66 



a A'ery drastic manner by the board of agricultnre's officials, but as 

 we shall see, without clearing the land completely of this serious pest. 

 The jDotato haulm "■ was cleared and fired with jDaraffin and the ground 

 heavily coated with gas lime and later plowed up. The land was 

 also soaked Avith paraffin, and gas lime Avas put on at the rate of 

 (iO tons per acre. I may here mention that one of the inspectors of 

 the board of agriculture and m^^self found that the beetles could live 

 in a tin of gas lime unharmed; one Avould not, therefore, expect this 

 unknoAvn quantity to be effective against the adults, although its 

 caustic properties should destro}^ larvfe and pupie. It does not do 

 so, however, for reasons which I shall point out. 



The land and the neighboring plats of potatoes and the district for 

 some 3 miles around Avere examined later and no further specimens 

 AA'ere found. I Avent to Tilbury again on September 17, 1901, and 

 could find no trace of beetles, larva?, or eggs around the invaded area. 

 I brought some tAventy beetles and larva; aAvay Avith me on the first 

 visit and kept these in confinement in breeding cages under safe guard- 

 ianship in my garden. The larva? all became mature by September 23. 

 In very fcAV cases did I notice the beetles feeding, but the larvse, 

 especially in their closing stages, Avere most ravenous. Besides 

 potato, I fed some on tomato and found tliey did not thriA^e so well, 

 others on deadly nightshade {Atropa helladonna) and on soav thistle 

 {Sonchus ole7Xice}(i<) , on l)oth of AA'hich they flourished admirably. 

 Some eggs Avere found on the sow thistle at Tilbury; hence I tried 

 it as a food plant. Soon after l)ringing the specimens home I found 

 that the adults readily buried themselves in the earth Avhen the 

 Aveather Avas dull and cool. Several adults Avhich I took in August 

 liA-ed until the folloAving spring, a fcAV died, and others deposited eggs. 

 The eggs found at Tilbury varied greatly in color according to age, 

 some l)eing yelloAv, others deep orange. They varied in number in 

 the last batch from 9 up to 40. The beetles, it seemed, did not mind 

 AAdiether they laid the eggs on the upper or under sides of the leaA-es. 

 Those laid in my garden Avere nearly all on the upper surface, while 

 those at Tilbury Avere mostly seen on the under surface. 



The Qgg stage lasted Avith us ten days, and in one case seA^enteen, the 

 larval stage from three to five weeks, and the pupal stage from seven 

 to ten days in sunnner. One larva lived seven Aveeks and then died. 

 A few larva^ existed for tAvo Aveeks Avithout any food and eventually 

 transformed to adults after being fed. 



To my surprise, one Avarm day in Xovember, some dozen beetles 

 came out of the ground and remained on the surface in a sluggish 

 condition, but before nightfall they had buried themseh^es again. 

 I dug up the ground in January and found thev Avere all Ivin^ about 



"Dry stalks, stubble. — Eu. 



