47 



Of the SolanacejB, or Nightshade family, to which the potato belongs, there 

 are in North America six genera, not counting the South American genus, 

 Petunia, now so largely cultivated in flower gardens. They are (1) Solarium, 

 Nightshade; (2) Pkysalis, Ground Cherry; (3) Mcandra, Apple of Peru: 

 (4) Hyoscyamus, Henbane ; (5) Datura, Thorn-apple ; (6) Hicotiana, Tobacco. 

 The first of these includes the potato, the egg plant, and the tomato, all of which 

 are eaten with avidity by the beetle. When stinted of its favourite supplies, the 

 insect turns to such other members of the family as may grow within its reach. 

 The tobacco plant is attacked by it, and I have found it also upon Physalis and 

 Datura. 



It would seem that the forced vitality of the species is now diminishing. 

 There is a narrowing do\yn apparently, 1st, as to the number of broods, 2ndly as 

 to the number of individuals. Professor Claypole, of Akron, Ohio, brought the 

 diminution in the former case, under the notice of the American Association for 

 the Advancement of Science, at the Minneapolis meeting. He said : — " This 

 insect (the potato beetle) came as usual in middle Pennsylvania in the early sum- 

 mer. I was compelled to use poison as in previous years. In the latter portion 

 of the summer I observed, and noted at the time in the Canadian Entomologist, 

 that there was no second brood, or that it was so small as to pass unnoticed. It 

 was my intention to watch in 1883 in order to determine if this second brood 

 was again missing ; but to my surprise, in 1883 there was almost no first brood." 



In the neighbourhood of Quebec, late plowing, by disturbing their hiberna- 

 cula, has destroyed great numbers of the beetles, and the lingering winter has 

 retarded the appearance of the survivors, so that the first brood of the year has 

 been both late and comparatively weak in numbers. For the last two seasons I 

 have not had occasion to use Paris green on the early potatoes grown in my gar- 

 den, but later-planted field crops have called for an application of the drtlg. The 

 decrease in the number of perfect beetles appearing in the fall has been very 

 marked. 



Fig 13. 



The Three-Lined Potato-Beetle (Lema trilineata, Olivier). — This is a 

 buff-coloured beetle, (Fig. 13) having three black stripes on the wing covers. Its 

 length is a quarter of an inch. It appeals in June, and attacks 

 the potato plants. It lays its yel- 

 low eggs in small clusters, and in 

 a fortnight the larvae appear (Fig 

 14). They are of a dirty yellowish 

 grey, and are generally seen with a 

 * thick coating of excrementa on 

 their backs. This filthy covering 

 is believed to serve for a defence 

 against their insect enemies, and as a protection 

 also from the heat of the sun. In about another 

 fortnight the insects bury themselves in the 

 ground and form cysts in which to undergo their pupal change. In a fortnight 

 more the perfect beetles appear and lay their eggs for a second brood. 



Paris green applied in the usual way is the remedy for these pests. 



The Cucumber Beetle (Diahrotica vittata, Fab.). — The cu jamber ,beetle 

 is about two lines in length. It is yellow, and has a black head, and three black 

 lines running along the wing-covers. The larvas feed on the roots, and^the perfect 

 insects on the tender leaves of the cucumber, melon and squash. 



Fig. 14. 



