8 



THE "LANCASTER FARMER. 



[January I 



insect friends, and conspicuously amongst 

 them are tlie Dragon-flies. These insects are 

 very perfect in their flight, and usually cap- 

 ture their prey "on the wing— butterflies, 

 day-flying moths, grasshoppers, etc., being 

 their victims. Their larvaj inliabit the water, 

 and are voracious feeders on small water 

 insects. The Hemerobimis or Lace-wings, 

 are vigilant Aphis destroyers, while they are 

 in the larva state. The Perlans and Panor- 

 pans of this order are also predaceous, espe- 

 cially in the larva state — inhabiting the water. 

 In a limited paper on this subject, it would 

 be impossible to enumerate many of our 

 insect friends, or even to describe the few we 

 have cited by way of illustration. Their 

 name is " legion " — enough at all events to 

 preserve an equilibrio, if it were not that the 

 destructive species seem to be more prolific 

 than our friends ; t\ie effect perhaps of im- 

 proved cultivation— we have improved the 

 plant food — they appreciate it and thrive. 

 We must balance this by fostering our friends. 

 But, far outnumbering all the foregoing, 

 both in genera and species, are the great 

 families of insect friends usually denominated 

 parasites. Many of these are solitary in their 

 habits, but perhaps as great a number are 

 gregarious. It would perhaps be quite safe 

 to assert that every single species has an in- 

 sect parasite that prays upon it, and it is 

 quite certain that even the parasites have 

 other and smaller parasites that prey on 

 them. Few of these parasites have received 

 common, or English names, and to give their 

 Latin names would only complicate the sub- 

 ject, and leave the common reader little the 

 wiser. These parasites are in no wise vege- 

 table feeders, nor do they feed on tainted or 

 putrid flesh. The larva, the jnipa or the 

 imago of a living insect is their chosen prey, 

 and their offspring feed alone on that kind of 

 food. As soon as they emerge from their 

 own pupal condition, they are brisk, active, 

 and intelligent, and know exactly what to do 

 and how to do it. Sometimes the most 

 casual observer recognizes the presence of 

 some species of these parasites, although he 

 or she may be entirely ignorant of what they 

 are, or their modes of operation. Perhaps 

 the most familiar example of the good works 

 of these little parasites, is the development of 

 those that infest tlie common green " Horn- 

 worm of the tobacco plant, and the tomato 

 and potato vines. As an illustration of the 

 possibilities of the parasites that infest this 

 worm, I have only to mention that in the 

 month of August last I bred over three 

 hundred of these parasites {3Iicro</aster con- 

 gregata) from one horn-worm. Whether the 

 eggs that produced these parasites were all 

 deposited by one female is more than I am 

 able to affirm, but probably they were. This 

 parasite is in the form of a very small fly — 

 hardly as large as a mosquito — with four 

 rounded " clear- wings,'' with a dark body, 

 sometimes tinged with green or blue. The 

 little parasite, after its evolution from the 

 pupa state, as a perfect tly, seeks a naked 

 caterpillar of some kind — for they do not 

 confine themselves to the " Horn-worm alone ; 

 the large grape-worms are also infested by 

 them, and also many other smaller naked 

 species. Having found its host it very adroitly 

 but deliberately proceeds to deposit its eggs 



in or on the body of the worm, and these 

 eggs when hatched exclude a minute whitish 

 worm which burrows into the body of said 

 caterpillar and feeds on its substance, but 

 touches no vital part. Perhaps the horn- 

 worm would survive the attack if there were 

 only a very small number of the parasites 

 present, but they usually number from fifty 

 to three hundred or more, and the physical 

 depletion caused by these usually destroys the 

 horn-worm, at least none that came under 

 my observation ever sm'vived. 



When these parasites have completed their 

 larvie development, they issue from the body 

 of their host, and each one spins a separate 

 cocoon about the size of a grain of rice, and 

 attached by one end to the skin of the horn; 

 or other worm. In these little cocoons they 

 pass their pupal period, at the end of which 

 each occupant of a cocoon cuts squarely off' 

 the upper end aud emerges forth a perfect 

 four-winged fly, in all respects like the parent 

 that deposited the eggs. There is nothing 

 spasmodic, nothing contingent or inconstant 

 in the characteristics of these little parasites ; 

 they have been going through this develop- 

 mental process ever since their first advent 

 into the material world, aud they will con- 

 tinue in it from generation to generation as 

 long as the conditions necessary to their 

 development endure. There is no poisonous 

 application, no artificial remedy, no human 

 device or invention that can possibly super- 

 sede this balancing provision in the economy 

 of nature. The history of this one species, 

 under various modifications is the history of 

 hundreds or thousands of others belonging to 

 the parasitic tribes. Night and day during 

 the whole summer season these little friends 

 are working in the interest of the human 

 family by restricting the multiplication of 

 noxious insects. Then again, there is a vast 

 family of solitary parasites, known under the 

 names of "Cuckoo-flies," " Ichneumon -flies," 

 "Chalcies-flies," &c., some of which, how- 

 ever are not strictly solitary. These never 

 construct a nest or cell for themselves, but 

 prowl about watching those who do engage 

 in these provident labors, aud cucoo-like as 

 soon as they find the proprietors absent, they 

 stealthily deposit an egg or more in each cell 

 and when the young grub is hatched out, it 

 very deliberately appropriates the larva of the 

 original proprietor. Some of these parasites 

 are as large as the common wasp and are pro- 

 vided with a long ovipositor, by means of 

 which they are enabled to reach the bodies of 

 wood-worms, several inches from the surfiice. 

 Into which they deposit one or more eggs, and 

 by that means arrest their progress in the de- 

 struction of trees and timbers. The white 

 ''Cabbage-butterfly," aud the black "swal- 

 low-tail," are very liable to parasitic infesta- 

 tion. The latter has a parasite as large as the 

 common wasp, and the entomological novice 

 has often been confused in finding a Trocjus 

 fulvtis in his breeding cage, instead of a Pa})- 

 ilis asterias, bred from the black, yellow and 

 green-worms which feeds upon umbelliferous 

 plants. The little Ptcroiaahis puparitm will 

 eventually curtail or destroy the greeu-cal> 

 bage-worms, more effectually thau any artifi- 

 cial remedy. On one occasion I had chrysalids 

 of the latter insect sent to me, and out of a 

 score of them I only was able to get three but- 



terflies ; the other seventeen evolved about 

 fifty of the little "chalcis-flies," named. It 

 only needs the diffusion of this fly as exten- 

 sively as its host to totally exterminate the 

 latter. 



The "Fossorial Wasps" or "Mason Wasps," 

 constitute another family of insect friends. 

 These make deep burrows in the ground, 

 which are divided oft' into a number of cells. 

 Then the parent wasp— usually the provident 

 mother — captures a naked caterpillar or cut- 

 worm, paralyzes it, and crams it into her cell. 

 She then deposits an egg on it and closes the 

 cell, aud when the young grub is excluded 

 from the egg it commences to feast on the 

 caterpillar, and when the last of it is con- 

 sumed the grub is mature and is transformed 

 to a piqxi, and in due time comes forth a per- 

 fect wasp, endowed with all the instincts and 

 abilities to " go aud do likewise." 



Of course, some insects are enemies, in one 

 sense, to the human family, particularly when 

 they occur in great numbers : but even these 

 have been known to confer a benefit by their 

 fruit-pruning, twig-pruning and leaf-pruning, 

 and when, through vigorous cultivation fruit- 

 trees can be brought to yield crops as they are 

 said once to have yielded — that is, enough for 

 the human family (provided that family ever 

 discovers when it has enough) aud the insects 

 also— their usefulness as pruners may be rec- 

 ognized and even desired. Bui for every 

 single species that any suff'erer can point out 

 as really destructive to vegetation or to any 

 other human interest, any intelligent ento- 

 mologist could point out a species that is abso- 

 lutely and unqualifiedly a friend to human 

 interests. Nearly the whole question impinges 

 upon their redundancy, ignorance of their 

 development, and how to utilize them. Sup- 

 pose the uses of silk had never been discov- 

 ered 'i' Can any one doubt that a war of ex- 

 termination would have been waged against 

 the silkworm where it was a native, as one of 

 the greatest defoliators in the class to wliich it 

 belongs ? 



But not alone by their overt and covert 

 actions are insects the friends of humanity — 

 not alone by their direct and indirect manipu- 

 lations, but also incidentally, and without 

 design on their part at all. It is not only 

 ascertained that insects assist the fertilization 

 of a vast number of trees, shrubs and plants, 

 but it is also pretty certain that some plants 

 could not become fertilized at all, if it were 

 not for the intervention^ of insects. These 

 beneficial works — parallel with their injurious 

 works, perhaps— are constantly going on 

 throughout the entire realm of nature, wher- 

 ever and whenever there is suflicient warmth 

 ind moisture to vitalize them; and when their 

 labors cease, it is only because the necessary 

 conditions have ceased to exist. 



Now, the o'oject of this essay is not to illus- 

 trate that insects, without qualification, are 

 the friends of the human family, and there- 

 fore that it is useless to attempt to subordi- 

 nate them to human interests. Even admit- 

 ting that they are friends per se, we may still 

 have occasion to pray for a "deliverance from 

 our friends," as earnestly as such an invoca- 

 tion is often made in the domestic, the social, 

 and the political world. It is, perhaps, most 

 eminently a question founded upon use and 

 abuse. Save the atmosphere that a human 



