PACKARD] THE YELLOW-STRIPED SYSTENA. 729 



who are not inclined to use Paris green may use carbolate of lime, made 

 hy mixing in the proportion of half an ounce of crude carbolic acid with 

 a pound of lime, forming a powder, which can be dusted on the leaves. 

 Others have used air-slacked lime with success. Hellebore is ineffectual. 



The following suggestions by Prof. H. H. McAfee, of Iowa Agricult- 

 ural College, are valuable : " We know that the Doryphora lOUneata 

 can only remain healthy and increase rapidly when feeding upon sola- 

 naceous plants. Cut off his rations for any considerable length of time 

 and he will surely die; hence if ^e plant only early potatoes^ whose tops 

 are all dead by August 10, but few potato-bettles will be found alive on 

 your grounds nest season. * * * a word as to how this policy has 

 worked in practice. During the seasons past, in which I have grown 

 2,100 bushels of potatoes on the Iowa Agricultural College farm, the ex- 

 pense of keeping potato-beetles in check by hand-picking, when they 

 became too numerous, has been less than S-, and no poison has been 

 used and no late potatoes have been grown in my department. Of course 

 where potato-patches are contiguous auy patch may suffer from the 

 neighbors' bugs, so that this policy of autumn starvation must be gen- 

 eral to be most effective." 



Also, as a preventive, it would be well to try planting the prickly 

 solauum {S. rostmfum) around potato-fields, and asertain whether the 

 beetles would not desert the useful plants for the weed ; if so, the culture 

 of the weed would be an invaluable adjunct to that of the potato. A 

 correspondent of the New York Tribune states that the Colorado potato- 

 beetle feeds on the common nightshade {Solarium nigrum). To quote 

 his words: "The Colorado potato-beetle troubled the potatoes in my 

 garden very little; but at the side of the garden, close at the ends of 

 the rows, were two or three large shrubs or vines commonly called 

 nightshade. Upon these were hundreds of the slugs of the 'pest,' 

 which seemed to thrive splendidly ; and so long as the marauders con- 

 fine their foraging to this noxious plant I shall not molest them." — (G. 

 H. B., Franklin, N. Y.) 



It would be also worth while for experiments to be made in planting 

 not only the common nightshade, but the bittersweet {Solanum dnl- 

 camara), a common vine imported from Europe, growing in our gardens 

 and about our houses. The horse-nettle {Solanum caroUnense), a com- 

 mon weed flourishing from Connecticut to Illinois and southward, and 

 upon which the Lcptinotarsa juncta feeds, might also be planted in 

 broad borders around the potato-fields with i)robably good results. 

 "Whether it is a good policy to heed the natural food-plants of insects, 

 and thus perhaps increase the number of the noxious insects preying 

 upon them, has always been a question in my mind. Still it would be an 

 experiment worth trying in the present case, where it seems almost im- 

 possible to increase the numbers of this beetle beyond what they have 

 already attained. 



Thk Yellow-Striped Systena, Si/stena mitis Le C. var. ligala Le C. (Plate LXVI, 

 Fig. 3.) — Eatiug boles iu lae leaves and making blotches ou them ; a small beetle nearly 

 two lines iu length ; black, with two broad yellow stripes along the back. 



This beetle I have onl}- noticed in Colorado, where I observed it in a 

 field of potatoes at Idaho Springs, July 5. It was very abundant on the 

 leaves, eating holes in them and making blotches. As they were pair- 

 ing it is evident that the eggs are laid at this time, and soon after the 

 larvse should be looked for, either upon the leaves or at the roots or in 

 the stalk. 



Description. — Body rather flat, and rather long and narrow; blackish-brown; head 

 with yellow orbits ; a broad dark baud between the eyes, and a dark patch behind the 



