66 



a very drastic manner by the board of agriculture's officials, but as 

 Ave shall see, Avithout clearing the land completely of this serious pest. 

 The potato haulm « was cleared and fired with paraffin and the ground 

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

 •also soaked with paraffin, and gas lime was put on at the rate of 

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

 the board o'f agriculture and myself found that the beetles could live 

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

 unknown quantity to be effective against the adults, although its 

 caustic properties should destroy larv?e and pupse. 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 were examined later and no further specimens 

 were found. I Avent to Tilbury again on September IT, 1901, and 

 could find no trace of beetles, larvae, or eggs around the invaded are<i. 

 I brought some twenty beetles and larva3 aAvay Avith me on the first 

 A^isit.and kept these in confinement in breeding cages under safe guard- 

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

 In very feAV cases did I notice the beetles feeding, but the larvae, 

 especially in their closing stages, Avere most ravenous. Besides 

 potato, I fed some on tomato and found the}" did not thriA^e so w^ell, 

 others on deadly nightshade (Atropa helladonna) and on sow thistle 

 (Sonchus oleraceus) ^ on both of Avhich they flourished admirably. 

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

 it as a food plant. Soon after bringing the specimens home I found 

 that the adults readily buried themselves in the earth Avhen the 

 Aveather was dull and cool. Several adults which I took in August 

 lived until the folloAving spring, a fcAV died, and others deposited eggs. 

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

 some being yelloAV, others deep orange. They varied in number in 

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

 Avhether they laid the eggs on the upper or imder sides of the leaves. 

 Those laid in m}^ garden Avere nearly all on the upper surface, while 

 those at Tilbury Avere mostly seen on the under surface. 



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

 larval stage from three to fiA^e Aveeks, and the pupal stage from scA^en 

 to ten days in summer. One larva liA^ed seven Aveeks and then died. 

 A few larvae existed for tAvo Aveeks Avithout any food and eventually 

 transformed to adults after being fed. 



To my surprise, one warm day in NoA^ember, some dozen beetles 

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

 condition, but before nightfall they had buried themselves again. 

 I dug up the ground in January and found they Avere all lying about 



Dry stalks, stubble. — Ed. 



