•114 



THE LANCASTER FARMER. 



[August, 



long ago demonstrated that wood saturated 

 with lime and other et cHeras, will continue 

 sound a much longer time than when not so 

 prepared. There are many wood-boring in- 

 sects that carry on their boring operations 

 between the bark and the wood, therefore the 

 bark should always be removed from fence 

 posts and rails. 



^ 



A SUPPLEMENT TO THE ARMY 

 WORM. 



During the advent of the "Army "Worm " 

 in the month of June last, some people who 

 professed to know all about it,alleged that we 

 had not the true Army Worm {Leumnia uni- 

 puncta) in Lancaster and Chester counties the 

 present season, and as we had stated in a pre- 

 vious paper that we had it, so far at least, as 

 Lancaster county was concerned, we said 

 nothing by way of contradicting this denial, 

 but quietly gathered worms horn various 

 localities in the county, placed them in boxes 

 containing a quantity of earth and covered 

 with cotton gauze. These had been found 

 feeding on wheat, rye, timothy and corn ; 

 and although tolerably uniform in shape, 

 lineations and other characteristic markings, 

 yet greatly variable in size and color, and 

 this variation in color had no relation what- 

 ever to the size of the worms. Some were 

 very large and light-colored, and some were 

 very small and dark-colored, but in all the 

 heads were the same, and all had the dark- 

 glazed spots on the outside of the prolegs, 

 and all were similar in their habits, feeding 

 voraciously at night, and remaining quiet or 

 hidden during the day. The largest number 

 of the light-colored worms were taken on the 

 corn along the margin of a wlieat held, where 

 they had been previously located, but the 

 wheat ripened before they were fully de- 



veloped, and then they left the wheat field 

 and attacked three or foiu' marginal rows of 

 the corn field. Those taken from the wheat 

 fields were uniformly dark-colored, and those 

 on the timothy were both dark and light- 

 colored. We incarceratetl, them from the 

 20th to the 2.5th of June, and before the 1st 

 of July all that were able had burrowed in 

 the ground. A few of them pupated and 

 produced the mahogany-colored and anally 

 spined pupce. On the 12th of July the first 

 moth appeared, and a true unipunrta. Al- 

 though the moths also vary in color, there is 

 less variation in them than there is in the 

 larva, and we mention this here because it 

 had i)een previously stated very frequently 

 that they were very imiform in color. Can 

 the plant-food have anything to do with the 

 coloration of the worm ? AVe never before 

 noticed a greater variation in tlie color of 

 worms. 



Never but once before did we notice so 

 large a proportionate number of worms in- 

 fested by parasites, except, perhaps, on a 

 single occasion. We once received from 

 Chambersburg, Pa., twenty-one or two speci- 

 mens of llie 2>i'}M of the "White Cabbage 

 Butterfly," (Fieris rap<r) and seventeen of 

 them were infested with a small Hj'menopter- 

 ous parasite, (P4cromah(sprtpa)-!(?(!,) and out 

 of- the whole number we only succeeded in 

 rearing three females and one male butterfly, 

 but we bred at least fifty of the parasite's, 

 most of which we permitted to make their 

 escape. Even so most of our army worms 

 were infested by at least two species of para- 

 sites. Some were infested by a large, white, 

 spindle-shaped maggot (only one in each) 

 which we presumed were the larvre of a 

 species of "Tachina fly." These may huve 

 proved Exoriala kucania, or Jlavicmula, of 

 Kirk and Riley, but from unfriendly sur- 

 roimding conditions we failed to develop the 



fly. But not long after the worms burrowed 

 into the ground, or even before they had all 

 accomplished tliat change we noticed scattered 

 over the swface of the earth, or adhering in 

 clusters of from three to twenty small white 

 silken cocoons, which only in one instance 

 adhered to the body of a worm. Confining 

 these little cocoons in a separate box, we 

 bred a large number of what seems to be 

 Walsh's Military Microgaster (Mlcrogaster 

 militaris.) With these and other parasites, 

 besides a number of predaceous ground- 

 beetles, birds, chickens, skunks, pigs, and un- 

 friendly meteorological;,conditions, the Army 

 AVorm, under ordinary circumstances, has not 

 a very great chance of becoming either nu- 

 merous or destructive in Lancaster county, or 

 in Pennsylvania. Indeed, we believe its 

 presence and its destructions were largely 

 overrated, even where it occurred the most 

 abundantly. AVe did not visit a single locali- 

 ty, where they were reported bad, tliat we 

 had not to hunt a considerable time before we 

 could obtain what specimens we wanted. 

 It is true, we only ^visited those locali- 

 ties during daylight ; but, judging from 

 the damage done, and the little appar- 

 ent difference in yield between the in- 

 fested and the non-infested districts, the 

 loss was very limited indeed — hardly 

 worth mentioning. 



AVe have noticed the Army AVorm in Lan- 

 caster county almost as long as we have no- 

 ticed the " Red-legged Grasshopper," {Calop- 

 terous fenier-rubriim,) and we presume the 

 possibilities of either of them becoming a 

 scourge are about equal ; but although occa- 

 sionally both have done some damage to the 

 crops, yet, it cannot be said to have amount- 

 ed to a calamity in the presence of either. 

 The exact periods and number of their broods 

 cannot be regarded as clearly defined. Among 

 the worms observed about the middle of 

 June, were some fully developed, and some 

 not more than half an inch long, and the 

 difference between the periods of their ma- 

 turity could not have been less than a week 

 or more. The earliest of the moths we no- 

 ticed must have evolved between the 10th 

 and 12th of July. Of course, it cannot be 

 presumed that moths bred so early would sur- 

 vive through the warm, growing months of 

 July, August, September and October, and 

 then hybernate all winter in the moth state, 

 and only deposit their eggs next spring. AVe 

 have found a few straggling Army AVorms as 

 late as August and September, and these we 

 presumed to bea\second brood. The first 

 brood doubtless deposit their eggs on the 

 grass or grain in the vicinity of their place of 

 evolution, but having ample wings to fly 

 with, there would be nothing to prevent them 

 from seeking a new locality if their natal one 

 was unfavorable to their perpetuation, AVe 

 have seen moths and butterflies, too, flitting 

 aljout on exceeding warm days in midwinter, 

 and we have had them evolve from the pupa 

 in the house under similar circumstances, but 

 this affords us no reason to infer that they 

 had been previously hibernating in the moth 

 state, any more in the one case than in the 

 other, ^ome two or three years ago a speci- 

 men of Pieris rapcf- flew into an open window 

 of the Intelliqciirer printing office, in Lancas- 

 ter city, on the 20th of February, while the 

 ground was covered with snow. But the day 

 was very warm, and doubtless the pupa was 

 exposed to the sun's concentrated rays, and 

 was prematurely stimulated to evolution. 



Frequently an unusual number of common 

 flies may be noticed when there is a succes- 

 sion of two or three very warm days in mid- 

 winter. AVhen a sudden change to a low 

 temperature occurs, the flies will likely also 

 as suddenly disappear, only to reappear a 

 week or ten days hence when the warm tem- 

 perature returns. Although these flies may 

 hibernate during the cold interval, yet it does 

 not follow as a matter of course. AVhen the 

 cold winter weather commences it may over- 

 take flies and other insects in various stages 

 of development — eggs, immature- and mature 

 larvce, and diflereutiated jjitpce. These, like 



the buds of a tree in their expansion, are 

 ready for development as soon as the sur- 

 rounding cir- 

 c u m s tances 

 become fa- 

 vorable to 

 their growth. 

 It is the 

 same with 

 - ,, , . . m a u y 1 n- 



*& " sects; amag- 



'^^ got or grub 



may be transformed to a pupa, and a pupa 

 may evolve a fly, a moth or a butterfly ; and 

 there is, therefore, no necessity in presuming 

 that the insect may have been liiberuating in 

 the imago state during the long and varied 

 winter season. We have frequently found 

 caterpillars feeding under cover of shelter 

 during warm winter days, and this has been 

 repeated as often as these alternations of 

 temperature occurred, without injury to the 

 insects, provided they were not too frequently 

 saturated and subjected to alternate freezing 

 and thawing. Army AVorms and cut worms 

 are subject to the same contigencies. We 

 have seen Army Worms (both unipimcta and 

 aJhilinea), immature and maiure, after the 

 25th of September, and common cut worms 

 every month in the year. Our theory, there- 

 fore, is that none of either the larvse, the 

 pupai or the imago of the first brood of the 

 Army AVorm ever survive the winter follow- 

 ing their advent ; and through the contin- 

 gencies above enumerated, it very seldom 

 occurs that there is much of a second brood, 

 and in this latitude no third brood at all, al- 

 though there may occasionally be such an 

 appearance. It is, therefore, the second 

 brood, possibly as a larrcK, probably as a 

 2nqM, and perhaps as a belated gravid female 

 that bridges the race over a supervening win- 

 ter. It frequently occurs that the moths of 

 species allied to the Army Worm moth are 

 found imbibing the neter of wild flowers as 

 late as the month of November. These, in 

 some cases, may survive the winter and ovi- 

 posit in the spring, and if they are so found, 

 faded and mutilated, it is likely they have 

 survived by hibernation. 



Briefly, then, we have a greater or less 

 number of Army Worms with us every sea- 

 son, scattered over the spring, summer and 

 autumn months, and hence the possibilities of 

 a redundancy of them always exists. But at 

 the same time there is no insect subject to 

 more fatal contingencies, more easily accessi- 

 ble, or that yields more readily to simple 

 remedies for its destruction or prevention, if 

 only oidinary vigilance is observed. Al- 

 though possible, we do not think it very 

 pi'obable that there ever will be two Army 

 Worm seasons in succession of equal malig- 

 nancy. Still, to be on the safe side, we would 

 not advise the relaxation of any means neces- 

 sary to guard against their destructive multi- 

 plicity. Eggs will no doubt be deposited 

 from early spring until late autumn, and 

 these eggs are as liable to be destroyed by 

 parasitic infestation and other contingencies, 

 as either the worm itself, its pupa, or its 

 moth is, so that very probably all the worms 

 of next year will be hatched from eggs depos- 

 ited next spring by gravid females that have 

 survived the winter in a state of hibernation, 

 or from females which have evolved from 

 pupae that have passed the winter in the earth 

 in a state of hibernation, (if not from eggs 

 deposited late in summer or early fall) possi- 

 bly more of the latter than of the former. 

 Gravid female insects, in many cases, possess 

 an immense amount of tenacious vitality, 

 until their eggs have been deposited, after 

 which they soon die from physical exhaustion. 

 So, also, males will often survive for an al- 

 most indefinite period, if they have had no 

 opportunity to fertilize a female, but after 

 that event, in most instances, their physical 

 energies are soon exhausted. Indeed, in 

 some species the alimentary organs of the 

 males are merely rudimental or obsolete, and 

 tlieir sole function in the imago state, is the 

 fertilization of the females ; and many seem 



