18 



THE PRACTICAL ENTOMOLOGIST. 



ANSWERS TO OOKRESPONDENTS. 



Levi Bartlett. N. H. — The larvfe of all known blister- 

 beotles feed under ground on roots, Ac. It is possible 

 that some few of them m;iy occasionally feed on the roots 

 of the potato, but, from facts too tedious to particularize 

 here. We do not believe they do. They certainly do not 

 feed in the open air on the leaves of cither the potato or 

 any other plant, as does the larva of the Ten-striped 

 Spearman. We find that you have made a very cu- 

 rious mistake. You have umloubtedly confounded the 

 "Three-lined Leaf-beetle," {Crioreris trilineata,) which 

 as you say, is well described and figured by Harris, 

 (Injurious Insects, p. 118 — 9,) with the "four or six- 

 striped Blister-beetle," (Lytta vittata.) which is the in- 

 sect referred to by Mr. Walsh. If you turn to Harris's 

 work, (pp. 137 — 9) you will find three different species of 

 Blister-beetles well figured there — though the "four or 

 six striped one" is not among the number — and you will 

 notice that they are quite different in shape, Ac, from 

 the "three-lined' leaf-beetle." The larva of the latter 

 does commonly feed on potato leaves; that of the former 

 jjever. Recollect that when an Entomologist saya *' four- 

 8triped"he means " four-strijied"' and not" three-striped." 

 Entomologically speaking. the "three-lined Leaf-beetle," 

 as well as the new Potato-bug from the Rocky Mountains, 

 is separated at once from all the Blister-beetles by having 

 only /our joints to each of its six feet or tarsi; whereas 

 the latter have their two hind feet /our-jointed, but all 

 their four front feet^ue-jointed. 



SanfordHoward. Sec. Mich. State Board Agr. — You think 

 that it is the common Army-worm, that is "said to have 

 iiaten the fall-sown wheat in sonw) of the southern coun- 

 ties of Michigan." It cannot possibly be that insect, be- 

 cause it never appears in that latitude so late in the year 

 in the larva or worn> state. In South Illinois the Army- 

 worm appears in May, in Maine in August, and at cor- 

 responding periods in intervening latitudes, always ap- 

 p.eariflg fi little later the further north you go. Are you 

 certain that it was the moth of the Army-worm, and not 

 soma other brown-looking moth, that was so numerous 

 )yith you last August? There is nothing at all improba- 

 ble in the fact, but you may possibly have been deceived. 

 Any eggs laid by the Army-worm Moth in August would 

 remain unhatched till the following season. 



We should recommend your farmers, whose corn has 

 been so utterly ruined by the "white grub," [Luchnosicr- 

 na quercina., to turn in a drove of hogs to eat them up. 

 It has been stated — we know not how truly — that mea- 

 dows where this grub abounds have been saved by run- 

 ning a very lieavy roller over them, sufficiently weighted 

 to crush the soft body of the insect, though it does not 

 injure the grass. The theory is not an improbable one, 

 but it needs to be practically tested. Let some of your 

 farmers do this and rcjiort the result to us. 



S. W. Arnold, 111.— 1st. As to the Natural History of 

 "the common horse-fly," there arc two species of about 

 the same size, one of which, with brownish eyes, is " the 

 common horse-fly "of Northern Illinois, and the other, 

 with emerald-green eyes, (whence it is popularly known 

 as the " greeuhead,") is "the common horse-fly" of Cen- 

 tral Illinois. The former is scientifically designated as 

 Tabanus lineola; the latter, we believe, as Tabanus costalis. 

 The larva of neither of them is known, but a European 

 species lives in the ground in the larva state, and Mr, 

 Walsh bred a large-sized species from a larva which he 

 ascertained to live in the water and to feed upon water- 

 snails. We copy the following from Mr. Walsh's Paper 

 en the subject in the Proceedings of the Boston Sociciy of 

 Natural History, that you may see the conclusions at 

 which he arrives : — 



"Several species of Taianus are so prodigiously abun- 

 dantin Illinois, in districts remote from any large streams 

 or ponds, that they must evidently breed in the earth like 

 DeGcer's species, not in the water like mine. There are 

 prairies in Central Illinois, as 1 am credibly informed by 

 numerous witnesses, across which it is impossible to ride 

 or drive a horse in the heat of a summer's day on account 

 of the Tabanus. » * » If, then, as appears from the 

 above considerations, the larvas of many, perhaps most, of 

 our Tabanus, live in the ground; and if, as there is every 

 reason to suppose, the larvce of the terrestrial species are 

 u carnivorous as I have shown those of the aquatic spe- 



cies to he, there can be little doubt, considering how 

 numerous in individuals many of the species are, that 

 they must destroy, during their larva life, innumerable 

 noxious subterranean larvie, J/e<o/on(At<te, Lyttidx, I'lpu- 

 lidoe, etc. They certainly cannot, at least in Illinois, feed 

 habitually upon land-snails, for land-snails are quite 

 scarce in that State. The scheme of the Creation is per- 

 fect and Nature is never at fault. It is only when IJa- 

 ture's system is but half understood, that we heedlessly 

 complain of its imperfections. We blame the house-flies 

 for annoying us, and fail to see that in the larva state they 

 have cleared away impurities around our dwellings, which 

 might otherwise have bred cholera and typhus fever. 

 We execrate the blood-thirsty mosquito, and forget that 

 in the larva state she has purified the water, which would 

 otherwise, by its malarial effluvia, have generated agues 

 and fivers. In all probability, when we rail at the Taba- 

 nus that torment our horses in the summer, we are railing 

 at insects which, in the larva state, have added millions 

 of dollars to the national wealth, by preying upon those 

 most iusiduous and unmanageable of all the insect-foes 

 of the farmer — subterraneous, root-feeding larvue." 



2nd. As to the Natural History of the Mosquito: — All 

 the male Mosquitoes and all the male Horse-flies ( raiaraiw) 

 live exclusively upon the honey and pollen of flowers, 

 and are physically incapable of drawing blood, owing to 

 the imperfect structure of their mouths. The female 

 Mosquitoes and the female Horse-flies prefer blood, if they 

 can get it; otherwise they are reduced to feediug on the 

 same substances as their less ferocious helpmates. The 

 larvce of the Mosquitoes live in stagnant water, and are 

 popularly known as " Wiggle tails." 



Before you undertake to kill off the larvie of the Horse- 

 flies and the Mosquitoes, you had best make yourself 

 quite sure that (hey are really your enemies, and not, as 

 Mr. Walsh maintains, some of your very best friends. 



Bob't S. Redfield, Philadelphia. — The best way we know 

 of killing large moths, is to puncture the under side of 

 the body, between the thorax and the abdomen, with a 

 steel pen dipped into strong muriatic acid ; this method 

 destroys immediately all muscular power, and is more 

 satisfactory than anything we have ever used. Moths 

 with very large bodies, especially females, should have 

 "the abdomen emptied of its contents and stuffed with raw 

 cotton; the operation requires some care, and the incision 

 should always be madeon the under side. With all large 

 moths it is best to insert a long pin lengthways through 

 the abdomen into the thorax, to prevent the former from 

 breaking off when dried. Call at the Hall of the Society, 

 and we shall be happy to show you how we preserve our 

 in.seets. 



Mrs. Oren G. Nevins, Wise. — It is impassible to tell from 

 your description what the supposed insects in your hot- 

 bed are. or whether they are true insects at all. Those 

 which you find on the bodies of many beetles, especially 

 dung-beetles, are not true insects, all of which have in 

 the perfect state six legs, but belong to the same class as 

 the Spiders. Mites, Ac, all of which have, throughout their 

 whole existence, eight legs, never more and never less. 

 You have very probably confounded together two entirely 

 distinct animals. Send specimens of those found at large 

 in your hot-bed, if you wish us to tell you what they are. 



We had a hearty laugh over your verses, but we insert 

 nothing in the Practic.m, Entomologist but what ia of 

 practical, everyday utility. 



M. S. Hill, East Liverpool, Ohio.— You say it will be 

 "Locust-year" with you in 1806, and you state very cor- 

 rectly that "Locust-year" varies in different localities, 

 but that, no matter when it comes, there is always, in the 

 same locality, an interval of seventeen years between one 

 "Locust-year" and that which precedes or follows it. 

 You further suggest that "it would bo interesting to have 

 a notice of the particular year in which the seventeen- 

 year locusts appear in the difl'erent parts of our country.'' 



I incline to believe, that there are certain districts in 

 the United States where this Insect is not to be found at 

 all. I lived for twelve years in Henry county, Illinois, 

 but found no "Locust-year" there. I then moved into 

 Rock Island county, 30 miles Northwest, and although I 

 have resided there fifteen years, there has been no "Lo- 

 cust-year" yet in my neighborhood. It is further observ- 

 able that on Long Island, N. Y., a few straggling indivi- 

 duals may bo met with every year. (Fitch, N. T. Rep, 

 II. i U.) 



