318 



SCIUJS'CE. 



[Vol. IX., No. 21T 



best definition of value or worth, and that it should 

 be adopted as the .s;cientific meaning of the term. 



At any rate, a discussion on this topic is most 

 timely. The basic idea of the modern labor move 

 ment is the idea that workingmen do not get an 

 equivalent (equal value) for what they produce. If 

 scientific men are to take any hand in practical poli- 

 tics or applied sociology, this is the point where their 

 work is most required at present. 



E. Langerfeld. 

 New York, March 26. 



The destructive caterpillars of the squares of 

 New York. 



Since the importation into America of the quarrel- 

 some, active, and noisy English sparrows, which 

 have driven the quiet and brilliant birds of the 

 south from the city gardens and parks, a new pro- 

 lific horde, with fierce appetites, every year more 

 extended, threatens to destroy oiir fresh and green 

 shade-trees. 



As early as 1882 the New York evening telegram 

 sounded a note of alarm on this snbject, to which we 

 added another, but without effect. When nature 

 threw off its summer mantle, and this ravaging army 

 quietly took up its winter quarters, every thing 

 seemed to be forgotten, and our modest communica- 

 tion no doubt went into the pigeon-hole of oblivion ; 

 nevertheless, we try again. 



After three years' study of the devastating habits 

 of caterpillars, we tried to engage the attention of 

 the committees having charge of the city parks; but 

 to no purpose, for in the summer of 1883 the enemy 

 had greatly multiplied. After some years of neglect, 

 it was too late to save from destruction the plants 

 which had become insufficient to feed the successive 

 broods of myriads of caterpillars. The new-comers 

 soon got beyond the city limits ; and once getting a 

 foothold in the suburbs, science, the fruit of obser- 

 vation, could no longer keep within bounds the vo- 

 racity of these unattackable hairy pests. 



The damage of one year may be unlike that of the 

 preceding or following; atmospheric changes may 

 destroy multitudes ; but the enemy is prolific, and 

 will in a year increase ten, a hundred fold, and even 

 more. 



As the press of New York and even intelligent citi- 

 zens may think that this enemy has disappeared, we 

 raise a new cry of alarm, addressing ourselves to the 

 learned societies of our adopted country, at the same 

 time communicating the results of our studies to in- 

 telligent readers interested in the natural sciences. 

 Our statements will be based on facts observed by 

 us in New York, supported by the testimony of 

 learned colleagues with whom Ave (myself and son) 

 have corresponded for more than two years, during 

 which we have studied the increasing ravages of 

 this coquette with brilliant, silky, and variegated 

 dress which science names the Orgyia caterpillar. 



When the European sparrow was first introduced 

 into the parks of New York, a caterpillar was there 

 committing great depredations. Linnaeus called it 

 the geometer : we call it looper, spanner, and can- 

 ker-worm. The larva has «ix feet on the first three 

 segments, and four on the last two, and as it pro- 

 gresses seems to measure the ground. The sparrows 

 were very fond of this caterpillar, to a degree that 

 their increasing numbers speedily exterminated it : 

 for this they deserve our gratitude. It was different 



with the larvae of the Orgyia. Conseqiiently we have 

 thought it might be of interest to the public to say a. 

 little of what is known of the habits of the first 

 as compared with the second equally destructive 

 species. The first still exists in many private gar- 

 dens in New York 



Phalaenidae. — The butterflies which come from 

 the larvae of the geometers almost all have the body 

 slender, the thorax narrow, and wings proportionally 

 wide ; their flight being consequently more uneven 

 and jerky, more unsteady, than that of the nocturnal 

 species : the flight, in fact, is more like that of the 

 diurnal ones, but is neither so strong nor of long 

 duration, on account of the comparative weakness of 

 the framework of the wings. They especially like 

 serene and still evenings and nights. But there are 

 to this characterization many excej^tions. Some of 

 the Phalaenian larvae have 12 legs, and some evert 

 14 ; among the nocturnal species, again, some have 

 12 and others 14 legs; the general rule being 16 

 legs among the nocturnal, and 10 among Phalaenians. 

 It is also a curious fact that the larvae of those with 

 16 legs loop in pi'Ogressing, for some reason making 

 no use of the intermediate legs. 



Another kind of exception is that some Phalaenians 

 which are nocturnal, a small number it is true, have 

 a diurnal flight ; that is to say, that certain species 

 fly in full sunlight, gathering food on flowers in 

 company with diurnal butterflies : so that the divis- 

 ion into diurnal and nocturnal species is, in this re- 

 spect, conventional. It is, however, true that day 

 butterflies have almost always the antennae club- 

 shaped, and come from larvae with 16 legs ; while 

 the Phalaenians, whose larvae have 10, 12, or 14 

 legs, have filiform or pectinated antennae. 



There are in Europe some 600 Phalaenians, 700 

 nocturnal, and 400 diurnal butterfiies ; though it is 

 probable that in hot climates the diurnal are more 

 nixmerous than in the' temperate. The Phalaenians, 

 especially in cold regions, have usually sombre 

 colors, gray or black, though there are many excep- 

 tions. In Prance there is a large and handsome 

 green species, which is a common symbol on the 

 tombs of children, probably on account of its deli- 

 cate form and color. They hatch at all seasons of 

 the year : there is even a group (Hyberniadae) 

 which appears in December, January, and Pebruary. 

 The Phalaenians may emerge from the pupa even 

 below 50" P., while "the others, and especially the 

 diurnal species, require at least this temperature. 



In Hibernia we find a singular fact. The females 

 have either no wings, or semi-wings unfit for flight. 

 As the pupa is generally in the earth, the female, on 

 emerging, crawls up the nearest tree, where pairing 

 takes place ; the male bearing her to the top of the 

 tree, and sometimes carrying her off in his flight. 

 The females are small ; and the males, much larger, 

 deposit them in places proper for the svipport of the 

 larvae, — buds of flowers, or masses of leaves, accord- 

 ing to the sjDecies. There are in this group some 

 veritable pests for man. The H. de foliaerio some- 

 times so destroys the leaves of forest-trees, that, un- 

 able to respire, thej' either die or partially wither. 

 The H. brumata consumes every thing in the 

 orchards, attacking the flowers of all kinds of fruit- 

 trees. 



It would be interesting, but impossible here, to 

 speak of the habits of many of these butterflies, and 

 to note their exceptional characters ; but a single 

 example must suffice. There is among the Phalae- 



