BY HENRY TRYON. 
21 
the close relationship which exists between the plant from which 
it derives its name, and the wild mustard, and is ecjually partial 
to both ; the caterpillars of our commoner species of Papilio 
similarly recognise the fact that the Chinese box-leafed Atalanta, 
the introduced orange and its allies, and the native species of 
Citrus, though to our observation so different in appearance^ 
have close affinities— as pronounced by botanists who have 
placed them in the same rutaceous tribe, Aurantise— and are 
found feeding upon all these plants. In the case of Lita solanella, 
the pest under consideration, it has been observed by me that it 
has now become inimical to the growth of the tobacco plant as 
well as to that of the potato, both— so unlike in their habit- 
being members of the same natural order, Solanacefe. Shortly 
after the visit to the growing potatoes already alluded to advice 
was sought as to the best method for contending with a pest 
which defied repeated efforts to raise to maturity tobacco in the 
same Moggill district ; and the damaged young plants submitted, 
in illustration of the nature of the ravages of the assailant com- 
plained of, were found to have their leaves extensively mined by 
tiny caterpillars, which— by use of the breeding cage— were de- 
monstrated to be those of the potato grub. It was also found 
that caterpillars reared from eggs laid by the same generation of 
moths so obtained, fed indifferently upon the potato and tobacco. 
Having made this discovery, and in view of the commercial rela- 
tions which obtain between Brisbane and the remote districts 
(“ worm-eaten ” potatoes having been seen by me on their arrival 
at a small centre of population where also potatoes are grown, 
thirty-five miles distant by dray road from Dalby, and in the 
same month of December), the transmission of this pest to the 
well-known tobacco-growing district of Texas, and its establish- 
ment there was not altogether an unexpected event. And such 
event was brought to my notice in November, 1891. when advice 
' was sought as to the best method for contending with the in- 
' cursion of an interesting Peronospora* which had been discovered 
' by me in 1889 as the cause of an also formidable disease of the 
■ young tobacco plant now known as “blue mould.*’ Amongst 
j the leaves forwarded from Texas on this occasion, and exhibiting 
' • Vide leaflet issued by Department of Agriculture entitled “ Tobacco 
Disease,” 19th June, 1890. 
