'•'■^ * !^^ ■1.1 '^i^jt'^jl. ;^^i^ I?**.- 'sri,. -, f ^i ^:'i^M^:ii^^^^r^0^^ff^' ^ ^ ^ THE UB'IARY OF E^Tt RTA1N>JSG KNOWLEDGE. IJVSECT TRANSFORMATIONS BOSTON: LILLY & WAIT, {late WELLS ^ LILLY,) C. 4- C. (V H. Carvill, and E. Bliss, New-York; Carey (V Hart, Philadel- phia ; W. if J. iNeal, and E. J. Coale, Baltimore ; P. Thompson if Ho- maiis, Washington ; R. Cruikshank, Georgetown ; W. M. Morrison, Alexandria; K. D. Sanxay, Richmond; C. P. M'Kennie, Charlottes- ville; W. H. Berrett, Charleston, S. C; Salmon Hall, Newbern, N.C. ; Mary Carroll, New-Oileans ; Odiorne & Smith, Mobile ; J. P. Ayres, Nashville, T. ; A. 4- G Guilford, Cincinnati ; Little if Cummings, Al- bany; H. Howe, New Haven; H. if F. J. Huntington, Hartford; S.But- ler & Son, Northampton ; Whipple if Lawrence, Salem; Eli French, Dover; H. S, Favor, Eastport; and S. Colman, Portland. 1S31. ^S^^^'^tjjiAv >#Hlia!yV^^*^ /3Z-? ^^ CONTENTS SECTION I. — EGGS OF INSECTS. CHAPTER I. — Introductory. Page All insects come from eggs, 1 Curious experiment of Kircher, 2 Virgil's receipt for making a swarm of bees, 3 Origin of these ancient errors, 4 Bees in Sampson's lion accounted for, 7 Fancies of Robinet and Darwin, 9 Theory of spontaneous generation, 10 Popular errors respecting blight, 11 Dr Good's account of blight, 12 No insect eggs afloat in the air, 1* Specific gravity of insect eggs, 15 Theoretical accounts of honey-dew, 16 Accounted for by experiments, 18 Instantaneous appearance of insects, 19 The ' worm i' the bud' traced to its egg, 20 Insectiferous winds, 22 Supposed shower of frogs, snails, &c, 23 Diffusion of the seeds of plants, 2+ Insects jet out their eggs from fear, 25 Origin of mosses on walls, 27 Origin of mould in the heart of an apple, SO CHAPTER II. Physiology of insects" eggs, 33 Theory of colours meant for concealment, »b. Disproved in the case of the eggs of birds, 34 Illustrated from insect eggs, 35 Cause of the colours hi eggs, 36 Structure of insects' eggs, 38 Eggs of ants, spiders, and glow-worms, 39 Form nf insect eggs, 40 Cause of the oval form in birds' eggs, 41 Sculpture of the eggs of insects, ib. Curious appendages to eggs, 43 Eggs with foot stalks, 45 Number of insect eggs, and their fecundity, compared with other animals, 46 CHAPTER III. Maternal care of insects respecting their eggs, 49 Instanced in a carpenter bee (Chelosioma), 50 Ichneumons compared to tlie cuckoo, 52 Proceedings nf a solitary bee (Halictus), 53 Stratagems of a solitary wasp (Cercerit), 54 IT CONTENTS. page Ovipositor of an ichneumon (Pimpla), ■)*j Experiments of Reaumur, 57 Common mistakes of Naturalists, 69 Parasite of the cabbage caterpillar (Pon/ja), 61 Egg parasites, 63 Parasites of the aphides, 65 Singular parasite of the cock-roach, 66 Rare parasites of bees and wasps, 67 Tact of infects in discovering food for their young, 68 Sometimes select exotic plants, 69 Instanced in a leaf-miner {Tcphrilis?), 70 Solitary and gregarious caterpillars, 71 Life-boat of eggs constructed by the gnat, 72 Experiments upon it, 75 Infallibility (if instinct questioned, 76 Mistakes of instinct, 77 CHAPTER IV. Hybernation of insects' eggs, 79 Proceedings of the gypsey moth compared to the eider duck, ib. Singular groups of eggs, 81 Protection of eggs from heat, 83 Anal tweezers of moths, 84 Eggs in spiral groups, 85 Arched form of the lackey moth's eggs, 80 Hybernation of the eggs of aphides, 87 Singular protection of the eggs of cocci, 88 Coccus of the hawthorn, 90 Shell-formed coccus of the currant, 92 Hybernation of spiders' eggs, 93 Curious spider's nests, 9i Eggs of tlie vapourer moth on its cocoon, 9.> Effects of cold on insects' eggs, 96 Observations of John Hunter, 98 Insects not killed by severe frosts, ib. CHAPTER V. Hatching of insect eggs, 100 Structure of the eggs of birds, ib. Insects do not hatch their eggs, 101 Anomalous instance of the earwig, 1C2 Earwigs cannot get into the brain, 103 Partial hatching by spiders, 1(J4 Experiments upon the wolf spider by Swammerdam and Bonnet, 105 Eggs hatched before they are laid, 108 Ovo-viviparous insects, 109 Coil of larvae in the body of a blow-fly, 110 Aphides sometimes produce eggs, sometimes young, 11* CONTENTS. V rage Care taken of these eggs by ants, 1 13 Cocco-viviparous flies \Hippoboscid(E), 116 Effects of heat upon eggs, 118 Management of silk- worms' eggs, 120 Eft'ects of light on eggs, ib. Some insect eggs increase in size, 121 Growth of the eggs of ants, 122 Developement of the eggs of spiders, 123 Spiders live long without food, 124 Insects probably gnaw through their egg-shells, 125 Valves of insect eggs, 126 Period of hatching influenced by temperature, 127 SECTION II.— L.\RV^. CHAPTER VI. Structure of caterpillars, grubs, and maggots, 128 Meanings of these terms, Note, ib. Supposed transmutation of plants into animals, 129 Observations of Unger upon this, 130 Remarks of Bory St Vincent, 131 Supposed formative power of the blood, 132 Embryo butterfly in the caterpillar, 133 Experiments to show this, . 134 Dissections of the buds of plants, 136 Difference of plants from insects, 137 Internal structure of caterpillars, 138 Breathing-tubes and formation of their blood, 139 Colours of caterpillars not intended for concealment, 140 Imitative forms of caterpillars, 142 Walking-leaf insect, 144 Caterpillars in form of branches, 145 Conspicuously coloured caterpillars, 147 Butterflies supposed to be coloured like flowers, 149 Singular forms of caterpillars, 151 Forms of water-grubs, 154 Breathing organs in water larvse, 156 Water worms (JVaw) may be mistaken for larvae, 159 Syringe for respiration in a water larva, 161 Curious mask of the same larva, 163 Dust mask of the wolf bug (Reduvius), 165 CHAPTER VII. Growth, moulting, strength, defence, and hybernation of larvze, 166 Progressive increase of the silk-worm, 167 Compared with tiie growth of buds, 168 Process of moulting or casting the skin, 169 Accidents interrupt this process, 170 Reds, a disorder similar to renal gravel, 172 Position of the hairs in moulting, 173 VOL. VI. tt VI CONTENTS. Fage Casting of the interior lining of the stomach, &c, 174 Moulting of birds, 176 Cast skins sometimes devoured, 177 Mis-statement of Goldsmith, ib. Contrivances for escape from confinement, 178 Muscular strengtli of insects, 179 Fleas made to draw miniature coaches, 180 Numerous muscles of the cossus, 182 Its wonderful strength, 184 Mis-statements respecting the strength of insects, 185 Means of escape by spinning, 186 Defensive hairs and spines of caterpillars, 187 Excrementitious covering of some larvse, 190 Origin of the froth on plants called cuckoo-spit, 191 Winter covering of caterpillars, 192 Fat a probable defence against cold, 195 CHAPTER VIII. Voracity of caterpillars, grubs, and maggots, 196 Increase of weight in the silk-worm in thirtj' days, 197 Remarkable change in the capacity of the stomach, 198 Instances of hunian voracity, 201 Jaws or mandibles of larva"., 202 Caterpillars, ib. Blight caused by an oak-leaf-roller, 203 Ravages of the buff-tip, 204 Encamping caterpillars of the ermine moths, 205 Exiieriments with these, 206 Extraordinary ravages of the brown-tail moth, 208 Strange enactment of the Parliament of Paris, 209 Cause of the abundance of caterpillars in particular years, 210 Alarm caused in France by the gamma moth, 211 Calculation of their fecundity, 212 Cabbage caterpillars prefer weeds, 213 Disappearance of the black-veined white butterfly, 214 Ravages of the caterpillar of the gooseberry saw-fly, 215 Similar ravages committed on other trees, 216 Slug worm of North America, 217 Turnip fly erroneously fancied to come across the sea to Norfolk, 218 Effects of ^gerisB on currant and poplar trees, 220 Destruction of grain by Euplocami and Tinae, 221 Bee-hives injured by Gallarife, 222 Caterpillar which feeds on chocolate, 224 CHAPTER IX. Voracity of grubs, 225 Grub of the cockchafer or may-bug, 226 Account of its transformation, &c, 227 CONTENTS. VII Page Methods of destroying, 2z8 Wire worm the grub of Hemirhipus, 229 Probable mistake respecting the destruction of wheat, 231 Pea beetle of North America, 233 Corn weevil, 234 Mealworm, the grub of Tenebrio molitor, ib. Tabby moth caterpillar devours butter and fat, 236 Intestinal worms, ib. Mistakes of Linnaeus, Dr Barry, and Dr J. P. Frank, 237 Experiment of M. Deslonchamps, 238 Extraordinary case of Mary Riordan, by Dr Pickells, 239 Authenticity of this case proved, 241 Fruit grubs, 242 JVut weevil and its transformations, ib. Apple-bud weevil, 243 Voracity nfCalosoma, 244 Rayed galleries of a bark-grub, 245 Ravages of locusts, 246 Their swarms in Southern Africa, 247 The Italian locust, 249 Migrations in Palestine and Europe, 250 CHAPTER X. Voracity of maggots, 252 Maggots of crane flies popularly called the grub, ib. Remarkable ovipositor, 253 Destruction of herbage on Blackheath, 254 Similar devastations in Poitou and Holderness, 255 Wheat fly, described by i\Ir ShireflT, 256 Additional particulars by Mr Gorrie, 259 Observations ofKirby, 260 Mistake of Mr Markwick, 261 Hessian fly, as described by Mr Say, 262 Cheese-hopper the maggot ofPiophila, 263 Wonderful structure of this maggot, 264 Its transformation into a fly, 265 Origin of the house fly (Musca domtslica), 266 Mistakes of Ray and Reaumur, 267 Voracit}' of the maggots of blow-flies, 268 Instance of man devoured by them, j(3_ Popular mistake respecting lariy-birds, 269 Their transformations traced to the egg, o^q Aphides checked by these and by SyrphidDe, SECTION III. — PUP^. CHAPTER XI. Mechanism of suspending chrysalides, 272 Proceedings of larvae upon their approaching change, 273 In what manner some caterpillars suspend themselves, 274 CONTENTS. Their attempts sometimes unsuccessful, 277 Organ for holding fast, 278 Suspensory cincture of other caterpillars, 279 Method of forming this by the swallow-tail, 28( Parchment-like pupa case of flies (Muscidm), 282 Flaslc-shaped pupse of Syrphidae, 284 Transformations of a Tipulidan gnat, 285 Mode by which the nymph is suspended, 286 Hooked aquatic pupa {Hydroca:upa?), 287 CHAPTER XH. Form and structure of pupae, 288 The term of Metamorphosis objected to, ib. Harvey's fancies about transmutation, 289 Similar fancies of Goedart exposed by Swammerdam, 290 Structure of the pupa of the chameleon fly, 292 Pupa of the lappit moth, 293 Chrysalis and transformations of the peacock butterfly, 294 Origin of philosophic errors, 296 Changes produced on pupae by evaporation, 297 Objections to the theory of evaporation, 293 Respiratory organs of pupre, 300 Experiments upon the breathing of pupae, 301 Valves of the spiracles, 302 Breatliing apparatus in the pupae of aquatic crane flies and gnats, 304 Plumed apparatus of the blood-worm, 305 CHAPTER Xni. Transformation of pupai into perfect insects, 307 Theory of transpiration by means of heat, ib. Objections to this theory, 308 Experiments by Reaumirr, 309 Chrysalides hatched under a hen, 310 Forcing of butterflies in winter, 311 Retarding the evolution of butterflies by cold, 312 Experiments on pupae led to tlie varnishing "f eggs, ib. Illustraticms of torpidity in animals and plants, 313 Various periods of disclosure in the same brood, 314 Supposed final cause of this, 315 Fixed time of the day for some insects to be evolved, 316 Remarkable evolution of the gnat, 317 Still more remarkable instance of the blond-worm, 319 Netted doors in the pupa cases of caddis-flies, 320 Bellows-apparatus in the pupa of the blow-fly, 321 Contrivance in the pupae of wood feeders, 322 Singularity in the locust moth, 323 Ingenious contrivance in a small leaf roller, 324 CONTENTS. IX Page Mistake of Bonnet with respect to the teazle-moth, 325 Pupa cases opened by extraneous assistance, 326 Observations on this by the younger Iluber, 327 Experiment by Dr J. R. Johnson, 329 De Geer's observations contrary to those of Swam- merfiam, 330 Remari^able circumstance in the hive bee, 331 SECTION IV. PERFECT INSECTS. CHAPTER XIV. Expansion of the body and wings in insects newly trans- formed, 333 Structure of birds to contain air, ib. Expansion in the fly of the ant-lion, 334 The mandibles prove it carnivorous, 335 Transformations of dragon-flies, 336 Folded wings of some two winged flies, 333 Malpighi's account of the transformations of the silk- worm, 339 Impulsion of fluids into the wings, 341 Kirby's account of the expansion of the swallow-tailed butterfly, 342 Swammerdam's account of the wings of the bee, 343 Air-tubes in insects' wings, 344 Nervures in the wings of plumed moths, 345 Perfect insects do not increase in size, 347 Imperfect insects from fallen chrysalides, 349 Discharges from newly-evolved insects, 330 Supposed showers of blood accounted for, 351 Theories devised to account for crimson-snow, 352 Curious fact explaining this, by Mr T. Nicholson, 354 Does not explain the red snow of the Alps, 355 CHAPTER XV. Peculiar motions of insects, 356 Motion indispensable to life, ib. Anecdote of a water-measurer, 357 Mode of combing themselves used by spiders, 358 Oscillatory motions of some tipulidse, 359 Vibratory motions of syrphi on the wing, 360 Similar motions of hawks, red-breast, &c, 361 Experiment on Scioplera vlbrans, 362 Illustrated by the wag-tail, &c, 363 (Jnat dances in winter, j5^ Opinion of Wordsworth and others, 364 Similar aerial dances of rooks, ill. Night-gambols of CorethrcE ? on a book, 363 Circular movements of a sumn-.er fly, 366 Sportive movements not necessarily social, 367 Account of the whirlwig, by Kirby and by Knapp, 368 VOL. VI. B* X CONTENTS. Page Remarkable structure of its eyes, 370 Battles of butterflies, 371 Choral assemblies of ephemeridae, 873 Account of these by Reaumur, ib. Sports of ants, ' 376 Gymnastics of ants, according to Huber, 377 CHAPTER XVr. Peculiar locomotions of insects, 379 Examples from quadrupeds, ib. Singular movements of some plant-bugs, 380 Sailing of the whirhvig beetle, 381 Walking on water by spiders, &c, 382 Walking through water by aquatic mites, 383 Oblique pace of midges, 384 Insect with its legs on its back, 385 Rapid galloping of the strawberry mite, 386 Slow movements of the oil-beetles, 387 Supposed sponges in the foot of the fly, 388 Correct notions of Derham and White, proved by Sir E, Home, 389 Apparatus in the feet of flies, 390 Leaping muscles of the flea, 39£ Leaping of grasshoppers and Springtails, 393 Springing of spiders on their prey, 394 Flight of insects, 395 Mechanism of insects' wings and their muscles, ac- cording to M. Chabrier, 396 Flying of spiders without wings, 397 CHAPTER XVII. Rest of insects, 399 Night insects rest in the day, ib. Day movements of other insects, 400 Insects have no brain nor spinal cord, ib. Want also a proper heart as well as blood, 401 Supposed pulse in insects, ib. No circulation, 402 Alleged discovery of an insect circulation, by Dr Carus, ib. How the circulation is affected in the sleep of man, 404 The same effects cannot take place in insects, 405 Sleep of senses not equally profound, 406 Torpidity of insects in winter, ib. Hybernation of ants, ■* 407 Anecdotes from Huber, 408 Hybernation of bees, 410 Discrepancies of opinion among naturalists 413 Hybernation of the hearth cricket, 414 ILLUSTRATI ON S Page 1. Comparative figures of a bee and a syrphus, 4 2. Cell of a queen of the Termites bellicosi, broken open in front; the labourers surrounding the queen, and carrying oti" the eggs, 15 3. Groups of eggs of the rose-leaf roller on a pane of glass, 20 4. Plants of spharobulus, natural size, 26 5. Ditto, magnified view, ib. 6. Ditto, sectional view, with the seed just previous to projection, ib. 7. Ditto, with the seed in the act of projection, ib. 8. Ditto, immediately after projection, ib. 9. Microscopic views of apple and pear mould, 30 10. Eggs of a butterfly and of a moth, magnified, 41 11. Magnified egg of the angle-shades moth, 42 "12. Sea egg, natural size, ib. 13. V.gg of the meadow brown butterfly, magnified, 43 14. Egg of the brimstone moth, magnified, ib. 1.5. Dung-fly, with its eggs magnified, and mode of depo- sition, 44 16. Lace-winged fly, and position of its eggs on a twig of lilac, " 45 17. Ichneumon fly, with its ovipositor, magnified, 57 18. Ichneumon flies ovipositing, 58 19. Generation of ichneumons, seven figures, 62 20. Magnified view of a parasite fly {Evania apetidi- gaster), 66 21. Bee parasite {Str/lops Melittce), 67 22. Leaf-mining maggots and fly, four figures, 70 23. Gnats forming their egg-boats. 74 XU ILLUSTRATIONS. Pag« 24. Magnified view of the boat of gnats' eggs, 75 25. Female gypsey moths, and modes of depositing their eggs, four figures, 81 26. Females of the brown and gold-tailed moths, two figures, 83 27. Tweezers of the brown and gold-tailed moths, mag- nified, two figures, 84 28. Spiral groups of eggs of an unknown moth, 85 29. Eggs of the lackey moth wound spirally round a twig of hawthorn, natural size and magnified, two figures, 86 30. Eggs of the coccus, covered with down, and with the bodies of the mothers, 89 31. Magnified cochenille insects, male and female, two figures, ib. 32. Eggs of the hawthorn coccus, covered by the body of the dead mother, 91 33. Ditto, one of these magnified, ib. 34. Section of ditto, showing the eggs within, ib. 35. Suspended spiders' nests, three figures, 94 36. Vapourer moth, male and female, and deposition of eggs, three figures, 95 37. Drum of the ear, showing that there is no passage through it to the brain, 103 38. Chequered blow fly, 1 10 39. Abdomen of ditto, opened and magnified, showing the coil of young larvae, ib. 40. Coil of larva; of ditto, partly unwound, ib. 41. Large gray blow-fly, with the abdomen opened, show- ing the young maggots. 111 42. Breathing apparatus of the maggot of a large gray blow-fly, ib. 43. Spider flies, two figures, 117 44. Generation of a water-mite, four figures, 121 45. Hatching of the egg of the garden spider, four figures, 1 24 46. Egg of the privet hawk moth, magnified, showing the inclosed embryo, 125 47. Caterpillar of ditto, when grown, ib. 48. Construction of eggs to facilitate the escape of the larva;, three figures, 126 49. Supposed animal and vegetable metamorphoses, 131 50. Egg of the large cabbage butterfly, 133 51. Embryo butterflies as they appear in the bodies of ca- terpillars, two figures, 135 52. Femaje of the perfect cabbage butterfly, ib. 53. Magnified view of a section of the bud of a laburnum, 1 36 ILLUSTRATIONS. Xlll Page 54. Section of a bean-seed, 136 55. Seed-leaves, root, and first true leaf of the beech, ib. 56. Dissection of the water-grub of a May-fly, 139 57. Caterpillars of the Clifden nonpareil feeding on the gray poplar, 142 58. Ditto, in a more advanced stage of growth, l43 59. Walking-leaf insect magnified, 144 60. Transformations of the brimstone moth, 145 61. Caterpillars of the swallow-tailed moth, 146 62. A two-winged fly ( Volucellu plumata), 149 63. Transformations of the puss moth, 152 64. Lobster caterpillar, '53 65. Aquatic grubs of gnats in a glass vessel of water, 155 66. Larvae of the common-gnat, floating in water, two figures, 156 67. Buoy-like structure in the tail of a water-grub of a two-winged fly, 157 68. Telescopic-tailed water-larvae, three figures, 158 69. Water-worms, two figures, 159 70. Grub of the dragon-fly, and various parts of its body magnified, five figures, 162 71. Mask of the dragon-fly grub, four figures, 164 72. Moultingof caterpillars, and magnified views of parts, ten figures, 172 73. Exuvia and pulmonary vessels of the rhinoceros beetle, 175 74. (joat moth caterpillar escaping from a drinking-glass, 178 75. Magnified view of the dorsal muscles of the upper half ofthecossus, 182 76. Caterpillar of cossus escaping from under a loaded glass, 184 77. Methods used by spiders and caterpillars for ascending their threads, 186 78. Caterpillar of the tiger-moth, two figures, 187 79. Grub of the museum beetle, natural size and magni- fied, two figures, ib. 80. Tail of ditto, magnified, ib. 81. Hairs of ditto, magnified, two figures, ib. 82. Thorny hairs of caterpillars, three figures, 189 83. Green tortoise beetle (Cassida equestris), 191 84. Grub of ditto, magnified, to show its anal forks, ib. 85. Grub of ditto, with its canopy of excrements, ib. 86. Spit frog-hopper, and froth covering the grub of the same, two figures, 192 87. Caterpillar of the drinker moth, two figures, 194 88. Caterpillar of the angle-shades moth, ib. XIV ILLUSTRATIONS. 89. Moth of ditto, 194 90. Viscera of the cossMs, two figures, 199 91. Caterpillar of Vanessa urticn , magnified, 200 92. Intestines of ditto, ib. 93. Intestinal canals of the caterpillar, pupae, anJ butter- fly, five figures, 201 94. Buff-tip caterpillar, and moth of ditto, two figures, 204 95. Encampment of the caterpillar of the small ermine on the Siberian crab, ' 206 96. Transformations of the gamma moth, five figures, 212 97. Saw-fly of the gooseberry, and caterpillars, four figures, 214 98. Caterpillar of the saw-fly {JSTematus Caprece) on the osier, 217 99. Caterpillar of the saw-fly {Selandria alni) on the alder, ib. 100. Transformations of the grain moth, seven figures, 221 101 . Transformations of the honeycomb moth, seven figures, 223 102. Transformations of the cockchafer, nine figures, 227 103. Wire-worm and click beetle, 230 104. Zahrus gibbus, 231 105. Melolontha ruficornis, ib. 106. Corn weevil, 234 107. Meal-worm, and the beetle produced from it, 235 108. Transformations of the tabby moth, six figures, 236 109. Intestinal worms, three figures, 239 110. Churchyard beetle, in the grub and perfect state, four figures, 241 111. Nut and apple-tree beetles, eight figures, 243 112. Bark mined in rays by beetle grubs, 245 113. Locust, 251 114. Ovipositor and eggs of the crane-fly, 253 115. Crane fly ovipositing, and the larva beneath in the earth feeding upon grass roots, 254 116. Germination of a grain of wheat, 259 117. Transformation of the wheat-fly, three figures, 260 H8. The Hessian fly, 261 119. The Markwick fly, ib. 120. ' Transforn)ations of the cheese-hopper, s&ven figures, 265 121. Transformations of Bibio hortulanus, six figures, 267 122. Transformations of the lady-bird, six figures, 270 123. Transformations of the lace-winged fly and syrphus, five figures, 271 124. Caterpillar of Vanessa Antiopa, three figures, 274 ILLUSTRATIONS. XV 125. Suspended caterpillar of Vanessa Antiopa splitting its skin for the evolution of the chrysalis, four figures, 276 126. Chrysalides of Vanessa urticcB suspended, with the anal hooks magnified, and old skin fallen off, four figures, 27S 127. Black-veined white butterfly, caterpillar, and chry- salis, three figures, 280 128. Caterpillar and chrysalis of swallow-tailed butterfly, three fiipires, 281 129. Pupae of blow-fly and syrphus, four figures, 284 130. Transformations of the gnat (Corethra plumicor- nis), six figures, 287 131. Pupa of chameleon fly, three figures, 292 132. Pupa of lappit moth, three figures, 294 133. Chrysalis of Gonepteryx Rhamni, 300 134. Pupa of Laria fascelina, ib. 135. Pupa of Sphinx Ligustri, ib. 136. Spiracles of pupse, two figures, 302 137. Pupa? of the gnat and Tipula , four figures, 304 138. Transformations of Chironomus plumosus, four figures, 305 139. Case fly, with the pupa, and the grate-works of the opening of the latter, four figures, 321 140. Puptc of Cossus and Mgeria, 323 141. The fly and pupa of the ant-lion, four figures, 335 142. Transformation of the dragon-fly, five figures, 337 143. Blow-fly, magnified, two figures, 338 144. Wings of insects, showing the nervures, six figures, 344 145. Twenty-plume moth, two figures, 345 146. White-plume moth, ib. 147. Specimens of deformed butterflies and moth, three figures, 350 148. Red spider, and the head, magnified, two figures, 359 149. Head of the garden spider magnified, ib. 150. Phalancrium, 360 151. Hydrometra stagnoruin , magnified, ib. 152. Plniaria vagabunJa, magnified, 381 153. JVeides elegans, magnified, ib. 154. Hydrometra stagnoruin, natural .size, 382 155. Hydrachna geographica, magnified, two figures, ib. 156. Velia rivulorum, ib. 157. Jnlus terrestris, two figures, 386 158. Oil-beetle, ib. XVI ILLUSTRATIONS, 159. JVycteribia Hermanni, 386 160. Feet of the fly, greatly magnified, four figures, 391 161. Flea, magnified, 392 162. Velvet spring-tail, magnified, 394 163. American spider ( Mygale avicularia) destroying a bird, 395 164. Muscular ribbons for moving the wings in Syrphus inanis, magnified, two figures, 397 165. Syrphus, 398 INSECT TRANSFORMATIONS. SECTION I.— EGGS OF INSECTS. Ch.- All Insects come from Eggs as Plants do from feeds. — Vnlgnr errors of lusects being generated by Futiefactiou anJ Blighting Winds disproved by experiment. It was universally believed by the ancient philoso- phers, that maggots, flics, and other insects were generated from putrefying substances. This opinion continues to be held by uninformed persons among ourselves; — though it would be equally correct to maintain, that a flight of vultures had been generated by the dead carcass which they may be seen devour- ing, or a flock of sheep from the grass field in which they graze. Another opinion, perhaps still more gene- rally diffused, is that caterpillars, aphides, and other garden insects which destroy the leaves of plants, are generated, propagated, or, at least, spread about, by certain winds or states of the air, mysteriously and indefinitely termed blight. The latter belief is, pro- bably, not so easy of immediate refutation as the for- mer;— but, as we shall endeavour to show, it seems to us to be equally erroneous. The small size of insects renders it somewhat easy to pass otr fanciful opinions regarding them, since it is difficult for common observers to detect mistakes, VOL, VI. 1 'Z INSECT TRANSFORMATIONS. but similar notions have been entertained by writers of no mean reputation, respecting even the larger animals. The celebrated Kircher, for example, one of the most learned men of the seventeenth century, goes so far as to give the following singular recipe for the manufacture of snakes : — ' Take some snakes,' says he, ' of whatever kind you want, roast them, and cut them in small pieces, and sow those pieces in an oleaginous soil; then, from day to day, sprinkle them lightly with water from a watering-pot, taking care that the piece of ground be exposed to the spring sun, and m eight days you will see the earth strewed with little worms, which, being nourished with milk diluted with water, will gradually increase in size till they take the form of perfect serpents. This,' he subjoins with great simplicity, ' I learned from having tbund in the country the carcase of a serpent covered with worms, some small, others larger, and others again that had evidently taken the form of serpents. It was still more marvellous to remark, that among these little snakes, and mixed as it were with them, were certain flies, which I should take to be engen- dered from that substance which constituted the aliment of the snakes.'* Kircher's more shrewd and less fanciful cor- respondent, Redi, determined to prove this singular recipe before he trusted to the authority of his friend. * Moved,' he says, * by the authentic testimony of this most learned writer, I have frequently tried the experiment, but I could never witness the genera- tion of those blessed snakelets made to hand.|' But though Redi could not, in this way, produce a brood of snakes, his experiments furnished an abundant progeny of maggots, — the same, unques- • Athan. Kircher, Mund. Subterran. lib. xii. t Redi, General. lusectorum, edit. Amstel. 1686. GENERATION OP INSECTS. 3 tionably, that the imagination of Kircher had magni- fied into young snakes, — which, being confined m a covered box, were in a short time translbrmed into flies, at first of a dull ash colour, wrinkled, un- finished, and their wings not yet unfolded, — as is always the case with winged insects just escaped from their pupa case. In less than an h(Mr, how- ever, they ' unfolded their wings, and changed into a vivid green, marvellously brilliant ' — most proba- bly the green flesh-fly {Muaca Ccesar. Linn.) It is a common opinion in this country, particu- larly in the north, that if a horse's hair be put into the water of a spring or a ditch, it will be in process of time transtbrmed, first into a hair-worm, and afler- wards into an eel. The deception, as in the instance of Kircher's snakes, arises from the close resemblance between a hair and the hair-worm {Gordlns aquati- ctis, Linn.), and between liiis and a young eel. This fabled transformation of hair, which we have heard maintained even by several persons of good educa- tion, is physically impossible and absurd. The method laid down by Virgil in his Georgics for generating a swarm of bees is precisely of the same description as the snake recipe of Kircher; and tliough the ' Episode of Arista'us recovering his bees' has been pronounced to be ' perhaps the linest piece of poetry in the world,' we must be permitted to say that it is quite fabulous and unphilosophical. The passage runs thus : — Oft from putrid gore of cattle slain Bees have been bred. * * * A narrow place. And for that use contracted, first they choose. Then more contract it, in a narrower room, Wall'd round, and cover d with a low built roof. And add four windows, of a slanting liglit From the four winds. A bullock then is sought. His horns just bending in their second year; 4 INSECT TRANSFORMATIONS. Him, much reluctant, with o'erpow'ring force. They bind; his mouth and nostrils stop, and all The avenues ef respiration close; And buffet him to death: his hide no wound Receives; his batterd entrails burst within. Thus spent they leave him; and beneath his sides Lay shreds of boughs, fresh lavender and thyme. Thi^ when soft zephyr's breeze first curls the wave, Anaprattling swallows hang iheir nests on high. Meanwhile the juices in the tender hones Heated ferment; and, wondrous to behold. Small animals, in clusters, thick are seen. Short of their legs at first: on filmy wings, Humming, at length they rise; and more and more Fan the thin air; 'till, numberless as drops Pour'd down in rain from summer clouds, they fly.' Trapp's Virgil, tieorg. iv, 369. Columella, a Roman writer on rural affairs, after directing in what manner honey is to be taken from a hive by killing the bees, says, that if the dead bees be kept till spring, and then exposed to the sun among the ashes of the hg-tree, properly pulverised, they may be restored to life. These fancies have evidently originated from mis- taking certain species of flies {Syrphi, Bombylii, &c,) for bees, which, indeed, they much resemble in general appearance ; though they have only hvo wings, and short antennce, while all bees have four wings, and long antennae. ISeither the flies nor the . Comparative figures of a bee (a) and a sj rphus (b). bees are produced by putrefaction; — but as the flies are found about animal bodies in a state of decom- position, the ancients fell into an error which accurate observation alone could explode. The maggots of CENEUATIOX OP I.VSECTS. 5 blow-flics, as Swammcidain remarks, so often found in the carcasses of animals in summer, * somewhat resemble those produced by the eggs of bees. How- ever ridiculous,' he adds, ' the opinion must appear, nianv great men have not been ashamed to adopt and defend it. The industrious Goedart has ventured to ascribe the origin of bees to certain dunghill worms,* and the learned De Mci joins with him in this opi- nion; though neither of them had any observation to ground their belief upon, but that of the external re- semblance between bees and certain kinds of flies {Stjrphid(v) produced from those worms. The mis- take of such authors should teach us,' he continues, ' to use great caution in our determinations concern- ing things which we have not thoroughly examined, or at least to describe them with all the circum- stances observable in them. Therefore, although this opinion of bees issuing from the carcasses of some other animals by the power of putrefaction, or by a transposition of parts, be altogether absurd, it has had, notwithstanding, many followers, who must have in a manner shut their eyes in order to embrace it. But whoever will attentively consider how many requisites there are for the due hatching of the bee's egg, and for its subsistence in the grub state, cannot be at a loss for a clue to deliver him- self out of that labyrinth of idle fancies and unsup- ported fables, which, entangled with one another like a Gordian knot, have even to this day obscured the beautiful simplicity of this part of natural history. 'I Redi was by no means satisfied with the first re- sults of his experiments upon the flesh of snakes, for * The ma£f;ots of Eristalis tcnax, Fabr. E. apiformis, Meigen, and otlier Si/rjihido', well Unowu ia common sew- ers by their loug tails, like those of rats. t Swammerd. Book of Nature, i, 228. VOL. VI. 1* b INSECT TRANSFORMATIONS, several species of flies were produced, giving some countenance to the opinion of Aristotle, Pliny, Mouf- fet, and others, that different flesh engenders different flies, inheriting the disposition of the animal they are bred from. He accordingly tried almost every species of flesh, fish, and fowl, both raw and cooked, and soon discovered (as he could not fail to do) that the same maggots and flies were produced indis- criminately in all. This ultimately led him to ascertain that no maggots are ever generated except from eggs laid by the parent flies: for when he carefully covered up pieces of meat with silk or paper sealed down with wax, no maggots were seen; but the parent flies, attracted by the smell of the covered meat, not unfrequently laid their eggs on the outside of the paper or silk, the maggots hatched from these dying, of course, for want of nourishment. With respect to bees, it becomes even more absurd to refer their generation to putrefaction, when we consider that they uniformly manifest a peculiar antipathy to dead carcasses. This was remarked so long ago as the time of Aristotle and of Pliny;* and Varro asserts that bees never alight upon an unclean place, nor upon any thing which emits an unpleasant smell. This is strikingly exemplified in their carrying out of the hive the bodies of their companions who chance to die there; and in their covering over with propolis the bodies of snails, mice,"!" and other small animals which they cannot re- move. J These facts, which are unquestionable, may at first view appear to contradict the Scripture history ** Aristotle, Hist. Animal, ix, 40. Pliny says, ' Omnes car- ne vescuntur, contra quam apes, quae nullum corpus attingutit.' t Huish on Bees, p. 100. t Insect Architecture, p. 109. GE.VERATIOX OP INSECTS. 7 of Samson, who, having killed a young lion in the vineyards of Tininath, ' after a time turned aside to see the carcass of the lion: and behold a swarm of bees and honey in the carcass.'* It only requires us, however, to examine the facts, to show that this does not disagree with the preceding statement, Bochart, in his Sacrod Zoology, tells us that the word rendered ' carcass' literally signifies skehlon; and the Syriac version still more strongly renders it a dried body (corpus c.xsiccatum). Bochart fur- ther contends, that the phrase ' after a time' is one of the commonest Hebraisms for a year. But when we consider the rapid desiccation caused by the sum- mer suns of Palestine, this extension of time will be unnecessary; for travellers tell us that the bodies of dead camels become quite parched there in a few days. We have the testimony of Herodotus, that a swarm of bees built their cells and made honey in the dried carcass of a man placed above the gate of Athamanta. Soranus also tells us of a swarm of bees found in the tomb of the celebrated Hippocrates. * I have been told,' says Rcdi, ' by Albergotto, a man of profound erudition, that he had seen a swarm in the cranium of a horse. Bees,' he adds, * not only do not live upon dead bodies, but they will not even come near them, as I have often proved by ex- periment.' ' It is probable,' says Swammerdam, ' that the not rightly understanding Samson's ad- venture of the lion gave rise to the popular opinion of bees springing from dead lions, oxen, and horses.' Kirby and Spense seem disposed to consider Sam- son's bees, as we have done those of Virgil, to be flies resembling bees; but the ' honey' which Samson ' took in his hands and went on eating,' is fatal to such an exposition. The ancients had another fancy respecting the * Judjres, xiv, 8. 8 mSECT TIIANSFORMATIONS. propagation of bees, equally absurd, tbough much more poetical, Virgil tells us that. From herbs and fragrant flowers, with their moutlis They cull their young. Georg. iv. Aristotle* had long before stated, and De Monfort in modern times repeated the assertion, "j" that the olive, the cerinthus, and some other plants, have the property of generating young bees from their purest juices. We may well say, with Lactantius, that ' they make shipwreck of their wisdom, who adopt without judgment the opinions of their ancestors, and allow themselves to be led by others like a flock of sheep. 'J Modern naturalists, being accustomed to minute accuracy in their observations, can both disprove and readily explain most of those erroneous fancies, by tracing the causes which led, and may still lead, inaccurate observers into such mistakes. It would have been well if such unfounded fancies had rested here; but philosophical theorists, both of ancient and modern times, have promulgated dreams much more extravagant. The ancients taught that the newly-formed earth (hatched as some said from an egg) clothed itself with a green down like that on young birds, and soon after men began to sprout up from the ground as we now see mushrooms do. The refined Athenians were so firmly convinced of their having originally sprung up in this manner, that they called themselves ' Earth-born' (^Erich- ihonii), and wore golden tree-hoppers {Cicadoi) in their hair, erroneously supposing these insects to have a common origin with themselves. § Lucretius * Hist. Animal, v, 22. t Le Portrait de la INIouche a IMiel. Liege, 1646. t Diviu. lustit. ii, 7; in Redi's motto. Shepherds on the continent lead their sheep, as those of Israel did. See Mena- geries, vol. i, p. 81. § The Cicadas do not deposit their eggs in the earth, but on trees, &c. See Insect Architecture, chap. viL GENERATION OF INSECTS. y affirms, that even in his time, when the earth was sup- posed to be grow ing too old to be reproductive, ' many animals were concreted out of mud by showers and sunsiiine.'* But the ancients, it would appear, had the shrewd- ness seldom to venture upon illustrations of their phi- losophical romances by particular examples. This was reserved for the more reckless theory-builders of our own times. We find Robinet, for example, asserting that, as it was nature's chief oi)ject to make man, she began her ' apprcntissage,' as he calls it, by forming minerals resetiil)ling tiic single organs of the human body, such as the brain in the fossil called Brain-stone {Mcandnna ciribi-iformis, Parkinson.)! Darwin, again, taking the hint from Epicurus, dreams that an- imals arose tiom a single filament or threadlet of mat- ter, which, by its efforts to procure nourishment, lengthened out parts of its body into arms and other members. For example, alter this filament had im- proved itself into an oyster, and been by chance left dry by the ebbing of the tide, its efTorts to reach the water again expanded the parts nearest to the sea in- to arms and legs. If it tried to rise from its native rocks, the efforts produced wings, and it became an insect, which in due course of time improved itself by fresh efforts till it became a bird, the more perfect members being always hereditarily transmitted to the progeny. The ditterent forms of the bills of birds, whether hooked, broad, or long, were, he says, gradu- ally acquired by the perpetual endeavours of the crea- tures to supply their wants. The long-legged water- * Multaque nunc etiam existunt aDinialia terris, Inibribuset calido soIi3 concieta vapore. De jVut. Rer. v. 795. t Robinet, Consid. Philosophiques de la Gradation Natarelle dea Formea de TEtre. Paris, 1768. 10 INSECT TRANSFORMATIONS. fowl {Grallatores ^ Vigors) in this way acquired length of legs sufficient to elevate their bodies above the water in which they waded. ' A proboscis,' he sa)s, ' of admirable structure has thus been acquired by the bee, the moth, and the humming-bird, for the purpose of plundering the nectaries of flowers.'* La- marck, an eminent French naturalist, recently deceas- ed, adopted the same visions; and, among other illus- trations of a similar cast, he tells us that the giraffe acquired its long neck by its efforts to browse on the high branches of trees, which, after the lapse of a few thousand years, it successfully accomplished. Theories like the preceding all originate in the en- deavours of human ingenuity to trace the operations of nature farther than ascertained facts will warrant ; and the necessary blanks in such a systeni, which presupposes much that cannot be exphiined, are filled up by the imagination. This inabihty to trace the origin of minute plants and insects led to the doctrine of what is called spontaneous or equivocal generation, of which the fancies above-mentioned are some of the prominent branches. The experiments of Redi on the hatching of insects from eggs, which were pub- lished at Florence in 1668, first brought discredit up- on this doctrine, though it had always a few eminent disciples. At present it is maintained by a consider- able number of distinguished naturalists, such as Blumenbach, Cuvier, Bory de St Vincent, R. Brown, &.C. ' The notion of spontaneous genera- tion,' says Bory, ' is at first revolting to a rational mind, but it is, notwithstanding, demonstrable by the microscope. The fact is averred: Miiller has seen it, I have seen it, and twenty other observers have seen it : the Pandorinia exhibit it every instant. '| * Darwin's Zoonomia, sect, xxxi.x, 3d edit. London, 1801. t Diet. Classiquo d'Hist. Nat., Art. Microscopiques, p, 541. GENERATION OF INSECTS. 1 1 Tliese pandorinia he elsewhere describes as probably nothing more than ' animated scions of Zoocarpae' (propagules aninie.s dcs Zoocarpcs.)* It would be unprohtable to go into any lengthened discussion upon this mysterious sul)ject ; and we have great doubts whether the ocular demonstration by the microscope would succeed except in the hands of a disciple of the school. Even with naturalists, whose business it is to deal with facts, the reason is often wonderfully influ- enced by the imagination. But the question immediately before us happily does not involve tliese recondite discussions ; for if even pandorinia and other animalcules were proved beyond a doubt to originate in the play of chemical affinities or galvanic actions — (a more refined process, it must be confessed, than Kircher's chopped snakes), it would not affect our doctrine that all insects are hatched from eggs : for no naturalist of the present day classes such animalcules among insects. Leaving animal- cules and zoophytes, therefore, out of the question, we have only to examine such branches of the»theory of Sj)ontaneous generation as seem to involve the pro- pagation of genuine insects, — like the fancies about putrefaction which we have seen refuted. The notion that small insects, such as aphides and the leaf-rolling caterpillars, are spread about, or rather generated, by what is termed blight (possibly from the Belgic blinkan, to strike with lightning), is almost universally believed even by the most intel- ligent, if they have not particularly studied the hab- its of insects. Mr Main, of Chelsea, an ingenious and well-informed gardener and naturalist, describes this as an ' easterly wind, attended by a blue mist. The latter is called a blight, and many people imagine that the aphides are walled through the * Diet, Class., Art. Pandorinc es. 12 INSECT TRANSFORMATIONS. air by this same mist.'* ' The farmer,' says Keith, ' supposes these insects are wafted to him on the east wind, while they are only generated in the ex- travasated juices as formino; a proper nidus for their eggs. 'I A more detailed account, however, is given by the late Dr Mason Good, and as he speaks in part from personal observation, and was not only one of the most learned men of his time, but an ex- cellent general naturalist, his testimony merits every attention : — ' That the atmosphere,' says Dr Good, ' is freight- ed with myriads of insect eggs that elude our senses, and that such eggs, when they meet Avith a proper bed, are hatched in a few hours into a perfect form, is clear to any one who has attended to the rapid and wonder- ful effects of what, in common language, is called a blight upon plantations and gardens. 1 have seen, as probably many who read this work have also, a hop- ground completely overrun and desolated by the aphis humuli, or hop green-louse, within twelve hours after a honey-dew (which is a peculiar haze or mist loaded with poisonous miasm) has slowly swept through the plantation, and stimulated the leaves of the hop to the morbid secretion of a saccharine and viscid juice, which, while it destroys the young shoots by exhaus- tion, renders them a favourite resort for this insect, and a cherishing nidus for myriads of little dots that are its eggs. The latter are hatched within eight and Forty hours after their deposit, and succeeded by hosts of other eggs of the same kind; or, if the blight take place in an early part of the autumn, by hosts of the young insects produced viviparously; for, in different seasons of the year, the aphis breeds both ways. Now it is highly probable that there are minute * Loudon's Mag. of Nat. ITist. i, ISO. t Keith's Physiological Botauy, ii, 486. GENEUATIOX OF INSECTS. 13 eggs or ovula, of irinumerablo kinds of animalcules floating by myriads of myriads through the atmo- sphere, so diminutive as to bear no larger proportion to the eggs of the aphis than these boar to those of the wren or the hedge-sparrow; protected at the same time from destruction, by the lilmy integument tliat surrounds them, till they can meet with a proper nest for their reception, and a proper stimulating power to quicken them into life; and which, with respect to many of them, are only found obvious to the senses in ditferent descriptions of animal fluids.'* It appears to us that it can be nothing more than a fancy, which is quite unsupported by evidence, to say that the eggs of any species of animalcules or insects float about in the atmosphere; for, independent of their weight, (every known species being greatly heavier than air,) the parent insects of every species whose history has been accurately investigated mani- fest the utmost anxiety to deposit their eggs upon or near the appropriate food of the young. To commit them to the winds would be a complete dereliction of this invariable law of insect economy. But admit- ting for a moment this hypothesis that the eggs of insects are difllised through the atmosphere, the cir- cumstance must be accompanied with two conditions, — the eggs must either be dropped by the parents while on the wing, or be carried oft' by winds fiomthe terrestrial substances upon which they may have been deposited. On the supposition that the eggs are dropped by the mother insects while on the \\ ing, we must also admit (for there is no avoiding it) that they continue to float about, unhatched, from the end of the summer till the commencement of spring, at which time only the broods make their appearance. Yet when we * Cood's Study of Medicine, v. i, p. 339, 3rd edition, Lon- don, 1829. 14 INSECT TRANSFORMATIONS. consider the rains, snows, and winds, to which they must be exposed for six or nine months, we think the hardest theorist would scarcely maintain that a sin- gle egg could out -weather these vicissitudes, and con- tinue to float in the air. It may not be out of place to remark, that the female aphides, which deposit eggs in autumn, have no wings. Again, on the supposition that the eggs are de- posited on plants, trees, or other objects, it is still more unlikely that they could be carried into the air; for, on exclusion, they are, with very few exceptions,* enveloped in an adhesive cement which glues them to the spot on which they are deposited. When eggs are deposited singly, this cement usually enve- lopes each with a thin coating, as in the instance of the admirable butterfly ( Vanessa Jltalanla) ; but when they are placed in a group the cement is some- times spread over the whole, as in the instance of the white satin moth {Leucoma salicis, Stephens). This cement is evidently intended by Nature (who seldom accommodates her plans to our theories) to prevent the eggs from being carried from the place se- lected by the mother insect ibr their deposition. Those eggs, therefore, which are placed on the outside of substances, have this provision for their secure attach- ment to the locality chosen by the instinct of the mother. But, on the contrary, the principle does not always hold in the case of those deposited in nests and exca- vations, and particularly as to those of ants and ter« mites. The working ants, indeed, carry the eggs from the top to the bottom of their galleries, according as the weather is favourable or unlavourable for hatching. The labourers of the white ants {Tcrmilcs), again, at- tend their queen with the utmost care when she is lay- ing; for as she cannot then move about, they are under the necessity of carrying off" the eggs, as they are laid, * Latreille, Hist. Ggner, xiv, p. 342. GENERATION OF INSECTS. 15 to the nurseries. The extraordinary labour which this requires in the community may be understood, when, according to Smeathman, she lays GO eggs in a minute, which will amount to 86,400 in a day, and 31,536,000 in a year. The exceptions now mentioned, howev- er, do not in the least invalidate our general posi- tion. Cell ol" a queen ol' tlit Tiriiiitrs billico^i, broM-ii open m uum -, labuurers suirouiiiliug the queen and carrying off her eggs. Another no less remarkable circumstance is the great weight, or specific gravity, of the eggs of in- sects. From numerous experiments we rnay venture to say that tliose of all the species which we have tried sink rapidly in water the moment they are thrown into it, from the egg of the drinker moth {Odo- nestis Polutoria, Germar), which is nearly as large as a hemp-seed, to that of the rose-plant louse {Aphis rosce\ which is so small as to be barely visible to the naked eye. Some eggs of the gipsey moth {Hypo- gymna dispar, Stephens), indeed, floated in water, because they were covered with down. It is well known, as we shall pres^Mitlv sliow, that the diffu- sion of many of the seeds of plants is accomplished by the winged down with which they are clothed j INSECT TRANSFORMATIONS. but the down upon the eggs of insects does not con- duce to this end. Whether insect eggs be naked or clothed with down, they are invariably, as far as their history has been investigated, deposited close to or upon substances capable of affording food to the young when hatched. In making experiments upon the spe- cific gravity of eggs, it should be remembered that no infertile or unimpregnated egg will sink; for having some hundreds of these laid by different species of insects reared in our cabinet, we found, upon trial, that they uniformly floated, while those which we knew to be impregnated as uniformly sunk. A female, for example, of the rose-leaf roller [Lozoicenia Rosana, Stephens) was reared by us, in solitude, under an inverted wine-glass, upon the side of which she glued a patch of eggs, of course, unimpregnated: these, upon trial, all floated in water. But eggs of the same species taken from the outside of a pane of glass close to a rose-tree, all sunk in water; and it is to be fairly presumed, as the parent of the latter was in a state of freedom, that these were impregnated. We found the same distinction, indeed, to hold in the eggs of the drinker moth, the gypsey moth, and numerous other insects.* Dr Good's account of ' honey-dew,' Mhich he des- cribes as ' a peculiar haze or mist loaded with a poi- sonous miasm,' that stimulates ' the leaves of the hop to the morl)id secretion of a saccharine and viscid juice' — appears to us unsupported by facts. Lin- najus,"]" on the contrary, who was not wedded to the meteorological theory of a miasmatous haze, ascribes the honey-dew on the hop leaves to the caterpillar of the ghost moth {Hcpialits Jmmidi) attacking the roots, Dr Withering, favouring this account, recommends covering the roots with stones as a preventive; for * J, R. t Quoted by Keith, Phys. Bot. ii, 143. GENERATION OF INSECTS. 17 the caterpillars, he avers, never attack wild hops which grow in stony places, because they cannot get at the roots.* It appears to us, however, that there can be little doubt that the sweet syrupy coating, called honey-dew, found on the leaves of the hop, is nothing more than the excrement of the insect {^iphis liuiinili) whose propagation we are discussing. ' The honey-dew,' says Loudon, ' mostly' (we believe always) ' occurs after the crops have been attacked by these insects. '| Sir J. E. Smith, who admits this to be the common cause of honey-dew, contends that what is found on the leaves of the beech is an exception; but he adduces no evi- dence at all satisfactory in proof of its being caused by unfavourable winds ;t while the undoubted fact of its being the excrement of aphides in so many other instances^ weighs strongly against him. A novel theory of honey-dew has just been pub- lished by JMr John JMurray, who ascribes it to an electric change in the air. ' Last summer,' he says, ' we investigated the phenomenon with great care: the weather had been {)arched and sultry for some weeks previous, and the honey-dew prevailed to such an extent, that the leaves of the currant, raspberry, &c, in the gardens, literally distilled from their tips a clear hmpid honey-dew, excreted Irom the plant; for the phenomenon was observable on those plants that were entirely free from aphides, and so copious was it, where these insects were found, that had their numbers been centuple they could not cer- tainly have been the source of the supply. The question with me, however, was set at rest by ap- plying a lens, having previously washed and dried • Botan. Arrangement, ii, 440, 3d ed. + Encycl. of Agriculture, ^865, s. 5444. t Introduction to Botany, fF 189, § See Linn. Trans, vol. vi, andWilldenow, Princ. of Bota- ny, p. 343. VOL. ri. 2* 18 INSECT TRANSFORMATIONS. the leaf by a sponge, for in this case the immediately excreted globules became apparent.'* In all observations upon insects, and the other minute parts of creation, it is often exceedingly dif- ficult to distinguish between a cause and an effect. The question of the formation of honey-dew appears to us particularly liable to erroneous conclusions; and we therefore venture to mention a few circumstances which seem irreconcilable with ]Mr jVIurray's inge- nious theory The hop fly {Aphis hiimuli), we think, neither does, nor (tor want of appropriate organs) can, feed on the honey-dew; and if it did, this feed- ing would prove rather beneficial than otherwise to the plant, by clearing it from the leaves whose respi- ratory functions it obstructs. So far from feeding on diseased plants, an aphis only selects the youngest and most healthy shoots, into the tender juicy parts of which it thrusts its beak {hausttUum), which in some species is much longer than the body, and no more fitted for lapping honey-dew than the bill of iEsop's crane was for eating out of a shallow plate. In the experiment, tried by ]\Ir INIurray, of wiping a leaf, might not the leaf have been previously wounded, perhaps, by the beak of some aphis, and hence the exudation of sap, not honey-dew? and may not the circumstance of his finding the honey-dew on leaves where there were no aphides be accounted for on the principle that the aphides had abandoned, as they always do, the parts covered with their ejecta, unless these fell from insects on some over-hanging branch? It is justly remarked by M. Sauvages, that they are careful to eject the honey-dew to a distance from where they may be feeding. I We have now in our study a plant of the Chinese chrysanthemum {Anthemis tirtemisice folia, Willd.), the young * Treatise on Atinosplierical Electricity, p. 147, Loud. 1S30. t Trans. Soc. Roy. de Montpellier. GEXERATION OF INSECTS. 19 shoots of which have swarmed with aphides all tlie winter, and the leaves below arc covered with honey- dew. We tried tiie experiment of wi|)ing it off from a leaf, but no more was Ibrmed when it was protected by a piece of writing-paper from the aphides above; while the writing-paper became sprinkled all over with it in a lew hours. By means of a lens, also, we have actually seen the aphides ejecting the honey- dew.* The almost instantaneous appearance of these des- tructive insects in great numbers at the same time, is taken notice of with wonder by almost every writer. This circumstance, it must be confessed, gives con- siderable plausibility to the notion of their being brought by winds, — for whence, we may be asked, could they otherwise come ? Simply, we reply, from the eggs deposited the preceding autumn, which, hav- ing ail been laid at the same time, and exposed to the same degrees of temperature, are of course all simul- taneously hatched. In the case of the aphides, also, the fecundity is almost incalculable. Reaumur pro- ved by experiment, that one aphis may be the pro- genitor of 5,904,900,000 descendants during its life; and Latreille says, a female during the summer months usually produces about twenty-live a day. Reaumur further supposes, that in one year there may be twenty generations. We ourselves have counted more than a thousand aphides on a single leaf of the hop; and in seasons when they are abundant — when every hop-leaf is peopled with a similar swarm — the number of eggs laid in autumn must be, to use the words of Good, ' myriads of myriads.' The pres- ervation and hatching of these eggs in the ensuing spring must, it is obvious, depend on the weather and * J. R. 20 INSECT TRANSFORMATIONS, other accidental circumstances, seldom appreciable by our most minute observations.* The history of other insects, erroneously referred to blighting winds, is more easily traced, from their being of a larger size than the aphides. The cater- pillar for example, of Lozotcenia Rosana, mentioned before, which rolls the leaf of the rose-tree, is one of this kind. It is well known as furnishing the common poetical comparison of ' a worm i' the bud.' Early in autumn the mother insect deposits an irregularly oval-patch of yellowish eggs, covered with a cement Two groups of eggs of the Rose-leaf roller (Lmotania Rota 7ia;oii a pane of glass. J. R. GENERATION OP INSECTS. 21 of the same colour, sometimes upon the branches of the rose-tree, but more frequently, as we have ob- served, upon some smooth object contiguous. For several successive seasons, we have found more than one group of these eggs upon the glass panes, as well as the tiame work, of a window, beneath which a rose-tree has been trained. At present (January 1830) there are two of these groups on one pane, and three on the frame-work; and as each contains about fifty eggs, should they all be successfully hatch- ed, two or three hundred caterpillars would at once be let loose, and, streaming down simultaneously upon the rose-tree beneath, would soon devonr tho greater number of its buds. As the wiridow faces the east, the sudden appearance of the insects would make it appear not unplausible that they had been swept hither by an easterly wind. We found, durinir the same winter, an extraordina- ry number of similar groups of the eggs of a leaf- roller [Lozolccnia Ribccnia'i) on the branches of the gooseberry and red-currant, in a garden at Lee. On some small trees, from two to ten groups of eggs were discovered; and as each group consisted of from thirty to lifty, a caterpillar might have been hatched for every bud. After the severity of the season was over, we had the piece of bark cut off on which these eggs were attached; and though they had been exposed on the bare branches to the intense frosts of 1829-30, they were hatched in a few days after being brought into our studv. As the currant- trees were not then come into leaf, we had no ibod to supply them with, and they refused the leaves of all other plants which we otTered to them. Had they been permitted to remain on the trees till they were hatched, they would probably have not left a single leaf undevoured. For this spring, at least, these currant bushes will be safe from their attacks, and of 22 INSECT TRANSFOUMATIONS. course will set at defiance, the supposed blighting winds, which no doubt will, as usual, be accused of peopling the adjacent gardens with caterpillars. It may be well to remark, that these caterpillars, when hatched, are scarcely so thick as a thread of sewing silk, and being of a greenish colour, they are not read- ily found on the leaves, the opening buds of which they gnaw to the very core.* It does not seem to have ever occurred to those who thus speak of insectiferous winds, that they get rid of no difficulty by the supposition; for where, we may ask, is the east or any other wind to take up the insects or eggs which it is said to drift along? The equally sudderi disappearance of insects all at once, which is also popularly attributed to winds, arises from their having arrived at maturity, and fulfilled the designs of Providence, by depositing their eggs for the ensuing season, when they all die, some in a few hours, though others survive for several days, but rarely for weeks. The sudden and simultaneous appearance of great numbers of frogs, snails^ and other land animals, has given rise to the extravagant opinion that they have fallen in a shower from the clouds; and some goodly theories have been devised to account for the pro- bable ascent of frog-spawn, and the eggs of snails, into the atmosphere by whirlwinds. The impossi- bility of this, in consequence of their specific gravity, is of course left out of consideration by the theorists. Our distinguished naturalist, Ray, when riding one afternoon in Berkshire, was much surprised at seeing an immense multitude of frogs crossing his path, and on looking into the adjacent fields he found that two or three acres of ground were nearly covered with them. They were all proceeding in ihe same direc- tion towards some woods and ditches; and he traced * J. R. GENERATION OF INSECTS. 23 them back to the side of a very large pond, which, in spawning time, he was informed, swarmed with count- less numbers of frogs. He naturally concluded, there- fore, that, instead of having been prcci|)itated from the clouds, they had been bred in the pond, from which they had been invited a short time before, by a re- freshing shower, to go in quest of food.* Their great numbers will appear less marvellous, when we consid- er that a single frog spawns, as De JMontbeillard in- forms us, about 1300 eggs.t Were it not, indeed, for their numerous enemies, and their not being fit to propagate till they are three years old, the country would soon be overrun with these reptiles. We have more than once seen a similar legion of hair-worms (Gordii aquatki, LiNN.) in a garden at Lee, in Kent, every plant and spot of ground literally swarming with them. Their numbers, however, were easily account- ed for, as a stream at the bottotn of the garden abounds with them, and, like frogs, they appear to be amphibious J The errors of theory, as well as the mistakes of observers, swayed (unconsciously perhaps) by the influence of their theoretical opinions, may all be traced, we think, to the propensity of human nature to discover resemblances in things, which are after- wards magnified into close affinity, or even into identity. We are indebted to one of our best living entomologists, INIr W. Mac Leay, for clearly point- ing out the broad distinction between analo^ij and affinity.^ The supposed floating of the eggs of insects in the air thus appears to have originated in drawing an analogy from the seeds of plants; though, from the facts we have stated, so far from there being any * Ray's Wisdom of f»od in the Creation, p. 156. t Diet. Clitssique dMlist. .Nat., vii, p. 495. t J. R. } Horae Entomologicse, or Essays on Annulose Animals, 8vo. London, 1819-21. 24 INSECT TRANSFORJNIATIOXS. analogy, there is no difference more marked than in this very point — that the eggs of insects are, in most cases, fixed by a gkie at the moment of exclusion, while the seeds of plants are no less uniformly diffusable and free. The fertile seeds of plants, it is true, are heavy enough to sink in water, and consequently as much unfitted for floating in the air as the eggs of insects; but the contrivances to counteract this exemplify some of the most beautiful provisions of nature. The diffusion of the seeds of thistles, groundsel, dandelion, &c, by means of feath- ery down, attracts the notice of the most incurious. Another contrivance of nature for effecting the same purpose is not only curious in itself, but bears upon our present subject as illustrating an aflinity which it may be supposed to have with the ovipositing of certain insects. The seeds of the various species of violets are contained in a capsule of a single cell, or loculament, consisting, however, of three valves. To the inner part of each of these valves a seed is attached, and it remains so for some time alter the valves, in the process of ripening, have separated and stood open. The influence of the sun's heat causes the sides of each valve to shrink and collapse; and in this state the edges press firmly upon the seed; which, it may be remarked, is not only extremely smooth, polished, and shining, but regularly egg-shaped. Thus, when the collapsing edge of the valve slides gradually and forcibly down over the sloping part of the seed, it is thrown with a jerk to a considerable distance There is another part of the contrivance of nature for the same purpose, in the violacefe, worthy of remark. Before the seed is ripe, the capsule hangs in a droop- ing position, with the persisting cal}x spread over it like an umbrella, to guard it iiom the rain and dews, which would retard the process of ripening: but no DISPERSION OP SEEDS. "ZO sooner is the ripening completed, than the capsule becomes almost upright, with the calyx for a support. This position appears to be intended by nature to give more elFect to the valvular mechanism ['or scattering the seeds, as the capsule thus gains a higher eleva- tion (in some cases more than an inch) trom which to project them. Some ripe capsules of a tine variety of heart's-ease {Viola tricolor), which I placed in a shallow pasteboard box, in a drawer, were ibund to have projected their seeds to the distance of two feet. From the elevation of a capsule, therefore, at the top of a tall plant, these seeds might be projected twice or thrice that distance.* We may mention, as another very curious illustra- tion of the power in plants of discharging their seeds, the remarkable instance of a minute timgus {Splurro- bolus stcllatus, Toue). This plant has the property of ejecting its seeds with great force and rapidity, and with a loud cracking noise; and yet it is no big- ger than a pin's head.j The circumstance alluded to as analogous in in- sects to this admirable contrivance, occurs in the forcible discharge of the eggs of some species to a distance. The ghost moth {Hepiahts humuH), for example, ejects its minute black eggs with so much rapidity, that De Geer describes them as running from the oviduct; and they are sometimes for- cibly thrown out like pellets from a pop-gun. J ' A friend of mine,' says Kirby, ' who had observed with attention the proceedings of a common crane- fly {Tipulo), assured me, tiiat several females which he caught projected their eggs to the distance of more than ten inches. '§ Another instance is men- * J. R. in Mag. of Nat. Hist., i. 3S0. •t For a minute account of this singular plant, see Grevill's Scottish Cryptoganiic Flora, No. xxxii. t De Tieer, M m. dos Insects, iv, 491. § Kirby and Speucc, Intr. iii, 66. VOL. VI. 3 26 INSECT TRANSFORMATIONS, tioned by the Abbe Preaux, of a four-winged fly, called by him, Mouche baliste, which, when caught, jets out its eggs at intervals, as if by the jerk of a spring.* The apparent analogy, however, between these in- A, Plarts of Sphirrnhnfus, natural size. B, magnified view. C, sectional view, with tlie seed just previous to pn jcction. D, the seed in the act of projection. E, a plant immediately after projection ; o, the seed ; b b, a. line indicating its course. * Diet. Cla5sique d'lTist. Nat., Art. Moucites Balistes. The words are ' Insecte a quatre ailes, qui lance ses oeufs a di- verses reprises, et comme par un ressort, lorsqu'on le saisit.* DISPERSION OF SEEDS. 27 sects and tlie plants which disclmrge their seeds, will disappear, when we consider that the scattering of the seeds is, in the plants, a regular and con- stant process of nature; whereas the insects only jet out their eggs fron) fear ivhcn cuu^lit. 'Ihe power of throwing their eggs to a distance, indeed, could be of no possible use to insects, because they pos- sess the more eflicient power of locomotion. The facts which we have thus stated with regard to the seeds of plants being diffused by the means of winged down, or by the more remarkable capacity of being projected, differ, as we have shown, in some important circumstances from the nearly similar ar- rangement of nature in the economy of insects. They constitute atHnities, but not analogies. On the other hand, the n)ore universal law of the conti- nuance of insect lite by every new generation being hatched from eggs, may be illustrated by an analogy, which is observed even in the most minute instances, in the generation of plants from seeds. The ditlusion of the seeds of an extensive order of plants {Crijplou'/rt chloris, Temmixck), ajrain, which builds ail open nest of green moss, lined with horsehair, black or white as it can be had, lays clear white eggs with red spots, precisely like those of the common wren and the willow wren {Sijlria Trocliilus), which build covered nests with a small side-entrance; while the hnuse-sparrow (i'^-jH^i7/« dumcstica) lays eggs of a dull, dirty green, streaked with dull black, and al- ways builds in holes or under cover. These objec- tions will render it unnecessary for us to follow Darwin into his tanciful account of the origin of the colour of eggs, which he ascribes to the colour of the objects amongst which the mother bird chiefly lives acting upon the shell through the medium of the nerves of the eye; for, if this were correct, we should have the green-finch and the red-breast, instead of their white eggs, laying blue ones like the hedge-sparrow and the ■ firetail. Upon a partial view of the subject, we might bring many facts to support the theory from the colour of the eggs of insects. The nettle butterflies, for ex- ami)le, the small tortoise shell ( Vanessa Uriicce), the peacock ( F. /o), and the admirable ( F. Atalanla), all lay eggs of a green colour, precisely sinnlar in tint to the plant to which they are attached. On the contrary, the eggs of the miller moth {Aj)alcla Ltpo- ritut, Steph.), which are deposited on the gray bark of the willow, are light purple; another beautiful geo- metric moth [Gfomtlra illnnarici), which Sepp* calls Hirciilcsje, lays its pink eggs in the fissures of the bark of the elm; the puss moth {Ccrrura I'inula) lavs shining brown eggs on the green leaf of the pop- lar; and the garden white butterfly {Ponfia Brassicce^) lays a group of yellow ones on a green cabliago or cole- wort leaf, but not of so bright a yellow as those of the seven-spot ladybird {Coccinclla Septempimctata)^ * Sepp, der Wonderen Gods, Tab. 35. 3G INSECT TRANSFORMATIONS. patches of which may be found on many sorts of leaves during the summer months. The immediate origin of colour in the eggs of in- sects is in some cases the enclosed yolk shining through the transparent shell; but in others, the shell is not uniformly, transparent, but rmged, banded, or dotted with opacities of various colours. In the eggs of the drinker moth ( Odontsiis jjotaloria), for example, there are two circular rings of a green colour, liom the green yolk appearing through the shell; while the rest of the shell is white and opaque, as we have prov- ed by dissection.* Certain ruddy spots on the white eggs of the small rhinoceros beetle ( Oryctes nasicornisj Iluger) were discovered by Swammerdam to be the red mandibles and spiracles of the unhatched grub seen through the shell; and the white ground, we in- fer, was similarly caused by the body of the grub.f This, however, cannot be the origin of the bright red spots on the beautiful yellow egg of the brimstone moth (Rumia crutiegata., Ddfonchel), which may, perhaps, have a similar origin to those of birds. With respect to the eajgs of birds, it has been re- marked by Mr Knapp,J that in those ' of one hue, the colouring matter resides in the calcareous part ; but where there are markings, these are rather ex- traneous to it than mixed with it. The elegant blue that distinguishes the eggs of the fire-tail ( Sijlvia phoinicurus, Lath.), and of the hedge-sparrow, though corroded away, is not destroyed by muriatic acid. The blue calcareous coating of the thrush's' egg is consumed; but the dark spots, like the markings on the eggs of the yellow-hammer, house- sparrow, magpie, Stc, still preserve their stations on * J. R. t Swammerdam, Book of Nature, i, 13. t Journal of a Naturalist, p. 230. SHELLS OF EGGS. 37 the film, though loosened and rendered mucilaginous by tills rough proci-ss. I'hoiigh this calcareous mat- ter is partly taken up during incubation, the mark- ings upon these eggs remain little injured even to the last, and are almost as strongly defined as when the eggs are first laid. These circumstances seem to im- ply, that the colouring matter on the shells of eggs does not contribute to the various hues of the [)lum- age; but, it is reasonable to conclude, are designed to answer some particular object not obvious to us : for though the marks are so variable, yet the shadings and spottings of one species never wander so as to become exactly figured like those of another family, but preserve year afler year a certain characteristic figuring.' JNIost of these remarks will apply to the colours of the eggs of insects: but though we can in mo.st in- stances trace no connexion between the colours of eggs and the perfect insect, there is a striking ex- ception in the egg of the brimstone moth mentioned above, which corresponds exactly in colour with the wings of the moth, though the caterpillar is of a dull brown. The eggs of insects, like those of birds, have a shell enclosing the germ of the caterpillar with a peculiar matter for its nourishment, like the white and yolk of a bird's egg, provided for the nourish- ment of the contained chick. These several parts, however, are very different in substance from the eggs of birds. The sliell of the bird's egg is brittle, opake, chiefly composed of chalk {carbonate of lime), and lined with a very thin tough membrane; while in the egg; of an insect the shell is not brittle, is transparent, contains no lime (lor it is not per- ceptibly acted upon by diluted sulphuric acid), and no lining membrane can be detected. It appears, indeed, very similar to the transparent portion of a VOL. VI. 4 38 INSECT TRANSFORMATIONS. goose-quill in the eggs of the drinker and other moths which we have dissected;* but in the eggs which are deposited in moist places, and in those ot" spiders, it is extremely thin.y The eggs of saw-flies, ants, &.c, which grow larger, as we shall afterwards show, du- ring the process of hatching, must possess an expansi- ble shell to allow of their enlargement. The yolk and white in the eggs of birds are separated from each other by a very tine membranous bag in which each is contained ; but in the eggs of insects, what an- swers to the yolk consists of distinct minute globules, which float in the white, if we may call it so, for it does not, as we have ascertained, coagulate in boiling water. The eggs of the gypsey moth {Hijpogymna dispar)^ \ which we boiled, still continued partly fluid, though the brown matter answering to the yolk was consider- ably thickened. The portion which does not thicken by boiling most probably forms the first internal fluids of the caterpillar, answering to the blood of quadru- peds. The point where the caterpillar originates, — answering to the scar ( Cicatricula) in the eggs of birds, — we can readily distinguish even by the naked eye in the larger species of eggs, as it lies always immediately under the shell.* ' Having directed,' ' says the younger Huber, ' my close attention to the eggs of ants, I remarked that they were of different sizes, shades, and forms. The smallest were white, opaque, and cylindrical ; the largest, transparent, and slightly arched at both ends ; while those of a middle size were semi-transparent. On holding them up to the light I observed a soj-t of white ob- long cloud; in some, a transparent point might be remarked at the superior extremity ; in others, a clear zone above and underneath the little cloud. The largest presented a single opaque and whitish point * J. R. + Kirby and Spence, Intr. 86. GERM OF EGGS, 39 in their interior. There were some whose whole bo- dy was so remarkably clear as to allow of" my very dis- tinctly obsiM-viiifT tiu- rings. On tixuig attention more closely upon the latter, 1 observed tiie egg open, and the larva appear in its place. Having compared these eggs w ith those just laid, I constantly Ibund the latter ot" a milky whiteness, completely opaque, and smaller by one-half, so that I had no reason to doubt of" the eggs ot" ants receiving a very considerable increase in size; that in elongating they become transparent, but do not at this time disclose the tbrm of the grub, which is always arched.'* The germ in the egg of the garden spider {Epeira di(tdcma) is described by the accurate Ileroldt, as appearing to the eye in form of a minute white point immediately under the shell, and in the centre of the circumterence. On examining this point more nar- rowly, it is found to be of a lenticular shape, and composed of iimumerable whitish granulations of a globular form, diHL'ring only from the globules of the yolk in being smaller and more opaque, as may be seen by s(|ueezing out tlie contents of a s|)ider's egg into a watch-glass. The most singular circumstance observed by Ileroldt was, that in some species ot" spi- ders an egg appeared to have a considerable number dispersed upon ditierent points of the surface; but all these ultimately united into a single germ.^ The eggs of the glow-worm [Lanipiiris noctihica), as we ascertained from those deposited by one which we found in IB'iO, .it Rudesheim, on the Rhine, are golden yellow, somewhat resembling cherry-tree gum, while the internal substance is similar in consistence * M. P. ITuber on Ants, p. fiS. i Heroldt, Exercit. de Cienerat. Aranearum in Ovo, and his Unters. iiber die Bildung der Wizbellosen Tliierc in) Eie. 40 INSECT TRANSFORMATIONS. to the wax of the ears, and in form of granules which are even externally apparent.* We are accustomed to consider the lorm of eggs so nearly regulai- that the epithet ' egg-shaped' is fre- quently applieato other things, and is well understood; hut the eggs of insects, though most commonly round, are seldom, like those of birds, smaller at one end than at the other, while they often exhibit forms never seen in the eggs of birds, — such as cylindric, flat, depressed, compressed, prismatic, angular, square, boat-shaped;| &c. These varieties of form are just- ly referred by Kirby and Spence to the ' manifold wis- dom' {TToXvTToiKiXoi aopici)'^ of thc Crcatorj but we have some hesitation in admitting their limitation of this to his ' will to vary forms, and so to glorify his wisdom, and power independently of other considerations, '§ and think it would be more truly philosophic to con- fess our ignorance where we cannot explain what is above our comprehension. Paley, indeed, says, such facts ' might induce us to believe that variely itself, distinct from every other consideration, was a motive in the mind of the Creator, or with the agents of his will;' but he immediately adds, ' to this great variety in organized life the Deity has given, or perhaps there arises out of it, a corresponding variety of animal ap- petites, and did all animals covet the same element, retreat, or food, it is evident how much fewer could be supplied and accomn)odatcd, than what at present live conveniently together, and find a plentiful subsistence. '|| The latter remark, v.^e think, completely destroys the former, and it will lead us to what appears to be * J. R. t Dumeril, Consider. G>'n rales, p. 49; ami Insect Archi- tecture, p. 19. t Ephes. iii, 10. § Introd. iii, p. 95. II JNatuial Theology, p. 345, 14th ed. FORMS OF EGGS. 41 the true^ cause of the varied forms of tlic eggs of in- sects. ig'i The cause of the eggs of l)irds being nearly tiie same in sliape, arises, we should say, Ironi the similar forms of the animals themselves; while insects being much more varied in shape, require corresponding varieties in the torms of their eggs. The ostrich, the eagle, and the wren, for example, differ much more in size than in their general form; but the earwig, the garden-spider, butterflies, beetles, and grasshoppers, differ much more in form than in size, and consequently require eggs of varying forms to contain their progeny. We confess, however, that we cannot always trace the mathematical causes of these diversities of form in the eggs of insects; for though there prevails a general resemblance in those families and groups the most nearly allied, yet in others, even the species of the same genus exhibit differences which cannot be thus accounted for. In two species of Vanessa, for instance, the small and the great tortoise-shell butterflies, which differ in little but size, the egg of the small is cylindric with eight prominent ribs, while that of the great is shap- ed like a Florence flask, and quite smooth and uni- form.* The ribbing of the eggs of the small tortoise-shell * Sepp, der Wonderen Gods, Tab. ii, and viii. VOL. VI. 4* 42 INSECT TRANSFORMATIONS. butterfly (Vanessa iitirccB) , which is also found on those of most of the species, leads us to remark that insect eggs are frequently sculptured in a very beau- tiful manner, far out-rivalling in elegance of design and delicacy of workmanship the engravings which we sometimes see on eggs brought from India and China. Some of them, when seen through a micro- scope, remind us of the fine crustaceous shells called sea-eggs, — a resemblance which is well exemplified in the egg of the angle-shades moth [Phlo2;opliora meticulosa, Stephens), as compared with the Chj- peaster of Parkinson. <-, — „ „, - - e angle- shades iiuitli C P/i/(,:,'(//»Ao/y/ vitti- cutosu) ; I, seii-eg^' (Ctyptasttr,) iialural size. These channellings appear to correspond in most cases with the rings of the caterpillar to be hatched from the egg; but the design of tlie other sculptures on these eggs has not yet been discovered hy the investigations of naturalists, and may, probably, for ever elude human penetration. But though we cannot tell why an insect's egg is so tastefully carved, we can admire the minute delicacy and extraordinary regularity of the markings. The egg of the meadow brown butterfly {Hippnrchia Jurlina) is crowned at the upper end with sculptured work in the form of tiles or slates, as if to defend it from injury, while others are covered with a sort of net-work of extreme- ly minute six-sided meshss. FOnMS OF EGGS. 43 of Ihe biiiii.stoiie-iiuilli ( li ,-lMUUvll>, MKifiiilinl; /,, egg « C,ut,iub3 hiunniiig cocoons, f, grubs eating their wa> out ol the caterpilldi PARASITE INSECTS. 63 But it is not only in the nests of bees and wasps, or in the bodies of caterpillars, that these provident mo- thers contrive to depc^it their e(iund near Wandsworth, attached to the stem of a rush growing in water. There was a deposition of eggs at the bottom, the rest of the space being vacant. De Geer describes * J. R. 94 INSECT TRANSFORMATIONS. similar spiders' nests attached to the stems of grass;* and we once found a large one of an elongated shape, and composed of very white silk, on a sp.ke of grass at Compton-Basset; Wiltshire.! Spiders' nests. The vapourer ( Orgyia antiqua, Ochsenh.), a com- mon moth, takes advantage of the warm silken enve- lope of the pupa-case, from which she has escaped a few days before, to form a bed for her eggs. In our earlier studies of insect economy we were inclined to ascribe to accident the deposition of the eggs in this particular situation, but we have found so many in- stances of it as to reject the explanation. Swammer- dam also observes, that ' this custom of fastening the eggs to the web in a constant method, and by the immutable law of nature, is so peculiar to this species of insects, that I have never obser- ved it in any other kind whatsoever. This fe- male,' he subjoins, ' like a most prudent house- wife, never leaves her habitation, but is always fixing her eggs to the surface of the web out of which she has hei-self crept, thus affording a beau- tiful instance of industrious housewifery. 'J One De Geer, Mem., vol. vii, pp. 227 — 9. ^ Swammerdam, pt ii, page 7. t J. R. DEPOSITIONS OF EGGS. 95 reason for this is, that the female of this moth having only the rudiments of wings, a peculiarity remarkable in several other moths, she cannot shift so readily about. But whatever may be tlip real cause, there can be no doubt that tlie web serves to keep the eggs Warm during winter; for though they arc placed on the outside of the web, the \\ hole is usually under some projection of a wall or arm of a tree, and the non-conducting property of the silk, both with regard to heat and electricity, must be of great benefit to the eggs in preserving them in an equable temperature, and of course promoting their early hatching. I: I J ■ t ;/ \j/ - - - Vnpoiirer Molh (Or^jia antiqtw), male and female, ilie latter ■wilhoi:t wings ; with the eggs laid upon the silken cocoon froni which the moilier has issued. We cannot better conclude these imperfect sketches of the hybernation of insect eggs, than by an ac- count of the ingenious experiments made by Spal- lanzani and John Hunter, by exposing several spe- cies of these to great degrees of cold as well as of heat. It results from these experiments that ' intense cold,' to use the words of Spallanzani, ' does not destroy the eggs of insects. The year 1709, when Fahrenheit's thermometer fell to 1°, is celebrated tor its rigour and its fatal effects on plants and animals. Who can believe, exclaims Boerhaave, that the severity of this winter did not destroy the eggs of insects, especially those exposed to its influence in the open fields, on the naked 96 INSECT TRANSFORM VTIONS. earth, or or on the branches of trees ? Yet, when the spring had tempered the air, these eggs produced as they usually did after the mildest winters. Since that period there have been winters more severe. In France, during December, 1788, the thermometer fell considerably lower, and in several other tempe- rate European climates. ' I have exposed eggs to a more rigorous trial than the winter of 1709. Those of several insects, and among others the silk-worm, moth, and elm butterfly [Vanessa polychloros .^) were enclosed in a glass vessel and buried five hours in a mixture of ice and sal gem {rock salt); the thermometer fell 6° below zero. In the middle of the following spring, however, caterpillars came from all the eggs, and at the same time as from those that had suffered no cold. In the following year, I submitted them to an experiment still more hazardous. A mixture of ice and sal gem with the fuming spirit of nitre {JVifrate of Ammonia), reduced the thermometer 22° below zero, that is 23° lower than the cold of 1709. They were not injured, as I had evident proof by their being hatched. ' Combining all these facts, we conclude that cold is less noxious to germs and eggs, than to animalcula and insects. Germs iu general can support 2° be- low zero; whereas of animalcula some die at the freezing point, and some at about 20°. The eggs of many insects continue fertile after being subjected to a temperature of 22° below zero, while insects themselves die at 16° and 14°. This I have ascer- tained in the eggs of the silk-worm moth and of the elm butterfly, and although there arc caterpillars and chrysalides able to resist great cold, I have uni- formly found it to be in a less degree than what can be resisted by their eggs. What can be the cause of so great a diircrencc.^ Insects killed at 16° and 14° EFFECTS OF COLD UPON EGGS. 97 are so penetrated and frozen by the cold, that their members do not yield to the pressure of the finger, and seem perl'eet ice under the knife. This does not happen to eggs, though subjected to cold of much greater intensity. Their contents remain fluid, even at the greatest cold, as may be seen by crushing them with the nail. Perhaps this is derived from constitu- ent spirituous or oleaginous parts, or from some prin- ci[)le adapted to abate the power of cold.* If eggs do not freeze, it is probable the included embryos do not freeze. Is there anything wonderful, therefore, that they then survive cold which is fatal to them when produced ? Probably for the same reason (and I see no objection that can apply), animalcula, con- centrated in the germ, can support a degree of cold they arc uicapable of when developed. ' As the temperature of freezing still retains a portimi of heat, why, it may be asked, should it not develope the germs of the most minute animalcula? Had we never seen any eggs hatched but those of birds, which require 104°, we should have concluded that all others require the same. A little initiation into the study of minute animals teaches how many kinds produce at a temperature infinitely less. Such are the eggs of butterliies and many otlier insects, of frogs, lizards, tortoises, down to some, as those of toads, which I have seen produce at 45°. If these eggs hatch at 59° less than is required by those of birds, what repugnance will there be to suppose that at 13° less, or the freezing point, the eggs of other animals may be hatched ^ JVor should it surprise me to be told of animals whose eggs would produce at much greater cold, after knowing that there are plants, beings so similar to animals, and many of them, * In plain language, Spallanzani did not know what to make of the facts. 9 98 INSECT TRANSFORMATIONS, which amidst the rigours of winter flourish and fruc- tify.'* It is remarked by John Hunter that an egg will freeze by a great degree of cold; at the same time there seems to be a living principle which enables it to support cold without destruction, and when once that principle is destroyed, cold more easily operates. An egg was thus frozen by the cold of zero; aller thaw- ing and again exposing it to the same degree of cold, it froze seven minutes and a half sooner. A new-laid egg took an hour to freeze in 15° and 17°, but when thawed, it froze at 25° in half the time.t The principle of vitality, therefore, whatever may be the cause, is evidently less easily destroyed in the egg- state than in the perfect animal; and therefore the inference that a rigorous winter promises a diminution of insects in the summer succeeding commonly proves erroneous. On the contrary, recorded facts prove that they are sometimes even more abundant than usual after severe frosts. During the present spring of 1830, accordingly, notwithstanding the severe frosts of the preceding winter, we have observed a much greater number of insects, even of the smaller and more delicate kinds (^'Heyrodes, Corcihra, Alucita^ &c,) as well as of larvae, both those just hatched, and those which have lived through the winter, than last year, when the frost was not so severe. We were particularly struck witli the larvte of some small tipula {Boktophila}), which we found in abundance in Birch Wood, Kent, feeding on a fungus {Boletus fomentarius, Fries), and which were so beautifully transparent and soft, that we could not understand how they had escaped being frozen. It is not a httle remarkable, in connexion with this, that the * Spallanzani's Tracts, transl. by Dalyell, vol. t Hunter ou the Animal Economy. EFFECTS OF COLD UPON INSECTS. 99 migratory birds seem to have been aware of this abun- dance ot" insects by their ap|)cariii. 106 INSECT TRANSFORMATIONS. in triumph. The spider, however, instantly regained it with her mandibles, and redoubled her endeavours to snatch the bag tiom her enemy ; but her efforts were vain, for the ant-lion, being the stronger, suc- ceeded in dragging it under the sand. The unlbrtu- nate mother, now robbed other eggs, might have at least saved her own life, as she could easily have escaped out of the pit-fall ; but, wonderful to tell, she chose rather to be buried alive along with her eggs. As the sand concealed from my view what was passing below, I laid hold of the spider, leaving the bag in the power of the ant-lion. But the affectionate mother, de- prived of her bag, would not quit the spot where she had lost them, though I repeatedly pushed her with a twig. Life itself seemed to have become a burden to her since all her hopes and pleasures were gone for ever.'* That some portion of heat may bo communicated to the eggs of the spider, which are thus carried so assiduously under her body, is highly probable ; and it is also, no doubt, advantageous to the young, when hatched, to have the assistance of their mother to open the bag for them, as was remarked by De Geer;"!" ' without which,' says Kirby and Spence, ' they could never escape. 'J But that neither of these are indispensable conditions we have ascertained by re- peated experiments. We have taken u considerable number of these egg-bags from their mothers, and put them under inverted wine-glasses and into pill- boxes, and in every instance the young have been duly hatched, and made their way icithoiit assistance out of the bag. In all these cxperinjents, the young spiders joined in concert in making a web across their prison ; a circumstance at variance with the assertion * Bonnet, CEuvres, vol. ii, p. 435. t De ficer, Mem. vol. vii, p. 194. t InUod. i, p. 361. HATCHING OF EGGS. 107 copied from Lister into most subsequent works on natural history, that this species never spins a web. They might not indeed have done so if tliey had been left at hberty.* A spider of tJje same species, which Bonnet kept under an inverted glass, at first was so exceedingly- attached to her bag of eggs, that he could not beat her away from it after it was detached. ' By and by,' he continues, ' I observed with surprise that she had abandoned and kept aloof from the very bag M'hich slie had previously defended with so much cou- rage and address; and I marvelled still more to see her run away from it when I placed it near her. I remarked at the same time that she had become less agile, seemingly in consequence of sickness. By more close observation, I discovered that several of the young ones were hatched, and their numbers increased by degrees, while all ran towards their mother and climbed upon her body. Some placed themselves on her back, some on her head, and some on her limbs, so that she was literally covered with them, and appeared to bend under the weight, not so much from being over-loaded, as from her teeble con- dition ; and indeed she soon afterwards died. The young spiders remained in a group upon the body of their mother, which they did not abandon for some time, and for the purpose, as I was half inclined (pardon the odious supposition) to think, of sucking the juices of her body.'f In order to prove whether a spider of this species could distinguish her own egg-bag from that of a stranger, we interchanged the bags of two individuals, which we had put under inverted wine-glasses ; but both manifested great uneasiness, and would not touch the strange bags. We then introduced one of the mothers into the glass containing her eggs and the * J. R. t Bonnet, Gi^uvres, vol. ii, p. 440. 108 INSECT TRANSFORMATIONS. other spicier; but even then she did not take to them, which Ave attributed to the presence of the other, as all spiders nourish mutual enmity. Upon removing the stranger, however, she showed the same indifTer- ence to her eggs as before, and we concluded that, after having lost sight of them for a short time, she was no longer able to recognize them.* A more extraordinary method of hatching eggs oc- curs in several insects, thence termed ovo-vivi parous, which retain the eggs within their bodies till they are hatched; and in this way they appear, like larger ani- mals, to produce young instead of eggs. We do not here allude to the cochenille insects Ibrmerly mention- ed; for though these cover their eggs with their bodies, it is after they are laid and imbedded in gos- samer. Neither can these suigular insects be proper- ly said to sit upon their eggs, inasmuch as the mother always dies when she has tinished laying. The guffer {Bknnius ovo-riviparus, Lacepede), a British sea-fish, common under stones at low-water mark, affords an instance of this singular mode of the eggs being hatched in the body of the mother; and it is remarkable that when the young are ready to appear, she leaves her usual haunts on the coast, and goes farther out to sea, that they may be out of the reach of their natural enemies. "f Our common viper (^Coluber berus, Linn.) is also ovo-viviparous, as are several other reptiles; though it is an exception to the general rule in this class. We caught a female of the nimble lizard {Laccrta agUis, Linn.) on a heath near Sorn, Ayrshire, in July, and kept it for some time under a glass, where it produced six young ones; but in consequence of improper food, or of confinement, they all soon died.| This lizard is said to be some- times oviparous. The observations also of the elder * J. R. t Lacep?de, Toissong, ii, p. 1S7. t J. R. OVO-VIVJPAROUS INSECTS. 109 naturalists with respect to the scorpion's being ovo- vivi|)arous, have l)een recently verified by Leon Duti)ur,* a living French naturalist, distinguished for acuteness and accuracy. In the case of insects, it was first discovered by Redi, the father of experimental entomology, that, though the greater number of flies lay eggs, some also bring forth their young alive; and he was thence led to put the question, wiiether such flies, under dif- ferent circumstances of temperature, do not sometimes produce young, and at other times deposit eggs."f He might as well, says R aumur, have asked whether, in certain circuujstances, a hen, instead of laying eggs, should bring forth chickens. The fact, on the contrary, has been ascertained by R aumur, and re- cently confirmed by .Dufour,;}; that the ovo-viviparous insects are furnished with an abdominal pouch, in which the eggs are deposited by the mother previous to their" being hatched. In this respect they afford a striliing analogy with the kangaroo, the opossum, and other inarsu|)ial quadrupeds, which are furnished with a simi- lar pouch for protecting their young in the first stage of their existence. One of our most common flies exemplifies this. It may not have occurred to many of our readers that there are more sorts than one of the large flies usually called blow-flies and flesh-flies. One of these, distinguished by its brilliant shining green colour and black legs {jMiisca Ccvsar, Li.\,\.), we have adverted to^ in recounting the experiments of Redi; another, frequently called the blue-bottle (JMitsca vomiforiay Li.NN.), is easily distinguished by the abdomen being of a shining blue, the shoulders black, and the forehead fox-coloured. The insect, however, to which we wish to call attention at present, though nearly the size of the * Noiiv. Diet. dTIist. Nat., xxx, 426. + Redi, Espeiienze iiitorno alia Gen degl' Insetti, 4to, 166S. t Annales des Sciences IS'aturelles. § Page 3. VOL. VI. 10 110 INSECT TRANSFORMATIONS. blue -bottle, rather longer and more slender, and black, with lighter stripes on the shoulders, is not blue in the abdomen, but grayish black, and all over chequered with squares of a lighter colour. This chequered blow- fly {Scnxophaga carnaria, Meigen) does not even belong to the same genus as the preceding, and differs from it in the remarkable circumstance of hatching its eggs in an abdominal pouch, and instead of eggs depositing maggots upon dead carcasses. The eggs of all the flesh flies are in sultry weather hatched with great rapidity; but in the case of the chequered blow- fly, nature has provided the means of still more rapid destruction for removing the oflensive parts of carcasses. The arrangement of the numerous minute larvae in the pouch is very remarkable, and resemi>les the coil of a watch-spring or a roll of ribbon. R aumur had the patience and perseverance to uncoil this multitudinous assemblage of flies in embryo, and found it about two inches and a half in length, though the body of the mother-fly herself was only about one-third of an inch, A itie chequered blowfly. B, tlie nlxloineii nf the cluniiifi blow-fly, opeiitnl and mngnificd, showing tli« coil or\oiuii; liii> C, th« eoil of Jarvie pertly unwound. OVO-VIVirAROUS INSECTS. Ill and he computed that there were al)out 20,000 young in the coil.* When this extraordinary fecundity is considered, we need not wonder at the countless swarms which appear as if by magic upon a jcint of meat du- ring hot weather. Like most female insects, the mother-fly dies in a few days after giving birth to her numerous brood; but, unlike the oviparous flies, she seems to take a considerable time to deposit the whole. It would be impossible indeed for her pouch to contain the larvae if they were all hatched at the same time; and there- fore it has been so ordered by Providence that they should arrive at maturity in succession. From the early death of the mother, R aumur conjectured that they did not scruple to eat their way through her bowels; but he disproved his supposition by a most decisive experiment. He took a fly wiiich had already deposited a few larv.e, and closed the natural opening of the pouch with sealing-wax, so that it was impossi- ble any more could make their exit there. The mother lived several days longer than she would have done, had she been left at liberty to produce her young; but not one of them attempted to force a passage, after being shut up tor ten days. Another large gray fly withi)rick-red eyes (species A A, large gray blow-fly, with the nhdonien opened, showing the young maggols. B, breathing apparatus of the maggot of a large gray blow- fly. Reaumur, INIeni. iv, 41' 112 INSECT TRANSFORMATIONS. not ascertained) was discovered by R'ainnur to be ovo- viviparous; but the embryo flies were not arranged in the jwvich in the same spiral tbrm as the preceding, but longitudinally. These did not appear to be quite so numerous; and they had a peculiar breathing appara- tus, which, when shut, as it could be at pleasure, ap- peared in the form of a crown. Amongst several other ovo-viviparous flics discovered by R'aumur, there was a very minute tipulidan gnat (species not ascertained) with a jet-black body, white wings, and beaded antennce, not larger than the head of an ordinary pin, which was bred in great numbers from some cows' dung put into one of his nurse-bo.xes for another purpose. He justly remarks upon this cir- cumstance, that 'the minute and the grand are nothing, or rather are the same, to the Author of nature.' The numerous genus Aphis presents the singular anomaly of producinjT eggs in the autumn and living young during summer, and, as Curtis tells us, even during winter in green-houses. De Geer, however, ascertained that it was not the same individual aphides which at one season produced young and at another eggs, but different 2;enei-alions.* By a series of very careful and troublesome experiments Bonnet also ascer- tained the curious fact^that in three months nine gene- rations of these insects may be produced in succes- sion, though the males be rigorously excluded from the nurse-boxes where the females are isolated. In fact all the aphides produced in spring from the eggs laid in autumn appear to be females; and no males are pro- duced till the end of summer, a short time before the eggs are deposited for winter. Among both males and females are some with and some without wings, — the nature of which distinction does not appear to be yet ascertained. * Ue Geer, Mem. des Insectes, iii, 70. EGGS GF APHIDES. 1 13 Bonnet, however, whose opinion is entitled to considerable authority, seems to think tliat the egys of aphides which are destined to snr\ ive tlie winter are very dilFerent from other eggs; and he snj)poses that tlie insect, in a state nearly perfect, quits the body of its mother in that covering which shelters it from the cold in winter, and that it is not, as other germs are in the egg, surrounded by f<)od, by means of which it is de- veloped and supported. It is nothing more, he con- jectures, than an asylum of which the aphides ap- pearing at another season have no need ; and it is tor this reason that some are produced naked and others enveloped in a covering. If this be correct, the mo- thers are not then truly oviparous, even in autumn, when they deposit these pseudo-eggs; since their young are almost as perfect as they ever will be, in the asy- lum in which they are naturally placed at birth. It was in vain that Bonnet endeavoured to preserve eggs of this sort in his chamber till spring, in conse- qut nee, he imagines, of the want of a certain degree of moisture which they would have had out of doors We have been more successful, through the precaution of not taking the eggs from their native tree till Feb- ruary, and in 18.30 we had a brood of several hundreds produced of the oak aphis (^Jlphis Qnercus),* The failure on the part of Bonnet leads us to re- mark, with the younger Huber, that ants are more skilful in this respect than naturalists, and an.\iously nurse, during winter, tbe eggs of aphides, which they collect with great care in the autumn. The interest- ing narrative of the discovery of this we shall give in Ruber's own words. ' One day in November,' says he, ' anxious to know if the yellow ants [Foriuica flava) began to bury themselves in their subterranean chambers, I dtJ-> stroyed, with care, one of their habitations, story by * .T. R. vor.. VI. 10* 114 INSECT TRANSrOR3rATIONS. story. I had not advanced far in this attempt, when I discovered an apartment containing an assemblage of little eggs, which '.vere for the most part of the colour of ebony. Several ants surrounded and ap- peared to take great care of them, and endravoured, as quickly as possible, to convey them from my sight. I seized upon this chamber, its inhabitants, and the treasure it contained. ' The ants did not abandon these eggs to make their escape; a stronger instinct retained them: they hastened to conceal them under the small dwelling which I held in my hand, and when I reached home, I drew them from it, to observe them more attentively. Viewed with a microscope, they appeared nearly of the form of ants' eggs, but their colour was entirely different; the greater part were black; others were of a cloudy yellow. I found them in several ant-hills, and obtained them of different degrees in shade; they were not all black and yellow; some were brown, of a slight and also of a brilliant red and white; others were of a colour less distinct, as straw colour, grayish, and I remarked that they were not the same colour at both extremities. ' To observe them more closely, I placed them in the corner of a box faced with glass; they were col- lected in a heap like the eggs of ants; their guardians seemed to value them highly; after having visited them, they placed one part in the earth, but I witnessed the attention they bestowed upon the rest; they approach- ed them, slightly separating their mandibles; passed their tongue l)etween each, extended them, then walk- ed alternately mer them, depositing, I believe, a liquid substance as they proceeded. They appeared to treat them exactly as if tliey were eggs of their own species; they touched them with their antennae, and frequently carried them in their mouths; they did not quit these eggs a single instant; they took them CARE BT ANTS OF EGGS OF AnilDES. 115 up, turned them, and after having surveyed them with atTt'ctionate regard, conveyed them with extreme tenderness to the little chamher of earth 1 had placed at tlieir disposal. They were not, however, the eggs of ants; we know that those are extremely white, be- coming transparent as they increase in age, but never acquire a colour esseiitiully dillerent. I was, for a long time, unacquainted with the origin of those of which I have just spoken, and by chance discovered they contained little aphides; but it was not these in- dividual eggs I saw them quit; it was other eggs which were a little larger, lound in the nests of yellow ants, and of a |)articular species. On opening an ant- hill, 1 discovered several chambers containing a great number of brown eggs, of which the ants were ex- tremely jealous, carrying them with the utmost expe- dition to the bottom of the nest, disputing and con- tending for them with a zeal which lett me no doubt of the strong attachment with wliich they regard them. ' Desirous of conciliating their interests, as well as my own, I took the ants and their treasure, and placed them in such a manner that I might easily observe them. These eggs were never abandoned. The ants took the same care of them as the former. The fol- lowing day I saw one of these eggs open, and an aphis fully formed, having a large trunk, quit it. I knew it to be a puceron of the oak: the others were disclosed a few davs after, and the greater number in my presence. They set immediately about sucking the juice from some branches of the tree I gave them, and the ants now lound, within their reach, a recom- pense for their care and attention. The ant-hill whence these eggs had been taken was situated at the foot of an oak, which readily accounts for their existence in that place. I discovered them in the spring; the pu- cerons which quitted them were very large tor insects 116 INSECT TRANSFORMATIONS. just born, but they had not yet obtained their full size.'* It is not, however, the aphides themselves who select the snug winter retreat of an ant-hill, or who know how to secure the careful nursing of the ants. All this is the s dIc concern of the latter, to secure for them- selves a supply of the honey-dew, as it is erroneously called, secreted by the aphides in spring. The ants, it may be proper to remark, take similar care of their own eggs (as well as of their cocoons, popularly sup- posed to be their eggs) as was remarked by Sir E. King, in the reign of Charles II. He informs us that they diligently gather together in a heap their true eggs, which are small and white like the granules of lump sugar, and upon these eggs they lie in multi- tudes, * [ suppose,' says Derham, ' by way of in- cubation.'| ' I have observed,' adds Sir E. King, ' in summer, that in the morning they bring up those of their young called ant -eggs [cocoons) towards the top of the bank, so that you may, from ten o'clock till five or six in the afternoon, find them near the top, — for the most part on the south side. But towards seven or eight at night, if it be cool, or likely to rain, vou may dig a foot deep before you can find them. 'J An interesting fan)ily of two-winged flies {-Hip- poboscidce, Leach) resemble the aphides in some points of their economy, though in others they are singularly peculiar. R aumur discovered, what has been recently confirmed by Dufour and others, that the mothers not only hatch their eggs within the body, but retain them there till they are changed into chry- salides. R aumur gives a lively narrative of his discovery, and the solicitude of his servants to find him female flies ready to deposit what he at first took for ♦ IVf. P. ITuber on Ants, p. 245. + Derham, I'hys. Theol. ii, 207. 11th ed, t Phil. Trans. No. xxiii. OVO-VIVIPAROUS FLIES. 117 eggs. He was so anxious to hatch those supposed eggs that he carried I hem in his pocket hy day and took tlicm to bod with him at night, (as JJonuet after- wards did with the eggs of aphides,) f<)r several weeks successively; but instead of grubs, as he had expected, perfect flies were evolved exactly similar to their pa- rents. He calls them spider flics, from their resem- blance to spiders; and in some parts of France the species which infests horses {Hippobosca equina) is called the Spaniard or J3r«ton: in England it is too well known under the name of the forest fly. Spider flies {Hippoboscidcr, Leach.) We have the more willingly introduced this sub- ject here, that another fly [Crativina Hiriiiulinis, Oi.FERs), of the same family, has the instinct to de- posit its egg-like cocoons in the warm feathery nest of swallows, where they have all the necessary heat which R aumur, in his experiments, was so careful to maintain. In return l<)r the warmth which the voung has thus received, the perlect fly, during its brief ex- istence, lives by sucking the bluod of the swallows, as the one first mentioned sucks the blood of horses, horned cattle, and, it is also said, of man. 118 INSECT TRANSFORMATIONS. The effect of heat upon the eggs of insects has been carried much farther than in the experiments just alluded to of R aumur and Bonnet.* Spallanzani was desirous of ascertaining what degree of heat the eggs of insects and other animals, as well as the seeds of plants, would bear when compared with their larvae ; and he found that below 93° Fahr. silk-worms did not appear atfected, but at 95°, and still more at 97°, they became restless, while at 99° they ceased to move, and all died at 108°. The eggs of these, on the other hand, long resisted the inlluence of heat. At 80° they were the most productive; at 99° many still appeared, but with considerable diminution, and as the heat was increased their fertility decreased, till at 144° not one was tertile. The eggs and caterpillars of the elm butterfly {Vanessa polijcliloros'?) perfectly corresponded with those of the silk-worm. In the case of the eggs of the blow-fly {Musca vomitoria) a great many produced maggots at 124°; but at 135° and 138° very few, and all were sterile at 140°. The maggots produced from these eggs became restless at 88°, and endeavoured to escape, and as this heat was increased they became proportionably more agitated till it arose to 108°, when they all perished. Full- grown maggots of the same kind all died at 108°; but when changed into flies they died when the heat was so low as 99°; though their piipae were produc- tive at 104° and 106°, but not at 11 l°.t If these experiments may, as we believe they may, be relied on, we have some reason to doubt that ' the eggs of the musca vomUoria, our common blow-fly, are often,' as Dr Good affirms, ' deposited in the heat of summer upon putrescent meat, and broiled with such meat over agndiron in the form of stakes, in a heat not merely of 212°, but of three or four times 212°; and yet, instead of being hereby destroyed, we * See Insect Architecture, p. 24. t Spallanzani, Tracts by Dalyell, vol. i, p. 35. EFFECTS OF JIEAT UPON EGGS. 119 sometimes find them quickened by this very exposure into their larva or grub state.'* It would have been well if some more accurate authority had been given for so miraculous a fact than this general statement: the appearance ot" maggots on broiled meat, from which the inierence is apparently made, seems ratlier to indicate that eggs, or more probably ovo-viviparous larvte, had been deposited there, not btfori'y but ajhr the broiling. One certain result of all s;uch experiments is, that eggs are mure capable of withstanding heat than the animals producing them; and from similar experi- ments the same law appears to hold with the seeds of plants, which also withstand more heat than eggs. Water increases the destructive influence of heat. The causes upon which these curious facts depend do not appear to be well understood It is certain, however, that the life of an animal in the egg is feeble, or at least lethargic, in comparison with that of the animal produced ; and that animals, when in a state of very feeble animation, resist external injuries with more impunity than when very vivacious. We once saw a vcrv delicate young girl, emaciated with scro- fula, have her leg amputated without even heaving a sigh; while a robust Irish labourer, who underwent the san)e operation immediately after her, roared like a bull. Experiments prove that the fluids of eggs, and con- sequently of their germs, are more abundant tban in vegetable seeds; and this excess of fluid may tend to destroy the germ more readily, from heat expanding the fluids, and thus putting theni in motion: for then they must strike violently against the tender parts of the germs, and rupture and destroy them. Hence seeds exposed to heat arc killed at lower degrees in water, than if dry, in the same way as ice will melt sooner in warm water than in air of equjd temperature.f * Good's Book of Nature, vol. i, p. 221. 1st edit, t Spallanzani, Tracts by Daljell, vol. i, p. 43. 120 INSECT TRANSFORMATIONS, In the practical management of the eggs of the silk- worm, Count Dandolo directs the temperatLiie of the stove-room to be 64° wlien they are first put in. ' The third day the temperature should be raised to 66°; the fourth day to 68°; the fifth day to 71°; the sixth day to 73°; the seventh day to 75°; the eighth day to 77°; the ninth day to 80°; the tenth, eleventh, and twelfth days to 82°. When the temperature of the stove-room is raised to 75°, it is advantageous to have two dishes, in which water may be poured, so as to offer a surface of nearly four inclies diameter. In four days there will have taken place an evaporation of nearly twelve ounces of water; the vapour, which rises very slowly, moderates the dryness which might occur in the stove-house, particul.trly during a north- erly wind: very dry air is not favourable to the devel- opment of the silk-worm.'* Damp or stagnant air, or sudden changes of temperature, either high or low, are exceedingly injurious to the hatching of eggs. From some very curious experiments of Michelotti, it appears that exposure to light is by no means favour- able to the hatching of eggs This ingenious natural- ist i iclosed a number of eggs in glass vessels, admit- ting the light to one series and excluding it from another, similar in every other particular. The result was, that few or none of the eggs exposed to light were hatched, while those in the dark were almost all fertile. He arrived at the same results in his experi- ments upon vegetable seeds. "f Kirby and Spence justly remark, that these curious facts may account for so many insects fastening their eggs to the under sides of leaves, and may be the final cause of the opaque horny texture of those exposed in full day. J Among the singular circumstances in which insects differ from the larger animals, we may reckon that ♦ Count Dandolo, on Silk- Worms, Eng. trans., p. 55. t Philosophical Mag., vol. ix, p. 244. :f Intiodac. iii, p. 77. INCREASE IN SIZE OF EGGS. 121 of the eggs of some increasing in size during the pro- cess ol' liiitcliing. 1 he lact ii[pears to have first been not iced by the celc l)ruted Valhsnieri in his observa- tions on saw-liies {Ti)ithn(Hni(Uv, Leach).* Other instances were subsequently discovered by R'aumur, De Geer, Derhani, R sel, and the younger Huber, ' It oirght not,' says R auinur, speaking of gall flies {Cijiiipiila', Westwood), 'to be passed in silence, that the vgfr which I found in the gall appeared to me considerably larger than the eggs of the same spe- cies when they prcceed from the body of the fly, or even w hen tluv are taken from the mother fly near the time of their being laid. The whole of those 1 took from the mother flies which I killed were remarkably 1*. ==«^ Generation of a water-mite (Hijrlrit'hna nbstcr^ens). a o, the wnler scoipion, in vlii'se liody the mite fives her epgs. 6 i, a mapniOed view ol one of its claws. .-, a tioth-hke l^roce^s for restrainii g the motion ol the joint, rf, the watei mite. <, a greatly magnified view i,f one of iL> eggs. /, the hook by which it is iuseited into the body of the scorpion. * See Insect Architecture, pp. 157-8. VI. 11 122 INSECT TRANSFORMATIONS. small; and I thence inferred that the eg-r would have, and indeed had, increased in the gall.'* R sel made a similar observation on the red eggs of a water-mite [Hijdraclina abster2;ens)\ and he was induced to suppose (justly, as we think) that, as they are deposited upon the bodies of water-scorpions {JS^dpidcB, Leach), they derive their means of in- crease from tliem.t De Geer remarked that the water-scorpions, when much infested with them, be- came gradually weakened as the eggs increased in size. J Huber the younger, in the cotu'se of his experi ments, discovered that the eggs of ants, from being small and opaque, became comparatively large and transparent. ' To be convinced of the truth of this,' he says, ' I viewed those eggs with the microscope. I also measured them, and having separated them from each other, found the longest to be those only in which the grubs were hatched in my presence. If I removed them from the workers, before they attained their full length and transparency, they dried up, and the grubs never quitted them.' Huber is inchned to attribute this remarkable increase and transparency to the humidity imparted to them by the working ants who so assiduously pass them through their mouths. ' For,' he adds, ' if they be not sur- rounded with a liquid, or preserved from the influence of the external air, their pellicle, moistened every instant by the workers, may preserve a certain degree of suppleness and expansibility, according to the de- velopment of the included grub.'^ The most minute observations, however, of this kind, which have hitherto been pi'blished, were made * R auiTiur, Mem. vol. iii, p. 479. ■t R sel, Insecten, vol. iii, p. 152. t De Geer, Mem. des Insectps, vol. vii, p. 145, § M, P. Huber on Ants, p. 72. DEVELOPMENT OF EGGS. 123 by HerokU on the cp-gs of the jiarden spider (Epeira (iKuloua), to which we ronncilv alhidc d. He divides the |)i()cess of iiatehiiig into twelve periods, according to th(! profjiess of development. This progress is not measured by time, as has been done in experiment- ing on the eggs of birds. The germ, or cieatricula, \vhich is composed of minute granules, when jilaced in a due temperature, begins to expand towaids the e.\tremity of the egg, till it takes the form of a comet, whose nucleu.-^ is the centre of the germ, and whose tail* consists of transparent globules. On continuing to expand, or rather to dis[)erse its grannies, they appear to be decomposed into imperceptible mole- cules, producing a sort of translucent clond, through which the globules of the yolk may be distinguished. The place which the germ previously occupied ap- • pears as a single transparent point. The cloudy matter next aecumidatf s round the centre of the germ, assumes a pearly aspect, and becomes solid and 0|)aqae. This is the rudiment of the embryo spider, the outline of whose head and body becomes appa- rent, occnpying a little more than a fourth of the tgg. At first this embryo appears homegeneous, but by and by four little archlets are seen, which are the rudi- ments of the legs, and at the same time the outlines of the mandibles are termed. The whole secns to derive nourishment from the yolk, in which it is rooted as a parasite plant upon a tree. When the embryo spider is near its exclusion, it completely fills the inte- rior of the egg, the shell of which moulds itself close- ly around the body, and it looks like the nymph of a beetle.* When sufficiently developed, it makes a rent in the shell, as was first observed by De Gecr, oppo- site the breast, through which it pushes its head, and successively disengages its body; but the shell still envelopes the legs and feet, and it is not without a * Heroldt, Exercit. de Geuer. Aranearum in Ovo. 124 INSECT TRANSFORMATIONS. great deal of trouble, by alternately stretching out and contracting them, that it succeeds in rending this, and sets itself at liberty.* Even then the youtjg spidtM- can neither spin a web nor catch piey; for it is still en- veloped in an extremely delicate membrane, which it does not moult unless the weather is tavourable and fine.t Hatching of the egg of the garden spider (Epcira dindcma). a, natural size. 6, egg magnified, the cii atriciila (a wliite spot) in the front. (,', the germ enlarged; u, the head, and /», the body of the embryo, rf, the em- bryo'spider ready to cast off its first skin. The latter circumstance will enable us to explain some experiments made by Redi, wbo kept spiders newly hatched for many months without food.j In the experiments made by us upon the eggs of the wolf spider {Lijcosa saccata), we more than once kept the young in boxes, where they were forgotten and without food; and ^ve uniformly found that they remained lively and well so long as they did not cast their embryo skin; but when they did moult, they could not long survive the want of sustenance.^ In the eggs of moths, the embryo, previous to ex- clusion, may be seen through the shell, snugly coiled * De Geer, Mem. vii, p. 196. t Diet. Classique d'Uist. Nat. xii, 141. t Redi, Esperienze, i)9. § J. R. CONSTRUCTION OF EGG3. 125 up in a ring, as is distinctly shown in many of the beautiful and accurate figures of Sepp.* n, egg of the privet hawk-moth (Sphlrx Li-nistn) magnified, showing the incloseil embryo. I, the caterpillnr, when grown. In the case of tlie eggs of birds, the chick, when fully developed, breaks the shell with its bill, the point of which is then furnished with a hard scale. 'Jhis is evidently contrived by providential wisdom tor this very purpose, for it drops off in a lew days after the chick is excluded. It is probable that the larvae of many insects which are furnished with strong man- dibles gnaw their way through the egg-shell; but we know that there are others which, like the spider, rupture their envelope, since the edges appear ragged and irregular. Others, again, seem to have an open- ing provided tor them, in a door, which c nly requires them to push it open. This is the case with the louse (^Pi