7o6 THE POPULAR SCIENCE MONTHLY. 



son tliat it is controlled with comparative ease. The natural enemies 

 of the species are encouraged by the intelligent cultivator, and poultry 

 may be taught to ieed upon it. Of over twoscore predaceous and 

 parasitic species of its own class which I have enumerated, those here- 

 with figured may be considered the most important. The only true 

 parasite is a species of Tachina-fly {Lydella doryjyhoroe, Riley), some- 

 what resembling a house-fly, which fastens its eggs to the doryphora 

 larva. From these eggs hatch maggots, which feed upon the fatty por- 

 tions of the said larva, which, after entering the ground, succumbs to 

 its enemy, and, instead of eventually giving forth a beetle, as it natu- 

 rally should do, gives forth, instead, the Tachina-flies. A number of 

 different lady-birds ( Coccinellidce), of which the convergent lady-bird 

 is the most common, devour the eggs of the doryphora. Of true bugs 

 the spined soldier-bug [Arma sjnnosa, Dallas) is the most effective, 

 though several other rapacious species assist it, all of them piercing 

 and sucking out the juices of their prey. Of artificial remedies there 

 are various mechanical contrivances for knocking the insects off" the 

 haulm and catching them some such even being worked by horse- 

 power. The sun is, also, so hot in some of the Mississippi Vallej' States 

 that thelarvse are roasted to death if shaken from the haulm on to the 

 hot soil at mid-day. The remedy of all others, however, and the one 

 universally employed, is Paris-green, which is used either in the form 

 of a powdei", or in that of a liquid, being combined in the former case 

 with from twenty-five to thirty parts of some dilutent, as flour-middlings, 

 plaster, etc., and in the latter with one tablespoonful of pure green 

 stirred into an ordinary bucketful or about three gallons of water. 

 Enormous quantities of the poison have thus been used in America, 

 especially since it has proved a perfect remedy for the cotton-worm in 

 the Southern States as. well as for the potato-beetle in question. Cau- 

 tiously and judiciously used it proves cheap and effective, and a large 

 experience goes to show that no ill effects follow such use of it. 

 There is a very closely-allied sipecies, the Doryphora Jmicta of Germar, 

 called the bogus Colorado potato-beetle, which, very naturally, has 

 often been confounded witii, and mistaken for, the genuine depreda- 

 tor. It differs, however, in the eggs being paler; in the larva being 

 paler, and in having but one row of black dots on each side instead of 

 two ; and in the beetle having the second and third black lines of the 

 elytra (counting from the outside) joined, instead of the third and 

 fourth ; in the punctures of said elytra being more regular and dis- 

 tinct, and in the legs haying pale instead of dark tarsi, and a spot on 

 the thighs. Singularly enough, this species, though it feeds and 

 thrives on Solanurn Carolinense, will not touch the cultivated potato, 

 and is, therefore, perfectly harmless to man. 



The English reader is more particularly interested in this insect, 

 because of its possible introduction into Europe; and on the subject 

 of its introduction I cannot do better than quote some passages from 



