebted for the best account of it that has anywhere 

 been published, and I have made free use of his little book on " Potato Pests," in the 

 preparation of these notes. 



The Colorado Potato Bug, as it has been commonly called, was first described 

 under the scientific name Doryphora decera-lineata, by Thomas Say, in 1824. It 

 was then to be found only in Colorado and the North- Western States, just this side of the 

 Pocky Mountains. Its original food plant was the Sand Bur (Solanuin rostratum) 

 a species of wild potato peculiar to that region. 



As civilization advanced westward and potatoes began to be grown in its native 

 home, it gradually acquired the habit of feeding upon the cultivated potato, and began 

 its eastward march from potato patch to potato patch. In 1859 it had reached to 

 within 100 miles of Omaha City in Nebraska. In 1861 it invaded Iowa, and gradu- 

 ally during the next three or four years it spread eastward over the whole State. 

 In 1864 and 1865 it crossed the Mississippi into Illinois, at four or five different 

 points coming on in a column about 200 miles broad from north to south. It was 

 then travelling at the rate of fifty miles a year and it was predicted that it would 

 reach the Atlantic Sea board in 1881. On this side of the Mississippi, however, the 

 potato fields were more plentiful and it began to make better time, actually arriv- 

 ing on the Atlantic coast in 1874, seven years ahead of time, its average rate of 

 progress being 88 miles per year. This rate, however, was not uniform, the northern 

 columns of the army made the most rapid progress ; the southern oolumns 

 travelling through a country where potatoes were not so much grown, and under a 

 broiling hot sun, lagged far behind. 



The invasion of Ontario began in July of 1870, at two points on the western frontier, 

 namely, near Point Edward and near Windsor. During 1871 they came on in increasing 

 numbers, and it was said that during that summer the Detroit river was literally swarming 

 with them. They were crossing on ships, chips, staves, boards, or any other floating object 

 that presented itself. By June of that year they were common around London, and, Mr. 

 Squirrel informs me, that later that year they had reached as far as Gait. I can well 



7 EN. 



