Marine Biological Laboratory Library
Woods Hole, Massachusetts
Gift of F.R. Lillie estate - 197?
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swallowtail butterfly.
( rreen-colored chrysalis.
LIFE CYCLE OF BLACK SWALLOWTAIL BUTTERFLY.
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• •
ELEMENTARY
T
L
STUDIES
IN
INSECT LIFE
BY
SAMUEL J. HUNTER, A. M.
ASSOCIATE PROFESSOR OF COMPARATIVE ZOOLOGY AND ENTOMOLOGY, UNIVERSITY OF KANSAS
CRANE & COMPANY, PUBLISHERS
TOPEKA, KANSAB
1908
Copyrighted by
CRANE A COMPANY, Topeka, Kansas 1902
PREFACE.
NATURAL science studies are essentially studies of things, not books. The teacher in preparing a course of instruction must he governed largely hy the ma- terial procurable. Work in marine biology can never be properly conducted away from the seashore, nor tropical life thoroughly presented in the temperate zone. In the study of animal life, insects present a fertile field. They outnumber all other forms, and are ever accessible. Under observation in their native haunts, or, in many cases, surrounded by artificial con- ditions, they conduct themselves naturally. The study of insects has therefore come to form a prominent part of zoological instruction.
This book on insect life is divided into two parts. Part I deals with the development of insects and their relations to their surroundings. Part II is devoted to Methods, Equipment, and Laboratory Exercises. The laboratory exercises consist of elementary work in the development, structure, function, and systematic ar- rangement of insects. The two parts are intended to be taken together. For example, in the laboratory exer- cises on metamorphosis, the detailed account of the life histories in Part I furnishes additional suggestions on points to be observed; the discussion of the special sense accompanies the anatomical work ; the chapter on wealth of insect life amplifies the schemes of classifica-
(iii)
IV PREFACE
tion ; and so on. The sequence of the work will be de- termined largely by the season of the year. Life his- tories and ecology will naturally be confined to spring and fall. During the winter months anatomical work can be well conducted upon material previously pre- served.
The aim of the book has not been to familiarize the student with a number of isolated facts. It has been the endeavor to induce the student to become ac- quainted, through personal observations in the field and laboratory, with some of the important biological problems as presented by insects. Insects exist in cer- tain given shapes, and in great or few numbers. There are reasons for such conditions, — causes which, wher- ever possible, the student should be led to see. Insects affect one another ; they bear certain relations to physi- cal conditions, and to other forms of life, both plant and animal. They affect man himself. These inter- relations are subjects to be kept in view.
Insect life furnishes many practical subjects for nature-study lessons. Things that live and move elicit the interest and attention of pupils. Nature-study, to have an educative or disciplinary value, must not stop with superficial or passing observations. The educa- tive value derived from nature study does not consist in the number of facts imparted, but in the develop- ment of the ability to acquire knowledge through care- ful and independent personal observation. The pupil at a glance will see that a caterpillar has come out of the egg, the caterpillar has changed to a chrysalis, and later that a butterfly has emerged from this chrysalis.
PREFACE V
In truth, the pupil may have known this before coming under the teacher's guidance. A repetition with no addition will tend to dull the interest. The pupil should be encouraged to see that much remains to be observed. The author believes that there is material in this book which will meet the requirements of nature- study along the lines represented. This opinion is strengthened by the fact that teachers who have pur- sued this work under the author's direction have after- ward used it successfully in the nature-study lessons in the lower grades of the public schools.
The illustrations have received special consideration. In places they supplant the text. For example : Fol- lowing the account of the life cycle of the butterfly, a day-flying form, there are twenty-one figures illustrat- ing the stages of growth and development of a moth, a night-flying form, belonging to the same group. It is believed that this manner of presenting the character- istic differences will tend to induce personal observa- tions on the developing forms themselves.
The colored plates, and drawings where not other- wise credited, are the work of Miss Ella Weeks, to whom the author wishes to express his obligations. These were all drawn from nature or mounted speci- mens, and were originally prepared for this work with the exceptions of figures 153, 154, 156, 158, 159, from articles by the author in the Kansas University Quar- terly; and figures 112, 116, 117, 171, 172, 193-207, 209-211, from contribution ~No. 65, a department pub- lication by the author. Figures 50, 108, 168, 170, and 180 are photographs from department negatives. The
VI PREFACE
remaining photographs, not accredited, have been pho- tographed from nature or preserved specimens by the author for this work.
The author wishes to express his thanks to Miss M. E. Wise for the drawings 'which bear her name, to Professor M. V. Slingerland for photographs, to Pro- fessor E. A. Birge for the nse of electros for figures 5G and 58, to Mr. M. B. AYaite for the nse of electros for figures 72-84, to the Century Company for the electro for figure 65, to the Goulds Company for electros used for producing figures 231-234. Specific acknowledg- ment accompanies each of these illustrations.
Material assistance in the preparation of this work has been given by Professor \Y. C. Stevens, who has kindly loaned a number of photographs, and has read chapter VII both in manuscript and proof; by Pro- fessor V. L. Kellogg, who has made valuable sugges- tions; by Dr. S. AAT. AYilliston, who has read the proof- sheets on the classification of Diptera ; and by Professor C. E. McClnng, who has very kindly read the entire book in proof form. An expression of the author's ap- preciation is but a slight token in recompense for the
value of these courtesies.
SAMUEL J. HUNTER. UNIVERSITY OF KANSAS.
CONTENTS.
PART I.
DEVELOPMENT AND ECOLOGY OF INSECTS.
CHAPTER. PAGE.
I. — THE CYCLE OF LIFE, 1
Incomplete Metamorphosis, 1. — Complete Metamor- phosis. 2. — Molting. -2. — The Life of a Grasshopper, 3.— The Life of a Butteilly. 13.— The Life of a Moth. 24.
II. — THE SPECIAL SENSES, 34
Value of Sense Organs, 34. — The Study of the Special Senses, 35. — The Sense of Touch., 36. — The Sense of Taste, 30.— The Sense of Smell. 37.— The Pro- duction of Odors, 39. — The Sense of Sight, 40. — Sense of Hearing. 43. — Production of Sound, 45.
III. — PROTECTIVE DEVICES, 47
The Hgg's Defense, 47.— The Larva. 50. — The Pupa, 50. — The Adult, 50. — Sympathetic Coloration, 50 — Mimicry, 57.
IV. — SOLITARY LIFE, 02
Social Development, 03. — Mud-daubers, 03. — Digger Wasps, 00.
V. — SOCIAL LIFE, 73
The Colony, 73.— The Queen, 74. — The Drone. 77.— The Worker, 77. — Swarming, 79. — Ants, 81. — Wasps, 85.
VI. — INSTINCT, . . . . 89
Actions of the Newly Born, 90. — Acts of Mature Life, 91. — Acts Associated with Reproduction, 91.— Limitations of Instinct, 92. — Instinct and Reason, 93.
(vii)
Vlll CONTENTS
CHAPTER. PAGE.
VII. — THE MUTUAL RELATIONS OF PLANTS AND INSECTS, . . 94
Plants whose flowers are sterile to their own pollen but fertile to pollen brought from other plants of same species, 96. — Plants whose flowers are so con- structed as to prevent self -fertilization, 104. — The Yucca Lily and the Pronuba Moth, 112.
VIII. — OUR FRIENDS AND FOES, 119
Of the Fruit Grower. — Tent Caterpillar, 123. — Can- ker Worm, 124.— The Codling Moth, 125.— The Honey- Bee, 131.— Wasps, 132.— Parasitic Insects, 132— Pre- daceous Insects, 133.
Of tlie Farmer, 134. — The Chinch-bug, 135. — Grass- hoppers, 137. — The Army Worm, 141.— The Potato Beetle, 142. — Squash-bug, 143. — The Cabbage-worm, 144. — Some Beneficial Insects, 145.
Of the Housekeeper, 147. — The House-fly, 147.— The Buffalo Moth, 148.— The Clothes Moth, 150.— The Cock- roach, 152. — House Ants, 153.
Of Man in General, 154. — The Mosquito, 154. — Bene- ficial Insects, 158.
IX. — THE WEALTH OF INSECT LIFE — ORDERS, 102
APTERA, 165.— The Fish Moth, 166.— The Spring- tail, 160.
NEUROPTERA, 107.— May-flies, 167. — Stone-flies, 168. -The White Ants, 169.— Dragon-flies, 172.— Caddis- flies, 176.
ORTHOPTERA, 176.
Orthoptera that Walk, 178. — Cockroaches, 178. — Praying Mantis, 178. — Walking-sticks, 180.
Orthoptera that Jump, 180. — Crickets, 180. — Katy- dids, 181.— Grasshoppers, 182.
TllYSANOPTERA, 182.
HEMIPTERA, 183.— The Heteroptera, 184.— The Ho- moptera, 185.
COLEOPTERA, 190.
LEPIDOPTERA, 191.— Moths, 193.— Skippers, 193.— Butterflies, 194. DIPTERA, 196.— Fleas, 197.
CONTENTS IX
CHAPTER. PAGE.
HYMENOPTERA, 198. — Plant-eating, 198. — Parasitic, 199.— Stinging, 201.
X. — GEOGRAPHIC DISTRIBUTION AND THE STRUGGLE FOB
LIFE, 202
Habitat, 202. — Barriers, 204. — Barriers to Entrance. 206. — Barriers to Existence, 200. — Fauna, 207. — Zones of Life, 208. — Modes of Distribution. 209. — Deductions, 211.— The Struggle of Life, 212. — Parasitism, 210.— Social Organization, 218. — Feigning Death, 219. — Arti- ficial Selection, 219. — Natural Selection, 220.
PART II.
METHODS AND APPARATUS. STRUCTUiK AND CLASSIFICATION OF
INSECTS. CHAPTER. PAOE.
I. — ACQUISITION AND PRESERVATION OF INSECT FORMS, . 222
Materials for Field Collecting. 223. — How to Make a Net, 223. — Another way to Make a Net, 224. — Preserv- ing Materials, 225. — Field Collecting, 226.— Note- book, 227. — Map of the Vicinity, 228. — Manner of Keeping Records, 228. — Collecting at Lights, 230. — Sugaring, 230. — Preservation of Insects, 230. — Cabi- nets, 234. — Arrangement of Insects, 235. — Relaxing In- sects, 230.— Mailing Insects, 236.
II. — LABORATORY EXERCISES 238
Incomplete Metamorphosis, 238.
The Grasshopper, 238. — Acquisition of Material, 239. — Care of Breeding-cages, 239. — Some Points for Observation, 240.
The Dragon-fly, 240. Complete Metamorphosis, 242.
Swallowtail Butterfly. 242. — Care of Larvae, 242. —Breeding-cage, 243. — Records, 243. — Care of Pupa-, 244.— The Adult, 244.
The House-fly or Bluebottle-fly, 244.— Egg, 244.— Larva, 245.— The Pupa. 24.",.— Adult. 245. Companion Books.
X CONTENTS
CHAPTER. PAGE.
III. — THE HABITS OF ANTS, 247
IV. — FORM AND FUNCTION, 250
Aids in the Laboratory, 251. — Preparation of Speci- men, 253. — Terms vised in Defining Position and Direc- tions, 254.
External Divisions of the Body, 255. — The Head, 255.— The Thorax, 255.— The Abdomen, 255.
The Head, 255.
Fixed Parts of the Head, 255. — Compound Eyes,
255. — Simple Eyes, 256. — Epicranium, 250. — Front,
256.— Genae, 256.— Vertex, 257.— Clypeus, 257. Movable Parts of the Head, 257. — Antennae, 257—
Mouth-parts, 258. — Labrum, 258. — Mandibles, 258.—
Maxillae, 258. — Lacinia, 259. — Galea, 259. — Palpus,
259.— Labium, 259. — Hypopharynx, 260.
The Thorax, 200.— Prothorax, 260. — Prothoracic Leg, 261.— Coxa, 261.— Trochanter, 261.— Femur, 261.— Tibia, 261.
Mesothorax, 261. — Episternum, 261. — Parapteron, 262.— Epimeron, 262. — Ventral View, 262. — Dorsal View, 263.
Mctathorax, 263. — Dorsal View, 263. — Lateral View, 263. — Episternum, 263. — Epimeron, 203.— Ventral View, 263. — The Metasternum, 263. — Metathoracic Leg, 264.
The Wings, 264. — Mesothoracic Wing, 265. — Meta- thoracie Wing, 265.
The Abdomen.— The First Segment, 260.— The Audi- tory Organs, 266. — Second to Eighth Segments, 266.— Caudal Portion of Abdomen of Male. 267. — Caudal Por- tion of the Abdomen of the Female, 268. — Ovipositor, 268.— Egg Guide, 268.— Spiracles, 268.
Internal Divisions of the Body, 269. — Digestive Tract, 269.- — Nervous System, 272. — Respiratory System, 272. —Circulatory System, 275. — Reproductive System, 276.
The Beetle, 276.
Mouthparts of the Cicada, 279,
CONTENTS XI
CHAPTER. PAGE.
V. — KEY TO THE ORDERS AND THE PRINCIPAL FAMILIES OF
INSECTS,
Definition. — Hexapoda, '283.
Orders, 283. — Aptera. 284.— Orthoptera, 285. — Neu- roptera, 280. — Coleoptera, 287. — Hymenoptera, 290.- Hemiptera, 292. — Lepidoptcra, 294.— Diplera, 298.
APPENDIX.
INJURIOUS INSECTS, AND MODES OF DEALING WITH THEM. — REFER- ENCE BOOKS.
Farm J'rurticcs. — Culture, 301. — Preventives, 302. — Rotation of Crops, 302.— Insert icidcs, 303. — For insects that Chew their Food, 303. — For insects with Sucking Mouth-parts, 304. — In- accessible Insects, 305.
Injurious Insects, 308.— Ants, 309.— Aphids, Plant-lice, Green Fly, 309. — Insects Injurious to Apple, 309. — Apricot, 312.- Bean, 312.— Blackberry. 313.— Cabbage, 314.— Cauliflower, 315. Celery, 315.— Cherry, 315.— Corn, 316.— Cucumber, 317.— Cur- rant, 318.— Carpets. 319.— Clover, 319.— Elm, 320.— Goose- berry, 320.— Grape. 320.— House Plants. 322.— Lettuce, 322.- Maple, 323.— Pea, 324.— Peach, 324.— Pear. 325.— Plum, 320.— Potato, 326.— Quince, 327.— Raspberry, 327. — Rose, 327.- Squash. 328. — Strawberry, 328. — Sweet Potato, 329. — Tomato, 329.— Wheat, 330.
Reference Books, 331. — On Protective Devices, 331. — On Social and Solitary Insects. 331. — On Flowers and Insects, 331. — On Our Friends and Foes, 331. — On Wealth of Insect Life, 332.
LIST OF ILLUSTRATIONS.
Life History of the Black Swallowtail Butterfly,
Frontispiece. The Monarch and the Viceroy Plate II.
PAGE.
1. The Yellow Grasshopper (Mclanoplus different ialis) ,
female
2. The Yellow Grasshopper I Mcl<inoi>liift differcntialis) ,
male
Xll CONTENTS
PAGE.
3. Eggs of the Yellow Grasshopper (Melanoplus differ-
entialis) 4
4. Stages of last molt of the Yellow Grasshopper 5
5. Nymph of Melanoplus, first stage 7
G. Nymph of Melanoplus, second stage 7
7. Nymph of Melanoplus, third stage 7
8. Nymph of Melanoplus, fourth stage 7
9. Nymph of Melanoplus, fifth stage 7
10. Melanoplus adult 7
11. Vertical section of ground, showing egg-pods 9
12. Egg-pods of Melanoplus differentialis 10
13. Egg of Black Swallowtail on flower-stem of parsnip. . . 13
14. Newly hatched caterpillar 14
15. Diagram of segments of caterpillar 14
16. Caterpillars of Black Swallowtail feeding on wild celery, 15
17. Caterpillars of Black Swallowtail about to molt 10
18. Caterpillar of Black Swallowtail protruding horns
( osmatcria ) 17
19. Position of Caterpillar of Black Swallowtail before pu-
pation 18
20. Caterpillar of Black Swallowtail about to shed last
larval skin 20
21. The developing chrysalis of the Black Swallowtail 20
22. Brown pupa-case of chrysalis of Black Swallowtail 21
23. Empty pupa-case of Black Swallowtail 22
23a-23w. Twenty-one figures illustrating life of a Moth.. 24-33
24. Heads of male and female Cecropia Moths 39
25. Fragment of outer surface (cornea) of eye of Dragon-
fly 41
26. Head of Dragon-fly 41
27. Section through eye of fly (Musca vomitoria) 42
28. One of the simple eyes of the fly (Musca vomitoria) .... 42
29. Illustrating mode of vision in the many-faceted eye 43
30. Front leg of cricket 44
31. Wing-covers of male Katydid 44
32. Wing-cover of male Cricket 45
33. Lace-winged Fly and eggs 48
34. Insect (Ortliezia graminis) 48
35. Same insect with egg-mass 48
36. Elder cane showing eggs of Tree Cricket 49
CONTENTS Xlll
PAGE.
37. Larva of Caddis-fly in case of sticks 49
38. Larva of Interrogation Butterfly (Grapta interroga-
tionis ) 49
39. Pupa of Interrogation Butterfly 50
40. Dorsal view of the pupa of Black Swallowtail Butterfly, 50
41. Pupa of Interrogation Butterfly on lower side of branch, 51
42. Two pupa-cases of Black Swallowtail Butterfly 52
426. Pupa-case of Black Swallowtail Butterfly 53
43. The Bombardier Beetle (Brachynus americanus) 53
44. The " Stink-bug " (Podisus spinosus) 53
45. " Bags " of the Bag-worm Moth larvae 54
46. The sting of the worker Bee and its appendages 55
47. A Walking-stick 56
48. Leaf Butterfly (KuUinia imrnlccta) 56
4!). Caterpillar and chrysalis of the Monarch Butterfly.... 58
50. Mimicking and mimicked forms 59
51. The Honey-Bee 61
51a. A Fly 61
52. A Wasp 61
52«. A Beetle 61
53. A Bumblebee 61
53«. A Fly 61
54. A Mud-dauber (Pclopoeus cementarius) 64
55. Mud-daubers and their nests 65
56. Ammophila stinging caterpillar 67
57. The Tarantula-hawk (Pepsis fornwsa) 68
58. Ammophila using stone to pound down earth on burrow, 70
59. A queen Bee 74
60. Brood comb 76
61. A drone Bee 77
62. A worker Bee 78
63. Secretion of wax scales 78
64. Head and mouth-parts of worker Bee 79
65. A newly settled swarm 80
66. Hiving a swarm 81
67. " Mud shed " built by Ants for sheltering their " herds "
of Aphids
68. Yellow-jackets ( Polistes sp.) and their nests. . 86
69. Hornets' nest
70. Hornets' nest 88
XIV CONTENTS
PAGE.
71. Female Wasp i ,s'/<Ar.r siicciosnn) carrying a Cicada to
her burrow 92
72. Section of Bartlett Pear flower • 90
73. Buds of Bartlett Pear 97
74. Cluster of Bartlett Pear blossoms 98
75. Flower of Bartlett Pear 99
7G. Bud of the Bartlett Pear, with petals removed 99
77. Bud of the Bartlett Pear 99
78. Bartlett Pear cross-pollinated with the pollen of the
Easter Pear 100
79. Seeds from crossed and from self-pollinated Bartlett
Pears 101
80. Self-pollinated Bartlett Pear 101
81. Baldwin Apple cross-pollinated with pollen of the Bell-
flower Apple 102
82. Large specimen of self-pollinated Baldwin Apple 102
83. Small specimen of self -pollinated Baldwin Apple 103
84. Section of an Apple blossom 103
85. A cluster of Alfalfa blossoms 105
86. Pollination of Alfalfa flower by Bee 100
87. The many-flowered umbels of the Milkweed 107
88. Flower of the Milkweed (Asclepiodora viridis) 108
89. Longitudinal section of Milkweed flower 109
90. Two pollen-masses joined by their bands 109
91. Honey-Bee caught in entrapping slit of Milkweed blos-
som 110
92. Moth held fast in Milkweed blossom 110
93. Insect caught in several flowers of Milkweed 110
94. Honey-Bee caught in several blossoms of Milkweed 110
95. Leg of insect with small chain of corpuscula 112
96. Pollen-masses attached to leg of Bee 112
97. Head of Pronuba Moth 114
98. Ovipositor of Pronuba Moth for insertion of egg in deep
ovary of Yucca Lily 114
99. Female Pronuba Moth ovipositing on ovary of Yucca
Lily 115
100. Female Pronuba Moth thrusting her tentacles and pro-
boscis into the stigmatic opening 110
101. Scale insect (Pulvinaria pruni) on Plum twigs 121
CONTENTS XV
PAGE.
102. Eggs of Apple Tree Tent Caterpillar, surrounding an
apple twig 12.!
103. Parents of the Spring Canker-Worm 124
104. Some Codling Moths 120
105. A Pear and two Apple blossoms 130
100. A Pear and two Apple blossoms 130
107. " Ladybird " and larva 133
108. Ear of Corn, damaged by Grain Moth. . . . 1 •'>.">
109. Tar-covered ridge; barrier to advanec of Chinch-bugs.. 13G
110. A beneficial insect
111. Beneficial Mite 139
112. Plan for hoppenlo/er .... 140
1 13. The Potato Beetle ( l)nri/i>ln,r(i 10-lineata ) 142
114. Squash-bug (Anasa trislifi) ... 143
115. Cabbage Butterfly (Picris rapac) 144
116. Different stages in the transformation of parasitic Fly, 14(i
117. A Fly, parasitic on Grasshoppers 147
US. Bull'alo Moth larva 149
11!). Buffalo Moth I'.eetle (Anthrenus scrophulctriae) . . . . 14!)
120. Larva1 of Clothes Moth feeding on felt 151
121. Egg-pod of Cockroach 153
122. Mosquito (Cnlf.r //?n/</o/.v) in process of development.. 154
123. Full-grown Mosquito larva and pupa 15.~>
124. Mosquito (Ciilr.e jnnii/rns) , female 1~>(>
125. Mosquito (Culex /'«//</''»*) , male 157
120. A Fish Moth (Lci>ixin<i sp. ) Itili
127. Spring-tail ((.'ori/noUirix liurculix) 107
128. A May-fly 108
129. Stone-fly nymph 1G9
130. A Stone-fly ( l'< rla cphi/rc) 109
131. White Ants 170
132. A king White Ant 170
133. White Ant queen 170
134. Nest of White Ants on post 171
135. White Ants' nest on trunk of tree 171
136. Dragon-fly (Libcllulu tnildn-U<i ) 172
137. A Damsel-lly 173
138. Dragon-fly on the lookout for prey . 174
139. Side and top view of head of nymph of Dragon-fly 175
XVI CONTENTS
PAGE.
140. Skin of nymph from which Dragon-fly has emerged 175
141. A Bird-louse (Eurymetopus taurus) 175
142. A Caddis-fly (Leptocerus dilutus) 176
143. The home of the Stone-fly and the Caddis-fly 178
144. Young Mantis on the lookout for prey 178
145. Full-grown Mantis patiently waiting for an opportunity
to seize any small, unwary creature 180
146. A Mole Cricket (Oryllotalpa borealis) 181
147. Broad-winged Katydid 181
148. A Thrips 183
149. Box-elder Bug (Leptocoris trivitattus) 184
150. An Assassin-bug (Melanolestes picipes) 184
151. Giant Water -bug (Belostoma americana) 185
152. Cicada and cast-off nymphal covering 185
153. Newly hatched Scale insect 186
154. Female Scales (Aspidiotus greenii) 186
155. Adult female Scale insect (Kermes nivalis) 187
156. An unprotected Scale 187
157. Adult female Scale (Kermes pubescews) 188
158. Protected Scale insects 188
159. Protected Scale insects 189
160. Adult male Scale insect (Aspidiotus ancylus) 189
161. A Water Scavenger (Hydrophilus triangularis) 189
162. A Click Beetle (Alaus oculatus) 190
163. Wood-boring Beetle at work 190
164. A Snout Beetle (Sphenophorus ochreus) 191
165. A lake overgrown with lilies 192
166. The " Humming-bird " Moth (Phlcgethontius celeus) . . 193
167. Luna Moth (Actias luna) 194
168. " Pitcher " pupa of " Humming-bird " Moth 195
169. A Skipper (Endamus [Thorybes] bathyllus) 195
170. Interrogation Butterfly (Grapta interrogationis) 195
171. A Fly (Sarcophaga cimbicis) and its pupa-case 196
172. A Robber-fly (Erax cinerascens] with pupa-case 197
173. A Flea (Ceratopsyllus serraticeps) 197
174. A wood-boring Hymenopteron, the Pigeon Horn-tail
( Tremex columba ) 198
175. Parasitic Hymenopteron (Thalessa lunator) drilling... 200
176. Map showing habitat of the Swallowtail Skipper (Euda-
mus proteus ) 203
CONTENTS XV11
PAGE.
177. Map showing habitat of the Brown Elfin Butterfly
(Incisalia auyustus) 205
178. Map of United States, showing principal zones of life.. 210
179. Long-winged Grasshopper of the plains (Dissostcira
loii<iii>('iiiiis) 213
180. Grasshoppers invading a city 215
181. Cecropia larva bearing cocoons of a parasitic Bee 218
182. Net and hoop 224
183. Plan for a net 224
184. Map of collect ing vicinity 229
185. An insect mounted on card-point 232
186. Spreading-board for Lepidoptera 233
187. A student's cabinet 235
188. A convenient breeding-cage 243
189. Foot of House-fly 245
190. Board plan for an artificial Ant-nest 247
191. Plan for simple microscope stand 251
192. Cyanide bottle 253
193. Front view of head of Grasshopper 256
194. Clypeus and labrum 257
195. Front view of Grasshopper head with mandibles spread
out 258
196. Inner view of maxilla 258
197. Labium 259
198. Side view of prothorax with leg 260
199. Side view of thorax 262
200. Ventral view of thorax 262
201. Meta thoracic or jumping leg 264
202. Dorsal aspect of body 265
208. Exterior view of auditory organ 266
•204. Side view of male 267
205. Dorsal view of caudal appendages of male 267
206. Side view of abdomen ( female ) 268
207. Side view 269
208. Digestive system of Bee 270
209. Digestive, circulatory and nervous system of female
Grasshopper 271
210. Respiratory system 273
211. Reproductive system of female Grasshopper 276
XV111 CONTENTS
PAGE.
212. Kummaging Ground-beetle (Calosoma scrutator) 277
213. Skeleton of Calosoma scrutator 278
214. Head of Cicada 281
215. Various forms of antennae of Beetles 287
216. Tarsi of Beetle 288
217. Thorax of Wasp 291
218. Thorax of Wasp 291
219. Wing of Coreid 292
220. Wing venation of Lygseidse 292
221. Wing venation of Capsidse 292
222. Wings of a Notodontid 295
223. Wing of a Hepialid Moth 295
224. Wings of a Geometrid 296
225. Wings of a Noctuid 29G
226. Wings of an Arctiid 297
227. Antennae of Diptera 298
228. Thorax of a Crane-fly 298
229. Wing venation of a Syrphid 299
230. Wing of a Muscid 299
231. The " Pomona " spray pump 304
232. " Kerowater " spray pump 306
233. Seneca spray-nozzle 308
234. Vermorel spray-nozzle 308
TOTAL NUMBER OF FIGURES, 25G.
ELEMENTARY STUDIES IN INSECT LIFE
CHAPTER I THE CYCLE OF LIFE
HE passage of nearly every insect from the egg- stage to maturity is marked by a series of changes,— gradual in some, abrupt in others. The insects which change gradually maintain the same general appear- ance and structure throughout life. The insects with abrupt changes pass through stages in which forms are assumed very unlike and not easily associated. These striking and radical changes which take place in growth and development are termed metamorphoses.
Incomplete Metamorphosis.- -The young grasshopper escaping from the egg has much the same form as its parent, and the casual observer easily recognizes it as a grasshopper, the only marked difference being that it is smaller and wingless. In time, however, the full size is attained, and with it proportionate wings. The growth (increase in size) and development (change in form) of this insect go on without any abrupt changes. Insects which mature in this way are said to have an
(1)
ELEMENTARY STUDIES IN INSECT LIFE
incomplete metamorphosis, and in the immature stages are spoken of as nymphs.
Complete Metamorphosis.-- It is sometimes difficult to associate the identity of a bright-winged butterfly with that of some ugly caterpillar. Nevertheless, every but- terfly was once a caterpillar, and not infrequently the most repulsive caterpillar becomes the most attractive butterfly. The honey-bee conies from a white grub, the house-fly from a maggot. Insects which develop in this manner are said to have a complete metamorphosis. They emerge from the egg in a worm-like form called the larva, or the larval stage ; growing to considerable size in this form, they pass into a very dissimilar stage, the chrysalis or pupal stage, in which the insect is quiescent and non-feeding, and during which the fully matured insect is developed.
Molting1. — All insects, during their growth and de- velopment from the egg to maturity, undergo at certain periods a process commonly known as molting. The outward indication of this process consists in the shed- ding of the skin. These changes are not alone for the discarding of unyielding or chitinous coverings to permit enlargement in bodily size, but are as well physiological processes, attended by marked changes in tissues and organs.
Insects with a complete metamorphosis appear in four forms: the egg, the larva, the pupa, and the adult; while in those with incomplete metamorphosis there are but three forms : the egg, the nymph, and the adult. In order that these two methods of insect growth and development may be more fully understood, a type of each has been selected for illustration.
THE CYCLE OF LIFE O
The Life of a Grasshopper.— - Fashions and changes in dress are not limited to people alone. In the cornfields or in the protective shadow of some tall weeds by the roadside, or probably in your own garden, the grass- hoppers are laying aside old garments for bright new ones. This is happening every day during the warm summer months. These changes are made, because, like children, they have outgrown their clothes. In other words, the skeleton of the grasshopper, as we shall see later,, is rigid and surrounds the body, acting as an armor against the rough blades of grass and the attacks of other insects.
FIG. 1. The yellow grasshopper (Melanoplus differentialis), female. From photograph.
FIG. 2. The yellow grasshopper (Jlelanoplus diffcrentialis), male. From photograph.
ELEMENTARY STUDIES IN INSECT LIFE
The grasshopper,* which has been selected to illus- trate incomplete metamorphosis, spends the cold win- ter days as an embryo, in an egg snch as shown in Figure 3, along with a hundred or more similar eggs in a pod laid in the ground the previous fall by the mother insect. These eggs quietly await the warmth of spring to bring them to life.
FIG. 3. Eggs of the yellow grasshopper (Melanoplus diffcrentialis). Enlarged.
The young insect, soon works its way to the surface, where food is sought for strength and growth ; and as it grows it assumes new forms and new garments. This change of clothing, or shedding of skin, more properly called molting, takes place a number of times during its youth. The most interesting molt is the last one, the one in which the grasshopper brings out fully de- veloped wings from the wing-pads in the skin which is being cast off. The observations recounted in this chap- ter were made in a cornfield ; and from sketches taken
* The yellow grasshopper, Melanoplus diffcrentiaUs.
THE CYCLK OK I. IKK
FIG. 4.
DESCRIPTION OF FIG. 4. Various stages of the last molt of the yellow grasshopper (Melanoplus differentiaiis). 7, nymph just before the breaking of the skin along back of thorax ; 2, nymph beginning to come out ; 3, mature insect dropping to the ground ; 4, cast-off skin, still clinging to the leaf; 5, grasshopper climbing up, spreading wings to dry, and getting ready to eat ; 6, fully developed grasshopper on corn-stalk.
6
ELEMENTARY STUDIES IN INSECT LIFE
at that time, Fig1. 4 lias been constructed to illustrate this interesting transformation.
Up to this time in its growth the grasshopper is spo- ken of as being in the nymphal stage. The plate shows the transformation from the nymph to the adult, or as we might say, from youth to maturity. The full-grown nymph ceases to eat, and with the head almost invaria- bly downward, the antenna? drooping, fastens its claws firmly into the stalk or blade and remains quiet for a short period, during which it can be handled without being disturbed ; a pulsating motion begins in the cen- ter of the back of the thorax ; this increases until the whole thorax moves up and down ; soon the skin splits along the back from the top of the head to a line cross- ing the base of the front wings; the upheaving action of the thoracic muscles continues until the body drops to the ground, leaving the nymphal skin clinging to the leaf; the antennas lie on each side of the face, and are thus drawn out. from under the body; the wings come straight out of the pads, narrow and much wrinkled. They are about five-eighths of an inch long when the insect falls to the ground. The insect now is pale, al- most colorless. Inside of an hour, depending upon the weather and time of day, the wings attain their full length, one inch to one and one-quarter inches, and the characteristic colors appear. The legs are not brought into use in discarding this skin. Frequently the claws of the old skeleton break away from their attachment, and the insect falls to the ground. This in no way interferes with the transformation. The insect, when free from the old covering, though its limbs are quite soft and unable to maintain its weight well, crawls to
Till'; CYCLE OF LIFE
some secluded place, where it awaits the hardening- of the body-wall and the expansion of the wings. Before this is fully completed the insect again begins eating.
The morning hours are the best times for you to look for this change, though frequently it occurs in the late afternoon. If in your rambles you observe a nymph which does not jump away when you come near it, and which does not sit, erect but is rather drooping, watch it and you will very likely be rewarded by seeing this interesting change.
FIG. 5. Nymph of IHelanoplus, first stage. After Emerton.
FIG. 6. Nymph of Slelanojrtus, second stage. After Emerton.
FIG. 7. Nymph of Melanoplus, third stage. After Emerton.
FIG. 8. Nymph of Melanoplus, fourth stage. After Emerton.
FIG. 9. Nymph of Melanoplus, fifth stage. After Emerton.
FIG. 10. Melanoplus adult.
This grasshopper of which we are speaking has a variety of tastes and seems to know where to find good
8 ELEMENTARY STUDIES IN INSECT LIFE
things, but if these are not at hand it will satisfy itself with such fare as can be procured. For instance, it wisely climbs up a tree and eats the fruit before disturb- ing the leaves of the tree. If fruit or cereals or garden vegetables are not at hand, it can make a very good meal upon sunflowers. These grasshoppers, like many other insects, are creatures of habit, and their days are spent generally in about the following way: Before sun- rise the nymphs and adults begin to climb to the tops of weeds or fence-posts, and remain there till about ten o'clock. If the article upon which they rest is edible, they amuse themselves by nibbling away. About ten o'clock in the morning they descend, and feed lower down. During the middle of the day they hop about, generally moving in some one direction. The instinct of fear is not wanting even among grasshoppers, and the smaller ones always give place upon the approach of the older ones. About three o'clock in the afternoon these insects take some elevation, much the same as they do in the morning, to remain until sundown and some- times even throughout the night. Grasshoppers are strongly influenced by the weather. On cool and cloudy days they are sluggish and inactive; on warm and sultry days they live an active life.
Thus they spend the time until the fall of the year. Then the females deposit their eggs, which are to con- tinue the species. It is not difficult during September and October to observe the females ovipositing. When they have begun, they are not easily disturbed. A fe- male in quest of a suitable position for placing the eggs generally moves slowly about for some time, testing the ground over which she passes. During this time the tip
T II 10 CYCLE OF LIFE
9
of the abdomen is turned downward, and, stopping' mo- mentarily, the ovipositors (Fig. 1!)S, o) are applied to the ground. Some, however, begin to dig and complete the work where the first attempt is made. Small ele- vated spots on the surface, appear to he much chosen. Frequently these little hillocks arc not noticeable until marked by a locust digging into the crest. From Figure 12, //, //, y", it is evident that for oviposition the same place is sometimes chosen by several grass- hoppers. Sandy soil, when present, seems preferable.
FIG. 11. Vertical section of ground, showing two egg-pods of yellow grasshop- per in position in ground at right; female yellow grasshopper digging holo in which to place her eggs ; longitudinal section of egg-pod at left, showing position of eggs iu pod. Drawn from life.
A suitable place chosen, the locust forces a hole in the ground by means of the two pairs of horny-tippet 1 ovipositors at the end of the abdomen. These are opened and closed and the full weight of the bodv is brought to bear on them. In this way a reeepfaele is made for the eggs/ of ten in extremely firm ground.
Pctf/e W,
FIG. 12.
THE CYCLE OF LIFE 11
Description of Fig. 12.
Egg-pods of Melanophis differentiah's taken from a sandy soil, showing variations in shape, a, pod with top broken off ; b and b' ', pods made of sand with larger grains of sand or stone adher- ing ; c, small portion of outside shell broken off ; d, specimens made of sand and dirt with stones or clods of dirt firmly fixed to the side ; e, specimens broken off near the top ; F, shows an unfinished pod — the grasshopper was disturbed while deposit- ing eggs, and the pod was taken in this unfinished state ; g and g', specimens taken, showing two pods firmly fixed to each other, composed of sand ; g", four pods of sand and dirt, with small stick and dead rootlets adhering ; Fr, cross-section of top of pod, showing honeycomb structure made by the seba- ceous fluid when dry.
12 ELEMENTARY STUDIES IN INSECT LIFE
Each egg is preceded by a light-colored mucous fluid. Part of this fluid passes through the walls of the cavity and causes surrounding particles of dirt, sand, and in some cases small clods (see Figure 12, c/) to adhere; so that the pods when removed from the ground are protected first by a coat of this sticky substance and then by an outer layer composed of particles of surrounding earth. This forms a brittle crust which, when pressed, often scales off, as shown by Fig. 12, c. If the ground is firm, the walls of the pod are generally broken away when the earth is disturbed, thus expos- ing the naked eggs.
This substance before hardening is quite plastic; after hardening it is somewhat fragile. It is insoluble in water, and thus protects the eggs from rain or snow. When the eggs are all deposited the female covers them with a small amount of this sebaceous fluid. This hardens into a honevcomb structure, as shown in cross-
J
section of top of pod, Fr in Fig. 12. The cross-line near top of pod, at // in Fig. 12, shows depth, of covering. The whole pod is finished about one-quarter inch below the surface of the ground, and the ground covered over, leaving no trace of work, as shown on ground surface in Fig. 11. The arrangement of eggs is shown in the longitudinal section of the pod in the foreground of Fig. 11. The number of eggs in a pod is about 100.
Eggs placed in the ground at this late season, the fall of the year, will not receive heat enough to hatch, so that the species passes through the rigorous period of winter in the ea'g sta^e. During the first warm
TIIK CYCLE OF LIFE
13
month of spring the eggs hatch, and the cycle of grass- hopper life begins to repeat itself.
The Butterfly.- -Butterflies arc and have been fertile subjects for the writer's pen and the artist's brush. The velvet-winged butterfly is a symbol of the light, the careless, the free, and the beautiful. Let, us see whether " it toils not, neither does it spin " can be said truly, of the butterfly. For study let us take a general favor- ite, the black swallowtail.1 The female butterfly seeks her nourishment from the apple and thistle blossoms, but when the time has come for egg-laying she sails to some neglected corner in the garden, or shady, unfre- quented dell where the wild parsnip2 or the wild celery3 grows, or some other plant of this family.4
It was during the first days of June we watched her. She placed her pale yellow eggs singly on the small flower-stems of the cluster.
These globular eggs are about one- twenty-fifth of an inch in diameter, and soon become brownish gray, soft and ' moist. Such conditions indicate that swaiiowtaii on
. flower-stem of
hatching is about to occur, (bee trontis- wad parsnip, piece.) At this time, with the aid of a Enlarged' hand-lens, motion may sometimes be perceived inside of the semi-transparent shell. A little black point ap- pears through the shell: it is the tiny mandibles eating their wav, making a round hole sufficiently large for
(/ 7 O «/
the little dark caterpillar, wriggling and twisting, to escape.
1 Papilio polyxenes Fabr. tPeucedanwnffKniculaceum.
-Pastinaca saliva L. * L'mbelliferce,
ELEMENTARY STUDIES IN INSECT LIFE
FIG. 14. Newly hatched cater- pillar of the black swallowtail on flower-stern of wild parsley. Enlarged.
When first this larva measures itself upon the flower- stalk it is three-twenty-fifths of an inch long, — three
times the diameter of the egg from which it came. After stretching itself and resting a moment it turns around and makes its first meal off its shell, — not prompted so much by hunger as by the protective instinct which leads it to en- deavor to remove all traces likely to lead to its discovery by an enemy.
As it stretches itself out again, study it under the hand-lens. It has the normal number of segments, twelve besides the head. Each segment has six p r o t u b erances, and from each of these in turn grow five or six hairs, making in all a rather bristling little crea- ture. The first three segments of the body, known as the thorax, have true jointed legs, each with a horny claw for grasping the supporting twig; the sixth, sev- enth, eighth, ninth and twelfth have each a pair of soft unjointed legs, or pads known as prolegs, aids in locomotion and in maintaining position " when the Avind blows."
Its purposes, intuitions and instincts have been placed in verse.
FIG. 15. Diagram showing normal number of seg- ments in a caterpillar.
TI1K CYCLE OF
15
Born, bred, with just one instinct, — that of growth :
Her quality was, caterpillar-like,
To ail-unerringly select a leaf
And without intermission feed her fill,
Become the Painted Peacock, or belike
The Brimstone-wing, when time of year should suit ;
And 'tis a sign (say entomologists)
Of sickness, when the creature stops its meal
One minute, either to look up at heaven,
Or turn aside for change of aliment.
Broivnuu/ — " Red Cotton Night-Cap Country."
FIG. 16. Caterpillars of black swallowtail feeding on wild celery. Photographed from life.
During the first five or six days of its existence this caterpillar becomes three-fourths of an inch long, black or very dark brown, excepting a white band around the sixth and seventh segments. It now prefers the tender flowers, eating all the parts but the yellow petals, which drop off untouched. (See frontispiece.)
Throughout the caterpillar's growth at certain periods an interesting process occurs. It sheds the cuticular skin, an action frequently called molting. This gen- erally takes place during the early morning hours.
16
ELEMENTARY STUDIES IN INSECT LIFE
For a long time the larva rests quietly, and the skin becomes like an old garment. Undulatory movements of the body headward, slow at first, then increasing, crack the skin around the neck; the caterpillar, pulling itself forward, pushing the skin backward, throbs and pulsates until the skin crumples up unbroken at the end of the body. The head is thrashed about from side to side, occasionally rubbing and striking the stalk, until the hood is discarded. From ten to fifteen min- utes of its lifetime arc required for each change in
FIG. 17. Caterpillars of black swallowtail about to molt. Photographed from life.
clothing. The caterpillar, with its new, whitish, almost colorless coat, rears up its head, remains nearly motion- less for about an hour. This is time sufficient for the characteristic colors to develop and for recuperation. Prompted by the same instinct which caused it to con- ceal its shell-house, its first act now is to turn around and devour the old covering. The fasting, the exertion in eating the skin, every act of the whole performance tends to sharpen the appetite. It eats voraciously, not the tender flowers as before, but the seed-pods and large
THE CYCLE OF LIFE
17
by the finger. Photographed from life>
stems and leaves. This caterpillar no longer requires a milk diet.
Its horns, present from birth, are now even more noticeable and their use is more readily discerned. For, when disturbed by any object other than one of its mates, the caterpillar pro- jects its soft, fleshy, orango- yellow horns from behind the head. The position of the horns, their formidable appear-
FIG. 18. Caterpillar of black
ance, and the act Of protrild- swallowtail protruding horns
(osmateria) upon being touched
ing them, all tend to frighten
away approaching foes. There
still remains, as a last and most effective means
of defense, a repulsive odor arising from these horns,
sensible ten or twelve feet away. This offensive odor
saves many a caterpillar from the destructive beaks of
insectivorous birds.
Sociability is not one of the characteristics of this immature butterfly. If one caterpillar encroaches upon the other's territory, violent displeasure is manifested by the dashing of the head from side to side. Never at such times are the horns protruded, nor is the offensive odor emitted. Why?
At about three weeks of age the larva has grown until it is about as many inches in length, has changed its skin five or six times, has discarded the tubercles and spines so prominent in the young thing just out of the
egg. It is ready to become a chrysalis, a pupa, an in-
—2
18
ELEMENTARY STUDIES IN INSECT LIFE
active form before which we may stand, and, like Tennyson to the flower, say:
"If I could understand What you are, root and all, and all in all, I should know what God and man is."
This interesting caterpillar, thus far content to remain upon the plant where its parent placed it, now grows restless, leaves the seed-pods, descends the flower-stalk, sometimes forsakes t lie plant entirely. In any case it choses some secluded spot on a lower hranch of its food plant, the dead limh of an adjoining tree, or a neigh- boring fence-hoard, as a place for its subsequent transformations. In the vivarium they adapt themselves to the circumstances. One we watched chose the wire screen of a breeding- cage, another the handle of a silver cnp which held the food plant. In nature, however, these caterpillars seem to show a decided preference for slanting objects when selecting a loca- tion for pupation.
The changes undergone by a cater- pillar in passing from the larval to the pupal stage have always excited much interest and elicited the closest attention of the observer. Words to portray the transition. It must
FIG. 19. Position of caterpillar of black swallowtail just before pupation. Slightly en- larged. Photographed from life.
are inadequate
THE CYCLE OF LIFE 19
be seen to be appreciated. The caterpillar begins to spin from its mouth fine white silken fibers, not unlike a spider's thread. The fore feet are brought into use a little in drawing ont the thread to the proper length. A cushion about two-twenty-fifths of an inch in diameter is constructed of this material. Strengthening threads are woven over and about this pad, making it doubly secure in its position. To this cushion the bodv is firmlv fastened by means of the last
t/ €/ </
pair of prolegs. The caterpillar frequently tries its " hold " before fixing itself. Should the silken founda- tion not feel firm enough for the responsibility about to be imposed, the larva releases its grip, turns around and reinforces the cushion with additional fibers.
A firm hold is then taken with the anal prolegs; the caterpillar rests head upward, with the body slightly contracted. After a moment it turns the head and thorax to one side as far as possible, fastens a thread of silk to the supporting object ; then, bending the head backward at almost right angles to the body, it carries the thread slowly by short jerks to the opposite side, fastens it securely, and brings back another thread in the same manner to the starting-place. This is repeated until fourteen or fifteen threads form a loop in front of the head. Into this the head and five segments of the body are thrust, allowing the band to slip into the groove between the fifth and sixth segments. The body now hangs head uppermost in the silken loop, with the caudal extremity clinging to the silken pad. The caudal extremity is the only part of the body in contact with the support. The caterpillar grows shorter, the seg- ments appear swollen, the head curls forward. In this
20
ELEMENTARY STUDIES IN INSECT LIFE
FIG. 21. The de- veloping chrysalis of the black swal- lowtail. Discarded larval skin, mue^i wrinkled, still on FIG. 20. Caterpillar of black swallowtail about lower part of body.
to shed the last larval skin. Enlarged to show Photographed from
"cushion" and "silken loop." Photographed
from life.
state the insect remains suspended for from nineteen to thirty hours.
At the end of this resting period the whole body begins to contract, expand, and twitch; the skin has become thin, old, and almost imperceptibly begins to move backward, gathering in tiny folds ; it breaks on the back along the median line of the thorax. The body movements increase, the central portion elongates, the thorax rests back heavily npon the silken loop. The whole covering, the feet, the head, all appendages are discarded from the posterior end, which is loosened momentarily for the purpose. The caudal end is again
THE CYCLE OF LIFE
21
thrust into the silken cushion,, and there before our eyes the characteristic colors of the chrysalis appear,— at first green, in some cases remaining so throughout pupation, in others turn- ing a protective wood- brown with a dash of frosty-white here and there.
This June generation has all experienced the wonderful transition be- fore the month's end. Each is encased in a hard brown shell, a cov- ering admirably adapted for the changes which occur during this quies- cent period. This shell is protected at every point of probable contact by callous projections. Capable of no external million, the pupa lies in a trance, as it were, for from ten to twenty days, according to the character of the weather, — warm weather favoring growth.
/ r^ o
When it is known, however, that the being enters this tenement as a caterpillar and conies forth by-and-by a bright butterfly, it is evident that great activity has existed within this shell. The hour when we are to see the butterfly is foretold by a duller color, the line markings become less distinct, the shell appears to be-
FIG. '22. Brown pupa-case or chrysalis of black swallowtail. Enlarged. Photo- graphed from life.
22
ELEMENTARY STUDIES IN INSECT LIFE
come moist; then the case gives way along the back, owing to the muscular contractions within, opening a way for the appearance of the black head and legs. Slowly and cautiously the legs become effective, and in a moment's time the smooth inner walls have permitted the escape of the delicate creature ; cautiously it climbs over the old shell to the supporting twig, there to await the sun's strengthening action upon its four wrinkled, folded and limp wings. The body strengthens, the wings expand, the colors stand out, the life and courage increase, and it takes its initial flight. (Frontispiece.)
" Butterfly, good-by to your shell, And bright wings speed you well."
This butterfly, in the form in which we have thus far studied it, had, during its caterpillar stage, a mouth with jawrs fitted for mas- ticating vegetable food. During this eating period sufficient nour- ishment was stored for pupation. Now this same individual, in adult form, a butterfly, no longer has the means nor the power for biting off bits of plant leaves. The butterfly, then, must obtain its food in an- other form. This it finds in the nectar of flowers. To enable it to reach the nectaries within the blos- som, the butterfly is equipped with a long sucking-tube or proboscis. You will not readily perceive this when you first capture the butterfly, since,
FIG. 23. Empty pupa-case of black swallowtail, show- Ing characteristic opening through which butterfly emerged.
TIIK CYCLE OF LIFK 23
while not in use, this tube is tightly mi led up in front of the head. The length of this sucking-tube in the black swallowtail is about three-quarters of an inch. With insect in hand, a careful examination of its parts will no doubt, reveal the position and extension of this butter- fly's mouth. As you might-suppose, then, the swallow- tail is a frequent visitor to the blossoms of flowers. It is fond of the nectar secreted by the thistle and apple, and has been known to visit the verbena blossoms to such an extent that flowers could not be obtained, since the butterflies in withdrawing their tongues pulled the flowers all to pieces.
They are low flyers, and when not disturbed wend their way back and forth about the meadows and pas- tures. If alarmed, however, they greatly increase their speed, darting here and there in a zigzag course. Self- preservation is no less manifest in this delicate form than in those animals of greater size and longer dura- tion of life.
ELEMENTARY STUDIES IN INSECT LIFE
Six egg-shells from which young cecropias have hatched. The young cecropia emerging from the seventh. Photographed from life. ( Enlarged.)
Young cecropia, first stage. Color, black. (Enlarged.) Photographed from life by M. V. Slingerland.
Young cecropia, second stage. (Enlarged.) Color, ebscure yellow. Photographed from life by M. V. Slingerland.
THE LIFE OF A. MOTH (Samia cecropia).
THE CYCLE OF LIFE
25
Young cecropia, third stage. (Enlarged.) Pho- tographed from life by M. V. Slingerland.
Cecropia molting the fourth and last time — natural size. Photo- graphed from life by M. V. Sling- erland.
THE LIFE OF A MOTH (Samia cecropia).— CONTINUED.
26
ELEMENTARY STUDIES IN INSECT LIFE
Cecropias after fourth molt — natural size. Photographed from life by M. V. Sllngerland.
THE LIFE OF A MOTH (Samia cecropia). — CONTINUED.
THE CYCLE OF LIFE
27
Cecropia, full grown — natural size. Color, dull green. Tubercles, blue on sides, yellow on back. The four large tubercles near head are reddish. Photographed from life by M. V. Slingerland.
THE LIFE OF A MOTH (Samia cecropia). — CONTINUED.
28
ELEMENTARY STUDIES IN INSECT LIFE
Cecropia spinning Its cocoon — natural size. Photographed from life by M. V, Sllngerland.
THE LIFE OF A MOTH (Samia cecropia).— CONTINUED.
TIIH CYCLE OF LIFE
Cocoon of cecropia. Photographed from life.
Chrysalis of cecropia taken out of cocoon. Photographed from life.
Empty chrysalis from which ce- cropia moth has emerged. Both natural size.
THE LIFE OF A MOTH (Samia cecropia).— CONTINUED.
Four stages In the emergence of cecropia from the cocoon. Photographed from life. £
9
THE LIFE OF A MOTH (Samia cecrovia).— CONTINUED.
THE CYCLE OF LIFE
31
Cecropia just out of the cocoon. Photographed from life. *3 .
Back and side views of cecropia a few minutes after emergence, showing the limp, moist wings beginning to develop. Photographed from life. %.
THE LIFE OF A MOTH (Samia cecropia).— CONTINUED.
Cecropia inoth about naif hour after emergence, wings almost fully Developed, but still limp. Photographed from life. %.
Group of newly hatched cccropia moths in characteristic positions during the development of the wings, pg.
THE LIFE OF A MOTH (Samia cecropia).— CONTINUED
THE CYCLE OF LIFE
'
Adult cecropia moth (female).
THE LIFE OF A MOTH (Samia cecropia). -CONCLUDED
34 ELEMENTARY STUDIES IN INSECT LIFE
CHAPTER II THE SPECIAL SENSES
Value of Sense Organs. --In animal life there arises with the development of the nervous system, the need of transmission of impressions from certain nerve cen- ters to the muscles. This need is fulfilled by the means of motor nerves. External impressions are to be con- veyed inwardly, to special nerve centers. This function is performed by the sensory nerves. In the simplest forms of life, such as the Amoeba, the body of which is composed of but a single cell, special sensory organs are wanting. The outer part or surface is a general sensory organ. While the sensory phenomena of these primitive forms are not well known, it has been ascer- tained that they are sensitive to external stimuli, such as electricity, contact with other bodies, heat, and the actions of certain chemicals. Many are sensitive to light. As the scale of life advances, and animals be- come more complex, the sensory areas become more localized, and their functions more varied. When sensory nerves become grouped in one locality or organ of the body, for a special purpose, we call that location or organ, with its nerves, a sense organ. With this localization there comes also an increase in the power
THE SPECIAL SENSES 35
of the sensibilities. In insect life we find the sense of touch, the sense of sight, the sense of taste, the sense of smell, and the sense of hearing.
The Study of the Special Senses. — Our impressions of the character of the world around ns are based upon experiences gained through organs of special sense. We are acquainted with only those things which influence our senses, and so, in speaking of special senses, we are wont to consider them from our own standpoint. There- fore our study of the senses of those forms of life which cannot communicate their impressions directly to us, must be carried on by comparison with our own impres- sions. In ourselves, we are aware of five senses, namely : smell, touch, taste, hearing, and sight. In our classifi- es lion of the senses of lower animals, we classify the senses of these animals accordingly as the actions of these senses compare with the physiological functions of our own. It is possible that other forms of life have- other senses, but it is somewhat difficult for us to com- prehend clearly the character of a sense which we our- selves lack. Dissections of special sense organs do not always give conclusive evidence as to the significance of the sense organs. For instance, it would be hard to tell, by cutting to pieces, whether a certain organ was used for tasting or smelling, or for either. Our conclu- sions are frequently based upon observations made upon the actions of certain special sense organs. Our present knowledge, then, of special sense organs 1ms been gained by experiments with living Wins, and by anatomical investigations.
36 ELEMENTARY STUDIES IN INSECT LIFE
The Sense of Touch.— - If the soft surface of the tips of the palpi (labial and maxillary) of the grasshopper's mouth (Fig. 195, e, g] he examined under the compound microscope., little peg-like structures will he observed. These are connected with nerves which transmit sen- sations of contact, or touch. These organs derive their names from this function. While this sense is localized chiefly in the palpi, it is not confined to them alone. The antenna1 also serve as tactile organs, but in a varia- ble degree according to their forms, their development, and the habits of the species. Species of beetles with- out eyes find their way about by means of these an- tennae. Our familiar long-horned beetles grope their way among the branches of trees, using their long an- tenna' for the purpose. Insects with long, filiform, many-jointed antenna1 use them as feelers. Insects with short, stiff antenna1, with few joints, evidently do not use them as feelers, and so do not have the tactile sense of the antenna1 developed in such a high degree. In many insects the extremities of the limbs also have nerve cells which convey impressions of touch. The membrane underlying the chitinous covering of insects is sensitive to touch, so that nearly every por- tion of the insect's body perceives contact with foreign bodies.
The Sense of Taste. — The sense of taste has to do with the determination of the character of matter presented as food, and so the organs of taste naturally lie in the vicinity of the mouth. Of the nerves of taste, some are to be found on the palpi of the mouth, situated with the tactile nerve cells, and others on the membranes of the mouth. This sense is verv eloselv connected with the
THE SPECIAL SENSES
37
sense of smell. These organs of taste are minute pits, hairs, or short peg-like structures which form the end of the gustatory nerves, and are most numerous on the membranes within the mouth. They are situated at a point where the food must necessarily touch them as it enters the mouth and passes down the throat.
The sense of taste is highly developed in bees. Ob- servations upon the readiness with which bees use this sense can be made by placing on a large platter, accessi- ble to bees, plain honey and honey mixed with sub- stances likely to be unpleasant to bees. Ants have been drawn to honey in which there was morphine and strychnine. The smell of the honey attracted them, but the moment the honey touched their lips they ceased eating it. Xeither in the antenna' nor anywhere out- side of the month was there any organ which informed them of the unpleasant substances within the honey. An interesting experiment performed with wasps, was as follows: sugar was fed to them from day to day at a certain place, until they became accustomed to coming to that place for the sugar; powdered alum was substituted for the sugar. They had scarcely touched it when they drew back with most comical gestures, (•leaning their tongues by frequently running them in and out and stroking them with their fore feet.
The Sense of Smell.- -The antenna- perform dual func- tions. It has been shown in discussing the sense of touch, that the antenna1 are tactile organs. The an- tenna;- may be regarded also as the principal organs of smell. The nerve endings are similar to those of the nerves of touch, being pits or papilla?. The sense of smell is highly developed among insects. It is con-
38
ELEMENTARY STUDIES IN INSECT LIFE
stantly used. By the sense of smell, insects are enabled to discover food, to recognize their friends, avoid their enemies, and to seek their mates.
These various uses have been confirmed repeatedly by experiments. ( 'ertain carrion-eating beetles inclosed in a large box invariably sought out a small bit of decay- ing flesh within a bottle located in one corner. When the antenna1 were covered with wax, so that the olfactory nerves were no longer sensible, the beetles no longer found the meat. Flies were attracted into a room by a piece of decaying meat. It seemed impossible to drive them away from the meat. These same flies paid no attention to the meat after they had been caught and their antennse rendered insensible. The actions of the insects in other respects seemed normal, so that their indifference toward the meats could not be charged to any discomfiture from the temporarily insensible an- tenmr. Closely constructed boxes in which were in- closed certain species of female moths have attracted the males of this same species. The males of such
FIG. 24. Heads of (a) male and (b) female Cecropia moths. Photographed on same scale, illustrating the greater development of antennce in male moth. X 2.
THE SPECIAL SEXSKS
39
species have boon known to appear at the windows of rooms in which the females wore in captivity. Xow in these moths the antenna1 of the males are hiirhlv (level-
o t>
oped. It seems undoubtedly to be the case that since the males could not see the females, they discerned them through the sense of smell. And this is further evi- denced by the antenna1, the seat of smell, being' more fully developed in the males than in the females.
In the growth and development of insects, we have found that at different stages the strnctnrc of the insect and the food habits are different. The butterfly has a long very lender tube through which it secures its liquid nourishment. It has no jaws with which to mas- ticate the leaves of plain-. The caterpillar which hatches from the egg of this very butterfly has jaws with which to eat. It has also specially formed tastes for certain plant tissues. If the eggs arc deposited in places remote from the proper food plants the young caterpillars will starve, since they have no "taste" for oilier plants and will not cat them. The parent, then, must be able to recognize the proper food plants upon which or near which to deposit her eggs. Her sight, as we shall see presently, is imperfect, and does not clearly recognize the various forms in plants. She cannot taste the plant leaves, and in many eases there are no nectar-bearing blossoms to aid her. Plants give off characteristic odors, and it is upon these she evidently depends for the recognition of the plants furnishing proper nourishment for her young.
The Production of Odors. — Many caterpillars emit offen- sive odors. (See pp. 16, 17.) Certain insects, such as the well known "stink-bugs" (Fig. 45), give off, when
4-0 ELEMENTARY STUDIES IN INSECT LIFE
disturbed, disagreeable scents. These are given off for the purpose of protecting themselves by repelling inimi- cal insects, and more especially other enemies, such as birds. There are, however, odors given off by insects, evidently intended solely for the benefit of other in- sects ; that is, to render themselves by the possession of this odor attractive to other insects. Many of these odors are perceptible to us. Our monarch butterfly1 (Fig. -iSa), emits a slightly honeyed odor; the small blue butterfly,2 common in spring, has an odor resem- bling crushed violet stems. Tin- white butterfly3 gives off a faint odor of syringa blossoms. These instances with many others show that many butterflies emit odors, apparently in most cases agreeable to us. These odors are emitted through minute canals found in very small scales of the butterfly wing. These scales are called scent scales. As far as our sense can perceive, some insects with well-developed scent scales emit no odors. It is evident, then, that the odors which they emit are beyond our perception, and that to such insects we must attribute an exceedingly delicate sense of smell. This statement is not difficult to accept, when, as be- fore noted, the males of many species are able to locate, within a dwelling, entirely out of sight, females of their own species. They do not so much "'walk by sight" as "fly by smell."
The Sense of Sight- -The eyes of insects are of two kinds, simple and compound. Of the simple eyes there are generally three, situated in a triangle on the front of the head. These eyes have but a single lens, and, it is supposed, they are used to observe very near objects. The
lAnosia plcxippus. '- Cyaniris pseudargiolus. sPieris oleracea.
THE SPECIAL SKXSES
41
compound eyes, situated on the sides of the head, are composed of numerous simple eyes, which are complex in structure. The number of simple eves in the com- pound eye varies in different, insects. The ant has about fifty simple eyes in its compound eye. The compound eye of the dragon-fly (Fig. 26) contains
FIG. 25. Fragment of outer surface (cornea) of eye of dragon-fly, much enlarged, showing the hexagonal fac- ets. Drawn from nature by Miss M. E. Wise.
FIG. 26. Head of dragon-fly. En- larged, to show well-developed com- pound eyes forming sides and upper part of head. From a photograph.
20,000 simple eyes. In the compound eye, the outer surface or cornea of each simple eye is hexagonal. These hexagonal surfaces are joined together, form- ing a many-faceted cornea for the compound eye (Fig. 27). These eyes composing the compound eye see in- dependently of eaeli other. Each one is aide to see but a small part of any object before the compound eye, so that insects see images and objects not as entire things, but in mosaic; that is, the object viewed seems to the insect to be composed of many small independent parts.
Some insects do not have eyes. Those insects which live constantly in the dark, such as those which are
ELEMENTARY STTDIKS IX INSECT LIFE
exclusively under the bark of tree-, as a certain beetle;1 or parasitic in tbe skin of certain animals, as the spider- like fly;2 or live in dark caves, as the small ground beetle;3 or lead subterranean lives, as the small beetle4 which dwells in ants' nests.
FIG. 27. Section through eye of fly vomitoria), showing arrangement of nerve-end- ings of simple eyes beneath cornea (c). (After Hickson.)
At certain stages in growth and development some insects find no use for eyes. The larva1 of flies, commonly called maggots, being placed by their parents upon proper food, into which they fre- quently burrow, need no eyes. The same is true of Hymenop- trrons larva\ the offspring of bees and wasps. The larva1 of bec-
Fiu. 28. One of the simple eyes
ties with like habits are also (ommatidiwiO from the compound
eye of the fly (Musca vomitoria).
eyeleSS. Bllt all these forms c, cornea ; pc, pseudocone ; pg'< pig-
, , ,, , . ments surrounding and separating
When they paSS from tlllS Stage each eye from theother ; R, central
,-] -\ -\, r axis of the nerve-ending semidia-
to the adult form possess eyes. grammatic. (A£ter
lPtilium. -Nycteribia. 3Anophthalmus
THE SPECIAL SEXSES
Many larval forms, such as caterpillars and others which move about in quest of food, possess simple eyes in varied numbers.
Just how well and how accurately insects can see, is still an open question. It is evident that insects can perceive objects in motion better than at rest. Anyone who has ever disturbed a bumblebee's home, or a hornet's nest, knows that, though in a comparatively safe place, ;i movement on his part is likely to lead to his dis- covery and bring down the wrath of some scout- ing bee. It is probable, then, that the principal use of the compound
FIG. 29. Illustrating mode of vision in a eye IS tO perceive, not many-faceted eye. (After Lubbock.) The
the form, but the move- "f* hente™ "lrough cornea- ,The rays
which strike the sides of each tube or cone
ment of oblOCtS. It IS are absorbed by the black pigment which
, 11'' • surrounds each tube. Accordingly, those
further believed that 111- rayg Of nght only which pass through the
sects cannot clcarlv per- ^8tal»ne cones diref * ^ ™ ™?«**?
from their sides), such as a-a , b-b , c-c , CeiVC oblCCtS at a (lis- d-d', e-e', will ever affect the nerves at «',
6', c', d', e . According to Lubbock, the
tance greater than SIX larger and more convex the eye, the -wider /• 1 ,i •,! will be the field of vision ; while the smaller
feet away, and that with andmorenumerous are the facets, the more
few exceptions, SUch as distinct will be the vision.
the dragon-fly and honey-bee, insects are guided rather bv the sense of smell than that of siirht.
«> o
The Sense of Hearing.- -The location of the auditory organ in the grasshopper (Fig. 20:5, E, and.} is on the side of the insect immediately back of the thorax.
«/
The oystershell-shaped covering is simply a highly at- tenuated and fully stretched portion of the body cover-
ELEMENTARY STUDIES IN INSECT LIFE
FIG. 30. Front leg of cricket, showing ear-like organ (a).
ing. This cover corresponds in its use to the tympanum of our own car. On the internal surface of this tympanum there are two horn-like processes, and at- tached to these is a very delicate little sac filled with a transparent fluid. This sac represents the membranous laby- rinth, and is connected with the auditory nerve, which goes to the brain. This tympanal structure
is to be found in the common black .cricket, fa- miliar katydid, and their allies, on the inside of the tibia of the front leg. The organs of hearing have different locations in dif- ferent insects. It has been demonstrated that the an- tenna1 of the male mosquito vibrate to the sound-wave of the tuning-fork. It is quite probable that a num- ber of other insects per- ceive sounds through nerves which terminate exteriorly in the antenna1. The functions of the an- tennal nerves of insects are varied, capable of per- ceiving contact, odor, and
FIG. 31. Wing-covers of male katydid, The one on left shows heavy file-like structure on under side near base (en- larged just above wing); the one on right shows membranous structure near base with pointed ridge on upper side (en- larged just above wing), extending out- ward. The right wing is passed under the left wing, the sharp ridge rasps upon the file of the left wing, the membrane of the left wing vibrates, producing the " song " of the katydid.
THE SPECIAL SK.\SF:S
sound. The antennas may be considered, then, to have within them three classes of nerves: nerves of touch, of smell, and of hearing.
Production of Sound. — Insects have no true voice. We are all familiar with the shrill cry of the cicada or harvest-fly, the song of the katydid, and the chirp of the cricket. These are no doubt calls to other individ- uals of the same species. The cicada produces its pierc- ing notes from a pair of membranes on the under side of flic base of the abdomen of the male. The membranes cover depressions and vibrate rapidly somewhat like two kettle-drums. It is only the male that possesses the-e organs. This has led some one to say in rhyme:
" Happy the cicadas' lives, For all have voiceless wives."
The student, with the male cicada in hand, will not have to wait long before he is permitted to hear and observe these sound- producing membranes in action. The katydid brings forth its'song hy rubbing its fore wings upon each other. (Fig. 31.) The male cricket will not usually re- main long under a glass tumbler before he begins rubbing the base of his upper wings on the base of his under wings ( Fig. 32), pro- ducing that familiar clicking sound. Certain moths and but-
Fir,. 32. Wing-cover of male cricket, showing sound-pro- ducing apparatus. Each wing- cover is equipped with our oi these flies, r, enlarged at a, and a scraper. When the cricket wishes to call, he.ele- \ates his wings so that the scraper of each wing rasps mi the tile of the other, when the wings are moved sidewise. This sets the membranous wing-covers in vibration and produces the characteristic chirp of the cricket.
46
ELEMENTAEY STUDIES IN INSECT LIFE
terflies make crackling noises by rubbing their palpi against the base of their long probosces. The buzz of the honey-bee is caused by the vibration of the wings. In Japan a number of insects, notably among them a night cricket, are prized for the peculiar noises which they make. They are looked upon there as we regard canaries, and are kept in cages and cared for simply for the pleasure derived from hearing their character- istic sounds.
PROTECTIVE DEVICES 47
CHAPTER III
PROTECTIVE DEVICES
". ! . . . Then marked he, too, How lizard fed on ant, and snake on him, And kite 011 both ; and how the fish-hawk robbed The fish-tiger of that which it had seized ; The shrike chasing the bulbul, which did hunt The jeweled butterflies ; till everywhere Each slew a slayer and in turn was slain, Life living upon death. So the fair show Veiled on vast, savage, grim conspiracy Of mutual murder, from the worm to man, Who himself kills his fellow."- .!
IN this life, among1 us ;m<l about us, animals and plants as well as men bring to their aid every means which will in anv wav secure advantages to
i/ «/ O
themselves and their posteritv. Man lias inanv cuiminc;
1 *j tj iT
devices; ferocious wild animals have strength and prowess; yet both of these show due respect for the defensive weapons of the hee and the wasp. Bees have stings, beetles have guns. More successful in escaping the many predatory enemies of insects, however, are those that hy imitation or simulation succeed in appear ing not what they are but what they seem.
Means of protection are evident in every stage of insect life: the egg, the larva, the pupa and the adult frequently possess marked tendencies for shielding themselves from harm by reason of some peculiar trait or characteristic.
The Egg's Defense.-- in the case of the egg, too fre- quently members of its own generation are its wors\
48
ELEMENTARY STUDIKS IX TNSKCT 1. 1 II.
enemies. The lacewinged fly [ finds her offspring fond of their uhhatched brethren; so the mother insect pro-
FIG. 33. Lace-winged fly and eggs, showing means of protection used by mother in placing eggs on stiff stalks of hard silk about one-half inch high.
vides a defense for her young still in the helpless stage hy placing each egg upon a pedicel (Fig 33). Now as each egg hatches, the young one drops down upon the
FIG. 34. Ventral view of insect (Orthc- ziu graminis) without egg-mass attached.
Fi<;. 35. Dorsal view same insect with long fluted covering over egg-mass attached to body. A protection for the eggs.
leaf or supporting surface beneath, and his brothers still remain high out of reach of this young bit of active life with an appetite to satisfy.
lChrysopa sp.
PEOTECTIVK DEVICES
FIG. 37. Larva of caddis-fly in case of sticks con- structed by itself as protection against its enemies. When disturbed, it draws itself up within the house of sticks, mud and pebbles.
FIG. 36. Elder cane, showing top view of holes drilled by tree- cricket, a protective receptacle for her eggs. At left, part of cane split to show eggs In posi- tion.
FIG. 38. Larva of Interrogation butterfly (Grapta interrogationis) about to pu- pate, showing protective many-barbed spines. From a photograph. Enlarged.
—4
50
ELEMENTARY STUDIES IN INSECT LIFE
The Larvae resort to many means to escape enemies. Some emit, noxious juices, some " play 'possum/' some assume an attitude of fierceness, and others simulate objects not subject to attack.
The Pupa frequently secures protection by assuming on the pupa-case colors closely resembling1 the support, or by taking the form of some object associated with it.
FIG. 39. Pupa of interrogation butterfly, showing protective knots or processes at exposed points lia- ble to contact with other bodies. From a photograph. Enlarged.
FIG. 40. Dorsal view of the pupa of black swallowtail but- terfly on white saucer, showing protective resemblance. Photo- graphed from life.
The nascent pupa-skin in some insects appears to have the capacity to assume within certain limits the colors of its support. (See Figs. 40, 42, 426.)
The Adult. — Did you ever observe a moderate-sized black or bluish beetle running away from under a stone or board you may have overturned ? Have you
PROTECTIVE DEVICES 51
FIG. 41. Pupa of interrogation butterfly on upper part of under side of branch, protected by its resemblance to a fragment of leaf below it. After photograph by V. L. Kellogg.
ever collected such, and while handling it heard now and then a peculiar popping sound ? These are the bom- bardier beetles. (See Fig. 43.) You will soon learn to know them by their bluish, blackish, or greenish bodies, with head, prothorax and legs yellowish or reddish yel- low. These beetles have at the hind end of the body little sacs in which they secrete a volatile fluid ; so, when one of these bombardier beetles is about to be overtaken by a pursuing enemy, a sudden pop, and he surprises his would-be captor with a report not unlike that of a little popgun, and then bewilders him with a load of smoky gas fired into his face. During this momentary be- wilderment of his adversary, the bombardier beetle makes good his escape.
ELEMENTARY STUDIES IN INSECT LIFE
FIG. 42. Two pupa-cases of black swallowtail butterfly. The one on left has attached itself to white stick, the one on right to black stick, showing adaptation of color of pupa-case to its surroundings. About three-fourths natural size. Photo- graphed from life.
There are but few of us who have not at some time experienced the sting of a bee or a wasp. Among bees this weapon is brought into use, not alone as protection against intruders, such as man, but is much used against the unwelcome visitors of its own tribe. Had not nature equipped the bee with such means of defense, this val- uable insect, on account of the attraction the honey presents to man and other animals, would years ago have succumbed to the attacks of those seeking its precious stores.
PROTECTIVE DEVICES
53
The formic acid and the other toxic elements pmbably present in the fluid ejected from the glands of the body of the attacking bee, while discomfiting to us, are quite deadly to the bees. This poisonous fluid can be secret r. I from the blood-cells of the bees, but when it is injected
FIG. 426. Pupa-case of black swallowtail butterfly on white saucer, side view, showing protective resemblance in coloration of the pupa-case to the white saucer. Natural size. Photographed from life.
FIG. 43. The bombardier beetle (Brachynus americanus). Enlarged three times.
In, .44. The "stink-bug" (Podisus spinosus). Ren- dered distasteful to birds by its ability to give off an offensive odor. Enlarged about two and one-lui'f times.
04 ELEMENTARY STUDIES IN INSECT LIFE
into the tissues, by means of another's sting, death follows. When the honey-bee stings the human flesh the sting generally remains, and the bee, if not killed before, dies on account of the wound caused by the tearing away of the organs connected with the sting. This sting, then, is not so much for the protection of the individual as for the defense of the home and its
FIG. 45. "Bags" of the bag-worm moth larva, made of closely woven web covered by bits of sticks. The larva weaves the "bag" as it travels, for protec- tion. The male emerges as a moth. The female spends her life as a grub-like form in her "bag."
sacred treasures ; true patriots, these bees. Not so with the wasps and hornets : they sting repeatedly without endangering their own lives.
" The sting is composed of two spears of a polished, chestnut-colored horny substance, which, supported by the sheath, make a very sharp weapon. In the act of stinging, the spears emerge from the sheath, about two- thirds of their length. Between them and on each side of them is a small groove, through which the liquid, coming from the poison-sack, is ejected into the wound.
" Each spear of the sting has about nine barbs, which
PROTECTIVE DEVICES
55
are turned back like those of a fishhook, and prevent the sting from being easily withdrawn. When the in- sect is prepared -to sting, one of these spears, having a little longer point than the other, first darts into the flesh, and being fixed by its foremost barb, the other strikes in also, and they alternately penetrate deeper
Fio. 46. The sting of the worker bee, and its appendages. (Enlarged, from Glrard.) a, sting ; 6, poison sac; c c, poison glands ; d d, secreting bags.
and deeper, till they acquire a firm hold of the flesh with their barbed hooks. Meanwhile, the poison is forced to the end of the spears, by miu-h the same process which carries the venom from the tooth of a viper when it bites." (GIKAKD.)
56
ELEMEXTARY STUDIES IX IXSECT 'LIFE
The muscles, though invisible to the eye, are yet strong enough to force the sting, to the depth of one- twelfth of an inch, through the thick skin of a man's hand.
>
FIG. 47. A walking-stick, protected by its re- semblance to its surroundings.
FIG. 48. Leaf butterfly (Kal- lima paralecta) on left, showing protective resemblance to leaf on right. (After Wallace.)
Sympathetic Coloration. — So far we have spoken only of active means brought into use hy insects in pro- tecting themselves. Did yon ever notice that the grass- hoppers which live along the roadway and those living
PROTECTIVE DEVICES
57
almost exclusively upon the sandy and dusty ground, are dust-colored, while other grasshoppers, that live in the grass exclusively, are of a greenish color? Not only are they greenish in color, hut in the case of a certain green grasshopper which spends much of its time upon the lamb's-quarter, there are marks of red corresponding to the red markings upon the green lamb's-quarter, showing further resemblance to sur- roundings. These colors have not been assumed as a
O
matter of choice by the insects, just as we choose the colors of the clothing we wear, but have arisen through slow and gradual development. Is it not evident that the green grasshoppers upon the dusty road would be very conspicuous objects for birds and other enemies ? If perchance a few should he somewhat gray or dusty in color they would be more likely to escape the notice of enemies, and naturally would tend to reproduce others of like color. Thus the matter of color not only becomes firmly fixed but most decidedly pronounced. And the same might be said about the dust-colored insects among the green grass.
"The world is made up,'" says Scudder, "of eaters and eaten, of devices to catch and devices to avoid being caught." So, whenever we find very large numbers of one species of insect life prevalent we will do well to look about to see if we can ascertain what trait of char- acter or propitious conditions have furnished this group sufficient protection to enable the individuals to increase in such numbers.
Mimicry. — A feature of greatest interest among adult insects, and, we may say, one of the most successful in its purpose, is that means of defense which is secured
58
ELEMENTARY STUDIES IN INSECT LIFE
through what we are wont to call mimicry. The defini- tion of this term, a word not in all respects expressing the intended meaning, can probably be best given in illustrations.
We are all familiar with that old-fashioned brown butterfly to be seen lazily making its way over the meadows in the late summer days ; and sometimes in the
Fio. 49. Caterpillar about to pupate, and chrys- alis of the monarch butterfly. Photographed from life.
autumn great strings of them may be seen moving south- ward, or clusters of them hanging to the branches of a tree in such numbers as1 to obscure the color of the leaves. This is the monarch <>r milkweed butterfly,1 to be found wherever the milkweed grows.
From its careful, easy manner of flight in exposed places, this milkweed butterfly evidently takes little thought of predatory birds, and the reason is that in- sectivorous birds care nothing for it. If perchance a bird, a young inexperienced fledgling, pounces upon one of these milkweed butterflies, it soon lets go, be-
lAnosia plexippus.
PROTECTIVE DEVICES
59
ifr^*
FIG. 50. Mimicking and mimicked forms. Forms with W are wasps, with protective stings. All the others are moths resembling wasps. Photographed by V. L. Kellogg.
cause when the beak presses the insect's body, therefrom is emitted a rank carroty odor extremely distasteful to the bird. Possibly every young bird has this lesson to learn at least once --that is, that this brown, black- marked butterfly is not a dainty tidbit. And may we not say that this lesson after repeated learnings by successive generations becomes instinctive, and the in- sect immune from the attack of the birds ?
All this is of great importance in determining the
60 ELK.MKXTARY WTUDIKS IN INSECT LIFE
welfare and existence of this species of butterfly. Other butterflies have not the power to emit this noxious odor and distasteful fluid as a means of protection; but some of them have succeeded by slow and gradual changes in assuming colors closely resembling those of the more favored species.
Most remarkable among these is the simulation of the viceroy butterfly.1 On account of its relation to the milkweed butterfly it has been fitly termed the viceroy, and the milkweed butterfly has been called the monarch. As will be seen from the illustrations (Figs. 48 a, 6), the general appearance of the two is much the same. The viceroy, however, is smaller, and bears a transverse black band upou the hind wing. This butterfly was once much darker than it is now. The brown color was present in a small degree, and this coloring has increased by natural selection until we have the present protective form. ]Ias this change of color been carried on through the conscious activity of the insect '( In other words, "Can the Ethiopian change his skin, or the leopard his spots ( " Mimicry is not consciously carried on, but has to be accounted for by natural selection; that is, those viceroys having the greater amount of brown were more likelv to decei\v the birds than those
«.
with less, — -consequently they lived to reproduce in kind other- with prominent brown markings, and among them those displaying the brown most prominently were most likely to live to reproduce again in turn, the brown colors increasing, and so through a long series
lBasil(irchia archippus.
JJiJ'1 (I'l'ini!
.ylh-
ion/. s*>tfi •;-)l^
^Hr^ >iil i 'i< -
•
Inc. 4Sf/. The monarch butterfly. (A'ltnxia ple.ripi.niit. )
•
• •
Fi<;. 4H/,. The vicbroy l.nttorfly.
( Basiiarchia arcHi.ppiis.)
I
!
'
Fi(4. 48r. Another member of the viceroy genus, />V/x- ilarfhia. To show usual coloring of the othrr of this
s ^'iius.
'
l'l;<)TK< TIVK DEVICES
Cl
of generations until \vc have the present form. Thus natural selection slowly, yet potently, shapes the destiny not only of inserts, but of all animals and plants.
MIMICKED FORMS. Insects with powers of defense. From photographs.
<*>.':
FlG.51.
The honey-bee. (Apis mellijii-ii.)
FIG. 52.
A wasp.
(Vespa occidrntdlix.)
FIG. 53.
A bumblebee. (Bomb its Howardi.)
MIMICKING FORMS. Insects without powers of defense ; protected by their re- semblance to dreaded insects. From photographs.
FIG. 51a.
A fly. (Eristalis latifrons )
T
FIG. 52a.
A beetle.
(Glytus marginicollis.)
•
,. '
FIG. 53a.
A fly. (Volucelld iTi-i-tn i
62 ELEMENTARY STUDIES IN INSECT LIFE
CHAPTER IV
SOLITARY LIFE
SOME insects lead a social life ; other insects are soli- tary in their habits. We find within the insect tribe many hermits, with almost miraculous foresight, expend- ing their lives and energies constructing abodes for the protection. of their young as well as storehouses for food to nourish their young. Unattended, the young grow from infancy to maturity within these little darkened homes, prepared and provisioned by a parent who in most cases has gone before the offspring mature.
The solitary wasps are the most interesting forms of this class. These insects are of two sexes. It is the duty of the female to make a nest for each one of her young, and to see that nourishment is furnished it suffi- cient for its sustenance until maturity. The males are irresponsible creatures, assuming little if any direction in family affairs. The adult wasp lives upon fruit or nectar ; the young are reared upon animal food. Each species is particular as to the kind of food selected, so that we find certain species always provisioning their nests with flies, others with spiders, others with cater- pillars, and yet others with grasshoppers, and so on. Generation after generation and year after year the same species are reared upon the very same class of food, pro- cured in like manner by the parent guided by the force we are wont to call instinct.
SOLITARY LIFE 63
Social Development— In the development of social life among insects we find all gradations, — the solitary, the gregarious, and the social. The independent insects, such as the chinch-bug;, take little thought for their off- spring. Then come forms such as the solitary wasps, to he treated further on; these provide for their young. Then come the mining-bees, which live apparently in communities in sandbanks, but which in reality have but an entrance or hall in common, off from which each in- sect has a separate apartment where no other intrudes. Then come the ants and bees with their communistic life, division of labor and sharing of responsibilities. In such an organization is to be found the most advan- tageous plan of life. The ant alone is helpless, but in its organization, the colony, it is one of the most suc- cessful, because, by reason of numbers and division of labor, it secures protection, food, shelter, and insures like conditions for its offspring. The most successful are the most sociable.
Mud-daubers.— -Familiar to all of us are the mud- daubers. They are to be seen any bright day flying around the moist earth in the vicinity of our wells, or nervously walking about on the muddy edges of some little pool or pond. If you will watch one of them you will soon observe it kneading and rolling up the clay with its mandibles into pellets to build a strange little cell for its young in the most peculiar and out- of-the-way place. You may at some time have found one of their domiciles attached to an unused garment in your cloak-room ; you have doubtless seen these
ELEMENTARY STUDIES IN INSECT LIFE
FIG. 54. A mud-dauber (Pelopceus cemen- tarius). XI1--
mud-daubers' homes pasted to the under side of your porches, around the barns, and not infrequently un- der the bridges of the highway. If you will break open one of these nests you will find, if the time is right, the developing form surrounded by spiders in a comatose condition; or if perchance the regular occupant is gone you will find the remnants of these same spiders in this little adobe structure.
The strength and prowess frequently displayed by these solitary wasps in securing their prey is often re- markable. They will frequently enter dark hay-mows and old garrets in quest of spiders for their young. The writer on one occasion observed one of these at- tempt to drag a good-sized ground-spider up the side of a church to a knot-hole in the weather-boards, where the wasp was constructing a nest. Laboriously and yet steadily did it go diagonally up the building, moving backward with its mandibles fastened in its load, until it reached an elevation of about three feet, when, its strength giving out, the wasp, spider and all fell to the ground. This operation was repeated three times be- fore darkness interfered with the insect's work for that day.
When these female wasps are ready to deposit their
SOLITARY LIFE
^
65
»'*
FIG. 55. Mud-daubers and their nests. From photograph. X "i .
eggs they prepare a nest, as it were, by digging a hole in the ground or excavating a cavity in some tree or partially decayed log or stem, or constructing a cell of mud or of wood pulp. Here they place the eggs singly, and proceed to capture the characteristic food for their young. These caterpillars, or whatever the prey may be, they sting in such a way as to stupefy. In this condi- tion the captives remain, to become food for the young
upon their appearance. — 5
ELEMENTAKY STUDIES IN INSECT LIFE
The actions of the parent in capturing this prey and placing it in a position in the nest as food awaiting the hatching of the egg, are among the most interesting observations to be made in the study of animal life. A number of remarkable instances have been recorded. One which will serve the purpose here, and which goes even farther in showing the use of tools among insects, was observed by Dr. S. W. Williston, of the University of Kansas, and is here given in his own language :
" Even the casual observer, to whom all insects are bugs, cannot help but be struck by the great diversity and number of the fossorial llymenoptera of the plains. Water is often inaccessible, trees there are few or none, and only in places is the vegetation at all abundant. A much larger proportion of insects, hence, find it necessary to live or breed in holes in the ground, than is the case in more favored localities. Especially is this the case with the Hymenoptera, great numbers and many species of which thus breed in excavations made by themselves.
" While packing specimens on an open space, uncov- ered by buffalo-grass, in the extreme western part of Kansas, the early part of last July, the attention of a friend and myself was attracted by the numerous wasps that were constantly alighting upon the ground. The hard, smooth, baked surface showed no indications of disturbance, and it was not till we had attentively watched the insects that we learned what they were doing. The wasp is a very slender one, more than an inch in length, with a slender, pedicellate abdomen; it is known to entomologists as Ammophila Yarrowi Ores. They were so numerous that one was distracted
SOLITARY LI1<K
67
68
ELEMENTARY STUDIES IX INSECT LIFE
by their very multiplicity, but, singling out different individuals, we were enabled to verify each detail of their operations. An insect, alighting, ran about on the smooth, hard surface till it had found a suitable spot to begin its excavation, which was made about a quarter of an inch in diameter, nearly vertical, and
FIG. 57. The tarantula-hawk (Pepsi's formosa), one of the giant wasps, which stores its burrows with tarantulas. From a photograph.
carried to a depth of about four inches, as was shown by opening a number of them. The earth, as removed, was formed into a rounded pellet and carefully carried to the neighboring grass and dropped. For the first half of an inch or so the hole was made of a slightly greater diameter. When the excavation had been car- ried to the required depth, the wasp, after a survey of the premises, flying away, soon returned with a large pebble in its mandibles, which it carefully deposited within the opening; then, standing over the entrance upon her four posterior feet, she (I say she, for it was evident that they were all females) rapidly and most amusingly scraped the dust with her two front feet, ' hand over hand,' back beneath her, till she had filled
SOLITARY LIFE 60
the hole above the stone to the top. The operation so far was remarkable enough, but the next procedure was more so. When she had heaped up the dirt to her satis- faction, she again flew away and immediately returned with a smaller pebble, perhaps an eighth of an inch in diameter, and then standing more nearly erect, with the front feet folded beneath her, she pressed down the dust all over and about the opening, smoothing off the surface, and accompanying the action with a peculiar rasping sound. After all this was done, — and she spent several minutes each time in thus stamping the earth, so that onlv a keen eve could detect anv abrasion
*.. » «/
of the surface, — she laid aside the little pebble and flew away to be gone some minutes. Soon, however, she comes back with a heavy flight, scarcely able to sustain the soft green larva, as long as herself, that she brings. The larva is laid upon the ground, a little to one side, when, going to the spot where she bad industriously labored, by a few rapid strokes she throws out the dust and withdraws the stone cover, laying it aside. Xext, the larva is dragged down the hole, where the wasp remains for a fe\v minutes, afterwards return- ing and closing up the entrance precisely as before. This, we thought, was the end, and supposed that the wasp would now be off about her other affairs, — but not so; soon she returns with another larva, precisely like the first, and the whole operation is again repeated. And not only the second time, but again and again, till four or five of the larva- have been stored up for the sus- tainment of her future offspring. Once, while a was]) had gone down the hole with a larva, my friend quietly removed the stone door that she had placed near the
70
ELEMENTARY STUDIES IN INSECT LIFE
SOLITARY LIFE
71
entrance. Returning, she looked about for her door, but not finding it, apparently mistrusted the honesty of a neighbor, which had just descended, leaving her own door temptingly near. She purloined this pebble and was making off with it, when the rightful owner appeared and gave chase, compelling her to relinquish it.
" The things that struck us as most remarkable were the unerring judgment in the selection of a pebble of precisely the right size to fit the entrance, and the use of the small pebble in smoothing down and packing the soil over the opening, together with the instinct that taught them to remove every evidence that the earth had been disturbed."
Coinciding with this are the interesting observations subsequently made by George W. and Elizabeth Peck- ham : " Just here must be told the story of one little wasp whose individuality stands out in our minds more distinctly than that of any of the others. We remember her as the most fastidious and perfect little worker of the whole season, so nice \vas she in her adaptation of means to ends, so busy and contented in her labor of love, and so pretty in her pride over her completed work. In filling up her nest she put her head down into it and bit away the loose earth from the sides, letting it fall to the bottom of the burrow, and then, after a quantity had accumulated, jammed it down with her head. Earth was then brought from the outside and pressed in, and then more was bitten from the sides. When, at last, the filling was level with the ground, she brought a quantity of fine grains of dirt to the spot, and picking up a small pebble in her mandibles, used it as a hammer in pounding them down with rapid strokes,
72
ELEMENTAKY STUDIES IN INSECT LIFE
thus making this spot as hard and firm as the surround- ing surface. (Fig. 58.) Before we could recover from our astonishment at this performance, she had dropped her stone and was bringing more earth. We then threw ourselves down on the ground that not a motion might be lost, and in a moment we saw her pick up the pebble and again pound the earth into place with it, hammer- ing now here and now there until all was level. Once more the whole process was repeated, and then the little creature, all unconscious of the commotion that she had aroused in our minds, — unconscious indeed, of our very existence, and intent only on doing her work and doing it well, — gave one final, comprehensive glance around, and flew away."
SOCIAL LIFE
73
CHAPTER V SOCIAL LIFE
For where 's the state beneath the firmament, That doth excel the bees for government ?
— Du Bartas.
So work the honey-bees, Creatures that by a rule in Nature teach The act of order to a peopled kingdom.
— Shakespeare.
* f •*+-
ITIIIN reach of almost every school- house in the land then1 exists a colony of bees. Every school-In »v
t/ «/ i'
and school-^irl knows the honey- bee, and many of them have be- come familiar by experience with some of its traits. The busy bee has method in its business, and its mode of life is worthy of our careful study.
The Colony. — A colony, hive or household, consists of from twenty-five thousand to thirty-five thousand worker bees, a few hundred drones, and a queen. The greatest number of bees are present in the hive during the honey-gathering season, when their services are must needed, and the least number of bees will be found in the hive during the winter months, when the fewer the mouths there are to feed, the longer will last the food. It frequently happens that during the honey season the number exceeds thirty-five thousand, and in the
74 ELEMENTAEY STUDIES IN INSECT LIFE
winter the hive may dwindle far below twenty-five thou- sand and still retain its organization.
In every hive there is a form of government, political you may call it, but uniform throughout the whole realm of the bee world. The same offices exist in all and the functions of each office are constant.
The Queen.— - The most important personage in the beehive is the queen, whom people, before her true function was known, called the " king bee," on account of her size. From neither of these terms must it be
FIG. 59. A queen bee. X 2.
inferred that she is in any sense a despot, for, though the most important and attractive personage in the hive2 she is more frequently ruled than ruler. She receives, however, every attention that can be bestowed upon her by her attendants ; and well may they caress her, for around her centers the existence of the hive.
The queen is the only fully developed female in the hive. She is the mother of the entire colony; she lays all the eggs, from which hatches every bee that exists within the hive. The eggs which she lays bring forth workers, queens and drones in accordance with the well-
SOCIAL LIl-'K <.)
organized plans of this government. The eggs which produce queens and workers are in nowise different. They are spoken of as fertile eggs ; that is, they con- tain within them the male element. The eggs which are unfertilized bring forth drones. There is no evi- dence, however, that drones cannot also be produced from fertilized eggs.
The eggs hatch in about three days after being laid. The newly hatched larvse are fed by nurse bees with a lactic fluid which is secreted in a portion of the alimen- tary canal of the nurse bee. All are fed with this until about three days old, when the bees intended to become workers and drones are given a substance familiarly known as bee-bread. Those larva1 which are to make queens are fed throughout their whole growing period with this lactic fluid from the nurse hees ; a substance which, on account of its being the sole nourishment of the queen not only during her period of development but likewise throughout her whole existence, is commonly called " royal jelly." From this it will be seen that the only difference between the queen and the worker is in the quality of the food given to them in their growing stages.
The presence of a queen is necessary to the existence of every colony, and should the queen be removed fmin any cause the workers at once set about to develop an- other queen by continuously feeding a newly hatched larva with this royal jelly. The queen spends about three days in the egg stage, six in the larval, and seven in the quiescent or pupal stage, before appearing as an adult.
The queen cells are houses in which the queens are
ELEMENTARY STUDIES IN INSECT LIFE
reared, and are different from those in which the worker and drone bees are reared. Figure (>0 shows the large queen cells extending out from the comb, not unlike a peanut in shape. These, it might be added, are cells which have been constructed in an artificial way ; that is, when the bees are forced to produce a queen out of the regular swarming season. At the regular season of
FIG. 60. Brood corub, showing queen cells protruding.
the year, when the bees give regular attention to rear- ing a few queens, the queen cells will be found usually at the ends and bottom of the comb.
These young queens will become fertile and begin laying eggs when they are ten to twelve days old. An active queen will deposit from two to three thousand eggs daily. She is of great service to her colony for two years, and may live still longer. The queen is in- tensely jealous, and will brook no rival in her domain. The appearance of another queen is a signal for a battle, which generally terminates in the death of one. It is on such occasions only that queens use their stings.
SOCIAL LIFE
77
Should a newly hatched queen discover another queen cell, if not prevented hy the worker bees she will imme- diately tear open and kill the young queen found therein. The Drone.— - The drone is developed from the unfer- tilized eggs, placed in cells >omewhat larger than worker
FIG. 61. A drone bee. X 2.
cells. These develop in nix nit twenty-four days, remain- ing three in the egg, six in the larval, and fifteen in the pupal stage. These are reared in large numbers during the swarming season, in order that the fertility of all queens may be assured. The drone, as is generally known, is the male, and has no tools for collecting- honey or gathering pollen, and is therefore, after the swarming season, looked upon as a useless member of society, only to be stung out of the hive. This the worker bees hasten to do as soon as his period of use- fulness is past.
The Worker.— - The worker is the bee familiar to all of us ; the one respected for its business air as well as its powers of defense. Workers mature in about twenty- one days, spent in the following stages: three days in the egg state, five in the larval state, and thirteen
78
ELEMENTARY STUDIES IN INSECT LIFE
FIG. 62. A worker bee. X 2.
in the pupal stage. The worker, as its name implies, is the laborer of the hive. It gathers all the honey, the pollen, the propolis or bee-glue, carries water, secretes wax, builds comb, pre- pares food, nurses the young brood, defends the hive, and cleans house. The workers are busy night and day. In a well-regulated colony the division of labor is as follows: The first work the young bee performs after it is two or three days old is to prepare food and feed the larva? in the cells ; its next duty, when ten or twelve days old, is to secrete wax and build the comb ; at about twenty days old it becomes a honey-gatherer from the field. The young bee is easily known by the pale color and lack of strength ; in a few days it becomes stronger and is well covered with hair ; the aged worker is known by its tattered wings and bald body. The average life of the worker is about five weeks. If you will sit somewhere between the hive and the bee pastures you will fre- quently see the old bald bees falling by the wayside ; their strength is ex- hausted and their wings are no longer fit for duty.
Bees, like people, have disposi-
Fio. 63. Secretion of
tions; they have moods. These dis- wax scales. (Enlarged,
from "Illustrirte Bie-
positions seem to be transmitted nen-zeitung.»)
SOCIAL LIFE
79
ant
FIG. 64. Head and mouth-parts of worker bee. Eye, compound eye ; ant, antennse ; Ib, labium ; md, mandible ; g, maxilla ; Ip, labial palpi ; pg, paraglossa ; /, tongue or glossa.
from generation to generation, so that certain tees have to-day the reputation of being kind, gentle and tractable, and others irrita- ble, easily disturbed, and ever ready for a fray. They are characterized as industrious and frugal. They are not, however, at all times possessed of integ- rity, for if the nectar from the flowers becomes scarce they are wont to look about for some weak neighboring colony to rob of its small and feebly defended store of sweets. Have you ever seated yourself by the side of a colony and watched the comings and goings of the bees ? Have you seen the pollen baskets, well laden, being taken into the hive ? Have you ever seen the young ones go forth to establish themselves in housekeeping? These are some things which you must see in order to appreciate them ; so arrange with some beekeeper in your neighbor- hood for a visit to his apiary. He, I am sure, will be only too glad to act as your instructor during your visit. When there examine the honeycomb proper, and the brood comb, containing workers, drones, and queens. Make a drawing of the shape of the mouths of each one of these cells. Is the shape of these mathematically accurate ; that is, is each of them a true hexagon ?
Swarming.- - The young bees are hatched in such num- bers in the spring that the old hive cannot longer accom- modate all of them. This, together with the mortal jeal-
80
ELEMENTARY STUDIES IN INSECT LIFE
ousy of the queens, makes the es- tablishment of a new home neces- sary. On some bright spring morning, therefore, in every well- established colony there arises a great commotion, attended by un- nsnal bnzzing sounds. The bees begin to pour forth in an impet- iion s current. The crowd of merry hummers, circling, fill the air witli an indescribable rustling murmur. More keep crowding through the doorway, until the air is darkened by a large and giddy circle of bees. In a little while the center grows darker, and this in the vicinity of some branch upon which all pour down in the same fashion that they left the hive. Somewhere within this living mass is the queen of the hive. Here they " settle " to await, we have reason to believe, the return of the couriers sent to spy out the land. Good reports being received, they are up and away to the place sought out, The would-be emigrants, evidently aware of the contingencies of such a journey, make full preparations by filling their honey-sacs before leaving the old hive. This amount of food will by economy furnish a week's subsistence.
This is " swarming," and you will readily see that this procedure is in the interests of the race; for if all lived in one household, however large it might bo
FIG. 65. A newly settled swarm. Photographed from life. (Courtesy of the Cen- tury Co.)
SOCIAL LIFE
81
«v WW,,
FIG. 66. Hiving a swarm. Photographed from life.
and however numerous its occupants, should that house meet destruction nothing would be left to tell the tale or replace the loss. But with the distribution of homes throughout the land, the likelihood of a common catas- trophe is much lessened if not wholly improbable.
Ants. — " If the statesman or the philosopher would study a perfect communistic- society, let him throw away his histories of poor human attempts and go and study thoroughly the nearest ant-hill. Then- he will find no love for friend or wife or child, but a love for every one. There everything is done for the good of the whole, and nothing for the individual. The state makes wars, provides food for all, cares for the children, owns all the property. lie will find no complaint against the existing condition of society, no rebels; but the fate of each one is determined bv the accident
°4 ELEMEXTAKY STUDIES IN INSECT LIFE
of birth, and each takes up its work without a murmur. He will find that this perfect commune has developed courage, patriotism, loyalty, and never-failing industry ; but he will find also that war, pillage, slavery, and an utter disregard of the rights of other communities and individuals, are as prevalent as they are among our own nations, where selfish private ambition has held sway so long.'' (COMSTOCK.)
Similar to the economy of the beehive, the workers are the most active and interesting forms within the colony. Like the worker bees, the worker ants are unde- veloped females, and, as their name implies, they do all the work. This consists of building and defending the nests, caring for the young, and collecting food. They not only defend the hives, but they likewise carry on wars of conquest, frequently going forth to capture slaves. Some species of ants make a business of raid- ing the nests of other ants and bringing away the larva? and pup* to their own nests, to be reared and kept as slaves. So far has this gone in the case of some species that the slaveholders have been dependent, upon their slaves so long that they are unable to carry on the work without the aid of slaves, and become helpless when the slaves are removed. It would seem, too, that these slaves have been slaves so long that they have be- come such by instinct. Huber placed several of the slaveholders by themselves, where nearly all of them helplessly starved though plenty of food wras accessible. A slave was then introduced. This slave immediately set to work constructing a nest and administering nour- ishment to those still alive, thus saving its stupid mas- ters from death.
SOCIAL LIFE
83
Ants also show their ingenuity in caring for herds. This system of stock-raising and dairying can he ob- served by any sharp-eyed student. The herds of the ants, or, as they are sometimes called, the ant cows, are the plant-lice or aphids, — such forms as molest your pan- sies. These it is that are cared for by the ants. In
FIG. 67. "Mud shed" built by ants for sheltering their "herds" of aphids. Photographed from life by M. V. Slingerland.
some cases they show great forethought in taking the eggs of these aphids into their homes and caring for them, rearing the aphids and carrying them out and placing them in green pastures. The aphids reward the ants for this attention by giving them a s\veet substance generally called honeydew. This substance appears in minute drops upon the back of the aphid. It is fre- quently excreted in quantities sufficient to coat the leaves
84 ELEMENTARY STUDIES IN INSECT LIFE
of branches below the aphids. Sometimes this fluid is noticeable on the stone walks above which there are trees in which are plant-lice. This method of ants con- ducting1 their farming system the student can observe for himself. Whenever ants are found going- up and down a tree, it may be taken for granted that they are going and returning from aphid pastures. The redbud tree is a favorite with some species of aphids. A branch of this upon which aphids and ants are found can be removed and the stem placed in a vessel containing water. The leaves will remain green for some time and the relations existing between aphid and ant can be observed.
If the student has not already discovered it, his at- tention is now called to the fact that there are three classes of ants in a colony : males, females, and workers. The first two are winged and the workers are wingless. During the summer it will be possible for the student to observe a number of ants coming forth from the hives and taking flight. Many of the colonies of ants are doing this at the same time. It is during this flight that the female, commonly called the queen, is fertilized. She drops to the earth, tears off her wings, these being no longer required, and endeavors to secure a place to deposit her eggs. She is sometimes taken into a colony of her own species, and sometimes she starts a new colony from the eggs which she lays. Comstock has shown in a series of interesting experiments that it is possible for a queen of the carpenter ant1 to build her cell, lay her eggs and bring forth the first of her brood without taking any food whatever. The cell she builds
^Camponutus pennsylvanicus.
SOCIAL LIFE
85
is a closed one, and contains no store of food excepting what may be within the body of the queen. The term queen, as in the case of bees, is a misnomer, since these queens do not rule 1m t are simply the mothers of their respective colonies. The queen ant differs from the queen bee in that she is not jealous, and a number of queen ants may be found living peaceably within the same hive.
The ant-eggs are small and not easily observed. The larvae are white and legless. Those oblong egg-shaped bodies which are frequently mistaken for eggs are the pupa-cases or cocoons from which the adults, with the tender assistance of their nurses, will emerge.
Wasps. — Wasps, in their habits, are of two classes,— social and solitary. Of the former, the hornets * and yellow- jackets2 are the best known. The hornets build large spherical homes from the weather-beaten wood fibers which they have scraped off, chewed up into a pulpy mass, and then plastered out into thin layers with their deft mandibles. Boys and girls who have been brought up in wooded countries are familiar with the appearance of the large spherical hornets' nest de- pending from some tree or bush. In the fall of the year these deserted nests are sometimes gathered and placed in the stables to repel, as farmers believe, all manner of diseases from the horses kept there. The sting of these wasps, called into use upon the slightest provoca- tion, is much to be respected. Though these insects are somewhat warlike, when approached quietly and cautiously one may have the privilege of standing
lVespa sp. -Polistfs .--p.
86
ELEMENTARY STUDIES IN INSECT LIFE
close by and watching the workers come with their little pellets of wood-pnlp and spread the material skillfully and frugally over the place desired.
The yellow- jackets build nests of the same material, but construct them of only a single layer of cells. They
FIG. 08. Yellow-jackets (polistes sp.) and their nests. From a photograph. y2.
locate them generally in some sheltered place, such as under a large flattened rock which lies loosely upon other rocks near the ground, or under a porch or simi- larly sheltered place.
The life history of these two kinds of wasps is much
SOCIAL LIFE
87
the same. In the fall of the year the fertilized queens hibernate in the crevices and sheltered nooks. In the spring they look about for suitable nesting-places ; with wood-pulp gathered by themselves they build up the first layer of cells. The queen deposits an egg in each of these cells and feeds the newly hatched grubs a week or ten days until the} pupate. Ten days later the perfect wasps have come out of these cells and arc ready to take up their share of the re- sponsibility in the work of the colony. These first wasps are workers. The work of gathering the wood- pulp and moulding the same into cells now devolves wholly upon these workers. The queen devotes her time and attention to depositing an egg in each of the cells. The colony con- sists of the queen and an increasing number of workers, until the late summer, when drones are developed. As
FIG. 69. Hornets' nest. Drawn from nature by Miss M. E. Wise. £
88
ELEMENTARY STUDIES IN INSECT LIFE
the cool weather announces the approach of winter, the workers and queens desert the hive, leaving- the help- less drones and unat- tended young to per- ish. The workers wander about until killed by frost. The queens alone seek some sheltered place to spend the winter.1 The social wasps are predaceous. They feed their young upon insects which they have masticated. Adults seek also the nectar of flowers, the juices of fruits, and the honeydew of plant-lice.
The queens, drones and workers are simi- lar in color. The queens are larger than the workers. The drones do not sting, but unfortunately their close resemblance to the hostile and much-dreaded workers leads us to repel the advances of all alike. The number of individuals existing at one time among these social wasps is often quite great, but there are not so many species as there are among solitary wasps.
1 Iii Brazil there are perennial communities of wasps founded by swarm after the fashion of bee colonies. (Von Ihering.)
Fie. 70. Hornets' nest; one side removed, to show arrangement of combs within. Drawn from nature by Miss M. E. Wise.
INSTINCT. s'!
CHAPTEE VI
INSTINCT
THE remarkable actions of the wasps related in the foregoing chapter naturally give rise to the question, What prompts and directs snch actions ? Activities of this class are common ti> all, or nearly all, of each spe- cies possessing snch traits. Each works after its own manner and in a way that is uniform for each specie^. Some of these acts occur before the insect is old enough to be taught. Such acts are said to be instinctive. In- stinctive acts are for the most part, if not altogether, performed without reflection. Insects do certain things in a certain way. Their actions seem to accord with their natural surroundings, but should their environ- ments be changed their actions are not changed accord- ingly. For instance, a certain wasp provisions its nest with a large grasshopper. The wasp drags the grass- hopper along by one of the antenna1. When the antenna' are cut off, the wasp looks around the head, and finding no antenna1, gives up the task and flies away. It never occurs to the wasp to take hold of a leg and proceed. An excellent example is the case <if the trap-door spider, not itself an insect, but one of the insect allies. This trap-door spider makes its home in tubular burrows beneath the surface of the ground. It covers its tube with a hinged trap-door. When the spider is pur- sued it seeks refuge within its home, closing the trap- door after it. Where these spiders dwell the ground
90 ELEMENTARY STUDIES IN INSECT LIFE
is carpeted with moss, so in making this trap-door the spider covers it with moss, — an act for protection, for when the door is closed no trace of the spider's hiding- place is visible. If in the absence of the spider the moss be removed from the door and the earth bared over con- siderable space around the door, the spider will upon her return carry moss across the open space and re-cover her trap-door, making this not a protection but the most conspicuous object on the situation. That which prompts the wasp to drag the grasshopper only by the antenna?, and which causes the spider to cover its trap- door with moss, is termed instinct. Had the wasp and the spider shown their ability to cope with changed con- ditions, their actions would have been due to reason. These instinctive actions are those which are performed without learning or practice.
Actions of the Newly Born. — Instinct is, then., best il- lustrated by the actions of the newly born forms. Young wasps, just out of the pupa-case, though limp and almost helpless, when disturbed protrude the sting and move the abdomen about in various directions, in their en- deavor to sting the disturber. They seem to perform these acts as perfectly as do the mature wasps. Sting- ing, then, is a purely instinctive act. The young cater- pillar's first act (p. 14) after leaving the egg is to turn around and eat the egg-shell. All the young caterpillars of the swallowtail butterfly do this. Not one of them before doing this has had an opportunity to be taught this act. They do it instinctively. The origin of in- stinct is an open question: some authorities believe that the act of one individual repeated many times be- comes a habit, and that this habit can be transmitted
INSTINCT 91
from generation to generation until it becomes an in- stinct; that is, instincts are "inherited habits." Other authorities believe that instinct is due to natural selec- tion. Insects with certain habits favorable to their exist- ence live to reproduce in kind, while those without these characteristics perish before they have brought forth young. For instance, according to this view, the earlier generations of wasps did not all sting. Those that did not sting were more liable to succumb when attacked, while those who used their stings vigorously survived, and lived to beget forms with a tendency to sting. In time the stinging wasps were the only ones left, and among them the most violent stingers would still be the most liable to perpetuate the species.
Acts of Mature Life. — Among the best examples of in- stinctive acts of mature life, stand the interesting habits of insects. The making of homes, the homing instinct, as already noted, in the case of bees and wasps (pp. 79, SO), the waging of wars and the making of slaves among ants (pp. 81, 8:2), are examples of this class of instincts. It must be conceded that every individual is not likely to perform these acts in identically the same manner, and further, that there is a possibilitv of action somewhat intelligent while in the performance of these instinctive acts of mature life. It is not at all likely that every Ammophila (p. G8) makes use of a pebble in the work of storing food for the sustenance of offspring. To those that do this, intelligent action must be accredited. Such insects have profited by the experiences of their own lives.
Acts Associated with Reproduction.— - The construction of homes and the storage of food for their voung are the
92
KLKMKXTAKY STUDIES IN INSECT LIFE
hi<>-hest forms of insect instinct in this class. Such in-
o
stinctive acts have been fully discussed in the previous chapter. To the same class of acts belongs the care with which certain insects, such as butterflies, deposit their eggs in the vicinity of the natural food plant of their offspring. The most wonderful of all is that of the Pronuba moth, discussed elsewhere (p. 112). The
FIG. 71. Female wasp (Sphes speciosus) carrying a cicada to her burrow, an instinctive act associated with reproduction. Natural size. (After Kiley.)
Pronuba moth gathers the pollen and carries it to the proper place in order that the yucca blossom may be fertilized to furnish succulent seeds for the young which is to hatch from the egg she places in the ovary of the yucca flower. This is an instinct most wonderful in its perfection, and certainly as obscure in its origin.
Limitations of Instinct. — Instinct has certain bounds, and when activities have passed beyond these bounds they become something more than instinct. A wasp
INSTINCT 93
that was unable to drag away the grasshopper because it could not find antenna1 to take hold of, and the spider that made its subterranean home conspicuous by cover- ing- it with moss, are examples of the limitation of in- stinct. The activity of certain insects seems to go be- yond the bounds of instinct and enter the realm of thought. Such insects are credited with intelligence.
Instinct and Reason. — A colony of bees finding a dead snail within their hive, endeavored to drag it out. This \vas an instinctive act, since it was instinctive with them to repel all intruders, but when they were unable to re- move the snail thev at once covered it over with wax
</
and hermetically sealed it in its position. This was no longer an act of instinct, but an act of reason. It is evident here that the nerve centers acted independently of any past experience; that is, there was reason shown and intelligent action manifested.
The following may be considered the chief instinctive acts : Choice of food, partaking of food, capture of prey, building of homes or nests, storing provisions cither for themselves or their offspring, spinning cocoons of a defi- nite form. When a customary mode of performing these instinctive acts is changed, the change is likely to be due to intelligent adaptation to new modes of life. Insects which for many generations have built their nests in a certain kind of places, such as under rocks, forsake these places and choose better adapted places under the eaves of houses. Of all the intelligent acts the one given elsewhere (p. US) stands among the first ; that is the case of Ammophila using a stone to pound the earth over her nest.
ELEMENTARY STUDIES IN INSECT LIFE
CHAPTEK VII
THE MUTUAL RELATIONS OF PLANTS AND INSECTS
"Insects have been inhabitants of land plants since their origin in early Paleozoic ages, and the mutual relations of plants and insects have ever been intimate." — Cope.
Plants and insects illustrate interdependences. In- sects rely upon plants for nourishment; plants depend upon insects for proper maturation of seed. Some in- sects are injurious to certain forms of plant life. Such feed upon the foliage, or live within the body of the plant. Some insects seek their food within the nectaries of flowering plants, and in so doing advance the welfare of the plant. To this latter class we will con- fine our study.
Near the close of the eighteenth century Sprengel first pointed out the useful purposes of colors, scents and singular forms of flowers. He brought forth the facts that nectar-producing plants have the nectar so situated as to be protected from rain, yet easily accessible to in- sects. He concluded "that the nectar of these flowers is secreted for the sake of insects, and is protected from rain in order that the insects may get it pure and un- spoiled." His first observations, then, were that plants exist for the benefit of insects. Later, however, he made additional discoveries, which led him to believe that many flowers are absolutely incapable of being fer- tilized without the aid of insects, and therefore the secre- tion of nectar and its protection from rain by the plant,
ri.AXTS AND INSECTS
and the bright color of the corolla, are contrivances made by the flower in its own interests; that is, to accomplish the fertilization of the flower. Such flowers are, he says, fertilized by some one species of insect or by sev- eral species, and the insects in approaching the nectar brush pollen from the anthers with various hairy parts of their bodies and convey it to the stigma. Sprengel did not, however, perceive the advantages the plant gains, further than the mere formation of the seed. Knight and Herbert, two later workers, perceived, in a degree, the effects of this fertilization of plants by in- sects upon subsequent plant generations.
It remained for Darwin to place the almost forgotten work of Sprengel upon a broad basis. " jSTo organic- being fertilizes itself for a perpetuity of generations, bnt that a cross with another individual is occasionally, perhaps at long intervals, indispensable." Darwin fur- ther showed that, in higher forms and the greater num- ber of lower animals, the sexes are separate ; that those forms having the function of the two sexes present in the one animal, even these pair regularly. Breed- ers of animals and cultivators of plants have found that continued in-and-in breeding deteriorates the stock, while crossing with another breed or another strain of the same breed increases the strength and productiveness of the offspring.
Since continuous close-fertilization is detrimental to the interests of the plants, Mature has brought about contrivances to prevent such recurrence. She does this in two ways: (1) by modifications in the structure of the flower so that the pollen cannot possibly fall upon the stigma of its own pistil; (2) in other plants, whose
96
ELEMENTARY STUDIES IN INSECT LIFE
pollen does fall upon its own stigma, by rendering this sterile to its own ovule but fertile when transferred to the flower of another variety of the same stock. Briefly and in a general way, this sums up the advance of our knowledge upon this interesting subject. Many subse- quent investigations have elaborated these principles by the detailed study of various forms of flowering plants.
cP
P
FIG. 72. Enlarged section of a Bartlett pear flower : sf, style ; sp, sepal ; /, filament ; a, anther ; s, stigma ; p, petal ; d, disk ; ov, ovule. (After Waite.)
Plants whose Flowers are Sterile to their Own Pollen but Fertile to Pollen Brought from Other Plants of Same Species.
More than fifty species of plants have been found to be partially or wholly sterile to their own pollen, but fer- tile to pollen transferred from other plants of the same
1'LAXTS AM> I.NSKCTS
97
kind. The apple and pear belong to this group. Ac- cording to Wai re, cross-fertilization is an important fac- tor in the production of pome fruits.
The pear blossom is a typical flower, composed of five brownish-green calyx lobes, five white or pinkish petals, numerous stamens, a five-celled ovary, and live styles and stigmas. The pear forms at the base of the blossom. There is within the blossom a yellowish-green saucer-shaped disk, upon which the nectar is secreted. Extending from this disk to the ovary are five styles. Within the ovary are the ovules, which upon proper fer- tilization become seeds. The ends and a strip down one
FIG, 73. Buds of Bartlett pear. (After Wuite.)
side of the green styles are rough, caused by fringe- like projections for facilitating the reception and re- tention of the pollen grains. The stamens terminate in small roundish bodies, termed anthers. The four-celled anthers, when mature, split, allowing the pollen to escape —7
ELEMENTARY STUDIES IN INSECT LIFE
in two masses as though the anthers were two-celled. This pollen as well as the nectar serves to attract bees and other insects. The bright showy petals proclaim to the insects the location of the nectar.
FIG. 74. Cluster of Bartlett pear blossoms— natural size. From a photograph. (After Waite.)
When a bee visits the flowers the rough stigma brushes from the insect's hairy coat some of the pollen which ad- hered to it while seeking nectar in other trees, and if these trees were another variety this blossom is then cross-pollinated. The pistils mature (that is, become ripe, to receive the pollen) two or three days before the
PLANTS AND INSECTS
FIG. 75. Flower of Bartlett pear— natural size. (After Waite.)
pollen escapes from the anthers of the same flower. The stigma often extends through the petals before they are
fully open, thus offering the possibility of pollination from some earlier blossoming variety, - another way for cross-fertili- zation to occur.
The process of fecundation Waite describes : " Soon after its protrusion the stigma se- cretes a sugary fluid, often in sufficient quantity to be quite perceptible. In this the pollen grain readily germinates and throws out a slender, thread-like tube, which grows downward into the pistil and through specially soft tissue, adapted to its growth, until it reaches the ovules. Here it enters an opening in the two outer coats of the ovule and conies in contact with the germ-cell, or egg- cell. A number of inter- esting and complicated changes now take pla.ce natural size, in the protoplasm of this cell and in the end of the pollen tube. A part of the con- tents of the latter actually passes through the cell-walls into the egg-cell, which, un- der this stimulus, immediately begins to showing only the <>T< ,w and divide, ultimately developing
five pistils— nat- '.
into the germ of the seed. This stim-
FIG. 76. Bud of the Bartlett pear, with the petals re- moved, showing the incurved stamens —
100 ELEMENTARY STUDIES IN INSECT LIFE
ulus not only causes tlie seed to grow, lint also the surrounding1 fruit, the latter depending upon seed development in most cases. In some cases, how- ever, the growth of the pollen tube may help to
FIG. 78. Bartlett pear cross-pollinated with the pollen of the Easter pear.
stimulate the fruit to develop independently of the fecundation of the ovule, which may or may not after- wards result, and this probably accounts for the fact that many little fruits begin to develop, but afterwards drop off."'
PLAXTS AXI) IXSKCTS
101
"\Vaite lias conducted experiments in the cross-fertili- zation of pears and apples for several years, liy placing sacks over the buds to prevent the introduction of foreign pollen, by removing the stamens before ripe and polli-
•£•_
FIG. 79. Seeds from en>"ci] and from self-pollinated Bart- lett pears : a, from crossed pears; b, from self-pollinated pears. (After Waite.)
natiiiii' the pistils with pollen from other va- rieties. The actions of insects towards the blossoms were al~" noted. His conclu- sions in part are: Some of the common varieties of pears re- quire cross-fertiliza- tion; some varieties are capable of self-fertilization; pollen is transported from tree to tree bv bees and other insects and not bv the wind; bad weather keeps away insect visitors and hence materially affects the fruit yield; self-fecundated pears are deficient in seeds, and
FIG. 80. Self-pollinated Bartlett pear.
102 ELEMENTARY STUDIES IN INSECT LIFE
FIG. 81. Baldwin apple cross-pollinated with pollen of the Bellflower apple. (After Waite.)
FIG. 82. Large specimen of self-pollinated Baldwin apple.
PLANTS AND INSECTS
103
FIG. 83. Small specimen of self-pollinated Baldwin apple. (After Waite.)
the seeds produced are usually abortive. The crosses are well supplied with sound seeds; the typical fruit and in most cases the finest specimens are from crosses. Accordingly, to secure the best results not only should an ample number of bees be placed in
FIG. 84. Section of an apple blossom. (After Waite.)
104
ELEMKXTAKY STUDIES IN INSECT LIFE
the orchard to insure' the visitation of the blossoms, but the different varieties of each fruit should be placed promiscuously throughout the orchard in order to facil- itate the work of cross-fertilization.
Plants whose Flowers are so Constructed as to Prevent Self-fertilization. — A papilionaceous flower is an exam- ple of a blossom so constructed as tn prevent the falling of the pollen upon the stigma of its own pistil. The alfalfa blossom is an example of this class. Its structure and component parts are illustrated in Figure 85. It will be seen that the stigma of the ovary is higher than the pollen-producing anthers, so that the grains of pollen may all drop to the base of the flower and the ovule go unfertilized; such being the case, no seed would be formed. Small forms resembling seed might be found within the ovary at maturity, but these, not being fer- tilized, would not germinate.
From the shape and size of the alfalfa blossom, it is not probable that cross-fertilization could be safely accomplished by means of currents of air.
It becomes evident, then, that outside agencies must be called upon, and the plant must provide for these agencies. The agents in this case we find to be insects, and the reward offered by the plant for favors rendered is a sweet drop of nectar; that is, the flower in an en- ticing way places a tempting sip of nectar in such a position that when the insect has favored the flower with a few grains of pollen unconsciously brought from an adjoining flower and just as unconsciously left, the cov- eted sip may be enjoyed. It is evident, however, that the first flower visited will not be cross-fertilized.
The location of the coveted nectar at the base of
L'LAXTS AM) I.XSKCTS
105
the flower, the action of the tongue of the hee and the work of the hairs under the head and upon the In-east in placing the pollen upon the stigma, are shown in Figure Mi and also in Figure S,~>, !>.',. The tlo\vor gives material aid, hv causing the stamen- and pistils to spring up and strike the insect.
e.
FIG. 85. a, cluster of alfalfa with bee feeding, b, bee thrusting proboscis into flower: 1, vexillum ; 2, alas; 3, carina ; 4, reproductive organs (gametangia) ; ,3, calyx, c, alfalfa bloom with vexillum torn off : •?, ala> ; a, carina ; 4, reproductive organs (gametangia) ; .1, stigma ; ff, anthers ; 7, calyx, d : 1, filament ; ?, anther ; •V, style; i, stigma, e, pistil: 1, ovary: :', style : .V, stigma : /, ovules. ,/, highly magnified pollen grains.
A part of .Miiller's observations upon this point are: If in a YOUUO- flower we cut through the claw of the carina, the column springs upward to some extent, carry-
106 ELEMENTARY STUDIES IN" INSECT LIFE
ing with it the carina and altv. If in another unexploded flower we carefully cut through one of the digitiform processes of the ala1, the parts remain motionless ; but on cutting the processes of the other side, explosion at once follows. The pouched processes of the carina (Fig. 85, 1)3 and cS} are thus sufficient to hold the column down without the aid of the processes of the alir (c.J) ; the alii' alone are not sufficient to hold the column down when the carina has been cut. Explosion can therefore be effected equally well by separating the anterior pouches, by separating the digitiform processes, or, filially, by depressing the a la? and carina.
If an insect inserts its proboscis in the middle' line between the anterior pouches and the digitiform processes, or if it stands upon the ala? and thrusts its head in the middle line
FIG. 86. Pollination of alfalfa flower lmdei' the Vexilluill, ill by bee. See fig. 64 for honey-collecting
tools of bee. either case explosion fol-
lows. The stigma (c5) projects beyond the anthers, and therefore is the first to strike the under surface of the bee's body or proboscis ; an instant later the anthers come in contact, dusting it with fresh pollen. The first flower that the insect visits is, of course, not cross-fertilized, but as the bee withdraws from the flower, self-fertilization inevitably occurs. Self-fertilization is undoubtedly efficient, for Hildebrand has shown that flowers which wither unexploded when insects are ex- cluded produce seed by self-fertilization. The same au-
PLANTS AM) INSECTS
107
thor finds two imperfections in the mechanism. One is the possibility of the insect securing the nectar without exploding the flower; the other is that the flower contin- ues to secrete honey after it has been fertilized.
A large number of rep- resentative matured pods were gathered from an al- falfa field less than one- half mile away from a large apiary, and a like number from another field of much the same soil, and practically under like con- ditions as the first field, ex- cept that the second field was situated twenty-five miles away from a colony of bees. No bees were ob- served in the field, and the character of the surroundings, there beim;1 no timber or probable living-places, was such as to preclude the possi- bility of wild bees in the vicinity. The pods from each locality were carefully opened and the number of seeds in each counted. In the field near the apiary the aver- age number of seeds in a pod was found to be .">..") X; seeds plump; pods numerous in cluster; pods having several spirals. In the other field the average number of seeds in a pod was .'5.:;,'); seeds in at least one-third of the pods were small and shriveled ; pods few in clus- ter; short, with but few spirals. The seed crop of the first field, on this basis, could be estimated at two-thirds greater that that of the second field.
FIG. 87. The many-flowered umbels of the milkweed. Photographed by W. C. Stevens.
108 ELEMENTARY STUDIES IN INSECT LIFE
Plants with Special Adaptations for Bringing About Cross- fertilization. — The milkweed family1 illustrates one of the many wonderful designs brought about by plants to in- sure cross-fertilization. The milkweed blossom is to be considered one of our highly specialized forms, and the high degree of development is due in a great measure to
FIG. 88. Entire flower of the milkweed (Asclepiodora viridis). Enlarged. a a, location of corpusculum ; d, longitudinal slit which separates the anthers, and into which insect draws its leg ; e, cucullus ; /, petal ; fir, sepal.
the actions of insects. The flower structure' must be understood before the work of the insect can be appre- ciated. The blosstan used to illustrate the arrangement of the parts is that of Asclepiodora v'uidls, or green milkweed. The five minute sepals (Fig. 88) are sit- uated beneath and alternating with the five well-devel- oped petals. By bending these downward as in the fig- ure, the inner mechanism can be more easily observed. Five hollow, fleshy, leaf-like organs immediately within, are attached to the central column. These arc termed collectively cuculli, or singly cucullus. (Fig. 88.) This fleshy column is made by the union of the five staminal filaments, each bearing at its upper end an
lAsclepiadacecv.
IT. A NTS AM) IXSKCTS
109
anther. The antliors lie close around the central stigma, disk, each anther being sepa- rated from the other by a longitudinal slit (Fig. 88, d} formed by the margins of flic anthers being extended
FIG. 90. Two pollen-masses (pollinia) joined by their bands (retinacula) to their central body (corpusculum). The frag- ment hanging down from the central body between these two pollen-masses is part of a leg of an insect which had been caught in the wedge-shaped slit in this body, and which had liberated itself by breaking off and leav- ing part of its leg fast there- in. Greatly enlarged. Photo- graphed by \V. C. Stevens.
Fin. 89. Longitudinal section of milkweed, a, corpusculum ; <7, slit between anthers ; n, pollen-mass (polliniuin) in normal position within flower.
ont perpendicularly as a slight triangular membranous expan- sion. Each anther bears two pollen-masses. Each of these masses is called a pollinmm. Hands or retinacula unite each polliniuin, to a dark central body, the corpusculum, situated at the top of the slit. The cor- pusculum is hard, horny, and upon examination is found to he grooved longitudinally. (Fig. DO.) This wedge-shaped iM'oove lies in line with the slit between the anthers. The lower part of the slit between the anthers is wider, and leads up into tin1 so-called stigmatic
110
ELEMENTARY STUDIES. IN INSECT LIFE
Fir;. 91. Honey-bee caught in entrapping slit of milkweed blos- som. Photographed from nature by W. C. Stevens.
FIG. 93. Moth caught in sev- eral flowers of milkweed. One leg has been broken off in its struggle to free itself. Photo- graphed from nature by \V. C. Stevens.
FIG. 92. Cabbage butter- fly held fast in milkweed blossom. Photographed from nature by W. C. Ste- vens.
FIG. 94. Honey-bee caught in several blossoms of milk- weed. Photographed from nature by W. C. Stevens.
PLANTS AND INSECTS 111
chamber. The cuculli secrete abundance of nectar, and of a quality which makes insects seek madly after it, The cueulli and the fleshy column are smooth, even slippery, the corolla yielding, so that insects in quest of this nectar find difficulty in re- taining a firm footing-. All the while the insect is clawing the disk and cuculli, never feeling stable, yet acquiring some of the much-coveted sweets. While insects are thus at work, their claws, or the hairs of the tarsi or the tibia, are caught in the \vedge-shaped slit of the corpusculum. If the insect is strong enough, it brings away with it the corpusculum and its two swollen masses, one from each adjoining anther, or it breaks off the ensnared leg in its endeavors to escape. It' the insect is too weak to pull out the pollinia or to sever its connection by breaking the retaining member, it must in consequence die. Such tragedies are not of infrequent occurrence. In case the insect has power to carry away the pollinia, its trouble and dangers are not over, for it will most likely visit another milkweed blossom, where the complementary contrivance awaits it. This slit between the anthers is wider at the bottom for a purpose, and that purpose is to capture the pollin- ium which the insect, has brought from another flower; so the insect, in slipping about again upon this second flower, finds itself fast when the pollinium has entered at the base of the slit. To facilitate this the more, these pollinia when first removed become, upon the dry- ing of the bands or retinacula, twisted inward. This twisting inward of the pollinia enables their entrance to the slit to be made the more readily. When the pollinia
112
ELEMENTARY STUDIES IN INSECT LIFE
have entered the slit, the insect pulls them up into the stigmatic chamber. They will go no farther, and the insect finds itself a prisoner again. If escape is made it is generally by breaking the retinaculum. The in- sect then carries away the corpusculum and part of the
FIG. 96. Pollen-masses attached to leg of bee. a, central body (cor- FIG. 95. Leg of insect pusculum); 6, band (or retinaculum)
with small chain of corpus- joining pollen-mass to central body;
cula. Photographed from c, pollen-mass (pollinium). Drawn
nature by W. C. Stevens. from nature.
retinaculum. This serves to catch other corpuscula rest- ing in their natural positions, so that we can frequently find insects that have continued their visits, bearing a whole chain of these corpuscula attached to a claw or some part of the leg. (Fig. 05.) Many insects are at- tracted bv the nectar. It is evident that only the strong
«/
favor the plant. The honey-bee is among the most frequent visitors, and no student can remain long among milkweeds in blossom without observing successful cross- pollination or being an eye-witness to a tragedy.
The Yucca Lily and the Pronuba Moth. — The fertiliza- tion of the yucca blossom by a small white moth sur- passes all other modes of cross-fertilization by insects, since the insect is not induced to do the work by tempt-
PLANTS AND INSKC'IS 113
ing nectar, but pollinates the plant apparently with as much intelligence as a human being would do it, Xot for any benefit the moth itself may derive therefrom, but that succulent seeds may be formed within the pod upon which its yonng may be nourished.
The yucca, or yucca lily as it is sometimes called, is a familiar plant. Its white flower may be character- ized briefly by the rather short, distinctly spreading stamens, with the more extended pistil. The anthers are so remote from the stigma that self-fertilization can take place only by the merest chance.
«. */
The Pronuba moth is a showy white lepidopteron about one-half inch long, and seems to have been con- structed especially for a purpose in the life of the yucca. The mouth of our common moths and butterflies con- sists of the two long maxilla- united to form a proboscis, used in reaching the deep-seated nectar of flowers such as the honeysuckle. On each side of the proboscis, near the base, is a mere protruding point, represent- ing what is left of the once well-developed maxillary palpi ; then there are two well-developed labial palpi curving up from beneath the head on each side of the proboscis, between which the proboscis is coiled up when not in use.
The female Pronuba moth, the yucca polleni/.er, lias all of these, but the little protruding point on each side of the proboscis is well developed into a four- jointed palpus. From its base there arises a highly specialized organ, which for want of a U-tter name we call the maxillary tentacle. These tentacles are coiled somewhat similar to the proboscis, but are readily distinguished —8
114
ELEMENTARY STUDIES IN INSECT LIFE
der head with maxillary tenta- cles coiled around it. Photo- graphed from nature. X 6.
from them by their large size, darker color, and spinous covering; also by their position, since the proboscis is situated between them.
The female Promiba moth rests quietly during the
clay, head down ward in the blos- som of the yucca. About sun- sct, or soon after dark, she may be seen running np to the top of one of the stamens, and col- lecting pollen from the anthers by extending the tentacles and proboscis ont over the stamens, FIG. 97. Head of Pronuba giving her a firmer hold upon
moth, showing pollen-mass un- -, , . . •,
the stamen and bringing the head close to the anthers. She now moves her head back and forth, using the maxillary palpi to scrape the pollen from the anthers toward the tentacles. The pollen gath- ered, she packs it in a little pellet under her head, using her front feet as well as the tenta- cles. Then she goes to a second stamen, collects more in the same way, and then to another, until she has collected a pollen- mass larger than her head. (Fig. 97.) She generally flies to another flower to rest awhile, head downward. After resting, ^ 9g Ovipositor of Pro.
in SOme Cases Ollly a few mill- nuba moth for insertion of egg . in deep ovary of yucca lily.
utes, in others a much longer (After
PLANTS AND INSECTS
115
time, she scurries around the base of tlie stamens, as- cends between two of tlie stamens until her head is slightly beyond the anthers (Fig. 99), inserts her ovi- positor (Fig. 98) into the ovary, there to place an egg.
FIG. 99. Female Pronuba moth ovipositing on ovary of yucca Illy. Photo- graphed by flashlight from life, in field, about 8:30 p. M.
She withdraws the ovipositor in about a minute. She retracts this interesting little tool by two or three jerky motions. She now quickly ascends the pistil and thrusts her uncoiled tentacles and proboscis into the stigmatic opening, rubbing them against the stigmatic surface. In doing this her head bobs up and down several times. She returns to the base of the flower, to ascend between
116
ELEMENTARY STUDIES IN INSECT LIFE
another pair of stamens and repeat, the operation of egg- laying. In this way she places five or six eggs in the ovaries of this flower. After depositing each egg s]ie ascends the pistil, and with the same motion, working
Fio. 100. Female Pronuba moth thrusting her tentacles and proboscis into the stigmatic opening, rubbing off pollen, thus bringing about fertilization of the lily. Photographed by flashlight from life, in the field, about 9:00 P. M.
her head vigorously (mostly np and down), places more pollen in the stigmatic tnhe. During all this time she is so intent upon the work that one can observe her closely with the aid of a lantern. The moths begin this work shortly after dark, and continue at work about an hour.
PLANTS AND INSECTS
117
Now, why does this female Pronuba moth do all this ( It has been shown that down in the stigmatic opening there is no nectar to attract her; she does not eat pollen. Then why does she perform this marvelous act of pollination? She does it to insure food for her young. For, though the eggs were laid in the ovary, unless the ovules were properly fertilized they would wither, would not develop; so the young caterpillars would perish. A> ii is, the hairy tentacles, surrounding and rubbing against the pollen-mass under her head, take oft' some of the grains of pollen, and these are left in the stigmatic chamber when she thrusts her proboscis and tentacles therein.
And what is I he sequence of this act? The pollen in due time fertilizes the ovules; these begin to develop, and at this stage may be likened to newly formed garden peas in the pod. Xo one needs to be told that these young peas are more tender, more succulent than the fully mature pea. -lust as these ovules are forming, the moth egg which is beside them hatches, and the little caterpillar finds awaiting him a breakfast of new peas. As the seeds develop, the larva grows; the two mature together. About the time the seed-pod is ready to burst open the larva bores its way out, descends the plant to the ground, burrows several inches below the surface, spins a silken cocoon intermixed with earth, there to spend the remainder of the summer, the fall and winter, awaiting the opening of the yucca flower the next sum- mer, then to emerge to repeat the story, — a series of acts as yet unaccounted for.
Has the question occurred to you, what benefit is the plant to derive if the insect eats all the seed?
118 ELEMENTARY STUDIES IN INSECT LIFE
Were the total consumption of seed the rule, it is evi- dent the plant would soon become extinct, and with it the Pronuba moth. Such is not the case; the elongate ovaries bear many ovules, more than the larvae enter- tained will in all probability consume, and so enough seeds are left unharmed to insure the continuation of the yucca lily seeds, which will in turn arise to make possible the further existence of the interesting little Pronuba moths.
Ol'K Kill ENDS AND FOES
119
CHAPTER VIII OUR FRIENDS AND FOES
OT every one, indeed, is aware of tlie fact that insects fill an important part in the economy of nature. We receive direct benefits as well as material in- juries from insects, and it is within the province of entomology to distin- guish the character of the insects.
As scavengers, as fertilizers of vegetables and fruits, or as food for other animals, they not only concern man, hut, philosophically considered, certain insects are seen to be essential to his very existence. From them we receive our sweetest of sweets, several inks and dyes, our finest of tapestries, a number of acids of chemical value, and laces and waxes of mercantile worth. That, we receive injuries, no one needs to be told.
In nature the term " friend " is a relative one. From the standpoint of the tree-grower, the caterpillar of the handmaid moth, which deprives the young trees of their foliage, is an enemy. Dame Xature, however, is as much interested in the welfare of the caterpillar as she is in the advancement of the tree or even of its owner. The caterpillar has as much right to the tree as has the fruit-grower. A review of biologic time, however, shows that it was not Nature's intention that one form of life should predominate at the expense <if another. ISTature endeavors to maintain an equilibrium between plant and
120
ELEMENTARY STUDIES IN INSECT LIFE
animal life. Man, the predominant type, brings to- gether large areas of the food plants of one insect, and here this insect finds conditions which favor its rapid multiplication. Its destructive possibilities become more apparent when directed against those forms of plant life from which man gains his sustenance ; and in order to subsist, man is forced to turn his attention toward this plant-eating insect. Man has made this condition possible not only by planting large areas of one field crop or of fruit trees, but also by removing the native forests, the homes of the birds, man's friends. Xot only has he destroyed the homes of the birds, but too frequently he has also ruthlessly taken their lives. In discussing our friends and foes, let us subdivide them from the standpoint of the parties interested, and so consider them friends and foes of the fruit- grower, the farmer, the housekeeper, and finally of man
himself.
OF THE FRUIT-GROWER.
The horticulturist is a student of biology, an observer of the workings of life. The life which the horti- culturist studies is represented by that invisible stream of life within twig and leaf. If you would see the results of his studies, look first at the wild crab and then at the Winesap, the Gano, the Jonathan. Has he not studied this life-current well i
A successful fruit-grower must also be able to de- termine what insects are injurious and what are bene- ficial. To do this, then, he must know their life history, and bv that is meant the time of year when the ee'2's
«/' ~o
are laid; where they arc laid; when they hatch; whether they hatch out as caterpillars or in a form
OUR K1MKNDS AM) FOKS
121
FIG. 101. Scale insect (Pulvinaria pruni) on plum twigs. Subsists on the sap, which it draws out through its slender beak. An insect injurious to horticulture. From a photo- graph.
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ELEMENTARY STUDIES IN INSECT LIFE
similar to the parent ; what they feed upon and the time when they mature ; how their food is procured,— whether !>y grasping and chewing with jaws, or by sucking through a beak. These things he can learn from books, but he can learn them far better, just as he has gained his best knowledge in horticulture, by the vigilant use of his eyes while following his chosen profession. If the insect, eats the leaves, as caterpillars do, the successful horticulturist knows that this insect can be reached by poisonous sprays thrown upon the leaves. If the insect procures its fond by inserting its beak into the leaf, the fruit-grower will readily understand that a poisonous spray will not kill this insect, since it does not eat the leaf spread with Paris green, but pushes its beak down through the poison into the leaf and with- draws its sustenance unharmed.
One of the earliest instances of successfully combat- ting an insect took place in Sweden. In the time of Linnaeus the Swedish ship-builders were seriously both- ered by a borer destroying the ship timbers in their yards. They applied to Linnaeus for assistance. This noted naturalist, after Diving the subject of the life history of the insect careful study, told the ship- builders that if they would submerge the timbers in the sea during the month of May they would have no further trouble from the pest. The naturalist had found that these borers were the larva1 or grubs of a beetle which lays eggs upon the wood only in the month of ~Mi\\. lie readily perceived that if this wood could be placed where the beetles could not find it during this month they would be compelled to deposit their eggs elsewhere. Then when the eggs hatched, the young
OUU FKH.M'S A.\D FOKS
\vuiilil perish for want of proper nourishment. Let us see if we can apply similar principles to the work in hand.
Let us take up the insect enemies as we meet them in the year, and discuss them chierly with a view to prevention rather than to combatting' them after they have made their appearance.
Tent Caterpillar.— -If the keen-eyed horticulturist will walk through his orchard during the winter months when the trees are bare, he will now and again perceive a twig- that has a peculiar swelling, and he will see that the swelling is caused by a band of small eggs carefully laid side by side and well covered over by a waxy substance. These are the eggs of the apple tent caterpillar,1 which are ready to hatch with the first days of spring. The almost microscopic caterpillars will go out, ready to feed upon the opening buds. Xow if the horticulturist will apply his pruning-knife and remove the twigs and cast them into the fire, lit' will have coped very successfully with one of his i enemies. If, on the contrary, however, he is spending his time in other pursuits at this winter season, there will appear early in the spring in his orchard great clusters of caterpillars well housed in large webs in the forks of his trees. They will go from this house
FIG. 102. Eggs of apple- tree tent caterpillar, sur- rounding an apple IWJK Drawn from nature, by Miss M. E. Wise.
1 Clisiocampa americana.
ELEMENTARY STUDIES IN IXSECT LIFE
to defoliate his tree and to lessen the fruit crop thereon. If lie desires to combat them at this time the labor is much increased: the whole fork must be cut out, or else the large web with its inhabitants must be brushed away. 1 5ut before this stage has been reached the horticul- turist has already suffered a loss in foliage destroyed,— a loss which he cannot repair. The trees, if neglected, are soon stripped of their foliage. The vital powers of his fruit trees, then, are so greatly taxed that they usually bear little or no fruit that season.
Canker Worm.1 — As the horticulturist is at work among his trees about the time the foliage begins to cast a
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,
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FIG. 103. Parents of the spring canker worm : a, female ; b, male (Paleacrita vernata). Drawn from nature, by Miss M. E. Wise.
shadow, he frequently notes small caterpillars dropping down by a thread from the disturbed branches of the trees. A few days later he sees the same trees nearly stripped of their leaves. If these caterpillars, swinging in the air by their silken threads, do not alarm him, he will soon be more emphatically impressed by the defoli- ated trees. If, however, he is familiar with the life his-
1 Paleacrita vernata is the scientific n;im<> lor spring canker worm. Another species, Anisopteryx pometaria, appears usually in the fall.
OUR FRIENDS AM) FOES
125
tory of this insect, lie will know that the female is a windless moth which comes out from her tdbernating-case early in the spring and ascends the tree to lay her eggs thereon. If he has been aware of the probable presence of this female in his orchard, he will have banded his trees with ropes of hay or paper or cotton. These hands will have been smeared with printer's ink, coal tar or pine tar, or some such adhesive substance, which would have arrested her in her ascent and have held her last until she perished. Or if he has not done this, the first caterpillar swinging from its thread will have been to him a signal for the advance of the spraying-pump.
The Codling Moth.1-- Almost every lover of fruit has seen a wormy apple, and the well-informed know that the cause of that hole in the apple is a little worm, the parent of which we call the codling moth. This apple worm is one of the most serious obstacles in the way of the profitable production of apples by the average fruit- grower. From one-fourth to one-half of the apple crop in the United States is mined annually by this insect. It may be well, then, to give this important pest grave attention. It is likely that it was introduced into the United States from Europe in packages of apples or pears, and was probably brought over about the middle of the 18th century. At the present ! ime it is considered a pest in every section where apple trees are bearing. It is chiefly distributed by means of the apple, in which it lives until it is full-fed. In barrels in which these apples are packed it finds a very suitable place
1 Carpocapsa pomonella.
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ELEMENTARY STUDIES IN INSECT LIFE
for its transformations. From the pupa-case it awakens to spread depredation wherever fate may have placed it,
The loss due to this apple pest reaches enormous sums. One year it was estimated that the loss in the State of Illinois clue to this apple worm amounted to $L\:5 75,000, or one-half of the average apple crop. An- other year the insect is said to have caused a loss of $2,000,000 to the apple crop of Nebraska.
The average annual crop of apples in New York
m^r •:-• -3,.m
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FIG. 104. Some codling moths — natural size. After photograph by M. V. Slingerland.
amounts to about 5,000,000 barrels: at $1.50 per barrel this would amount to $7,500,000. Although New York fruit-growers are fighting this insect, with modern methods, it is estimated that the wormy apples amount to about one-third of the total crop ; or in other words, New York apple-growers pay an annual tribute for the ravages of this pest of about $2,500,000 worth of apples. To this must bo added at least $500,000 worth of pears. This makes a total tax which is to be borne by the fruit-growers of New York amounting to $3,000,000.
This insect's food consists largely of apples, wild
OUR FRIENDS AND FOF.S
127
Laws, crab apples, and quinces. It also shows a decided taste for pears, and has been found upon peaches, apri- cots, and cherries.
Comparatively few frn it-growers, doubtless, are ac- quainted with the parent moth. The insect is about an inch in wing expanse, and has brown-colored front wings with lighter brown-colored hind wings. It might
FIG. 105. A pear and two apples. The petals have fallen. The calyx lobes are still widely spread. Just the right time to spray. After photograph by M. V. Slingerland.
be well here to enter somewhat into the life history of the codling moth, in order that the stages through which this insect passes may be more fully understood. The egg is laid upon the side of the apple, like a minute drop of milk adhering to the skin of the fruit. It has frequently been supposed that it is always laid upon the fruit itself; this is not the case, as investigations
128
ELEMENTARY STUDIES IN INSECT LIFE
have shown that the eggs have been laid upon the twigs as well as upon the apple. In a few clays, dependent 11 pun the character of the weather, the egg hatches, and I lie young worm seeks its first meal. It wanders about npon the surface of the apple until it finds some an- gular place like the blossom end, or where a leaf of the tree touches the surface of the apple. Generally the worm crowds in between two of the calyx lobes, and gels its first meal within the little cavity at the blossom end. Note the fact that in the majority of cases this little worm gets its first meal in the blossom end of the apple. And here it spends several days feeding around in the calyx cavity before it mines to the center of the apple. These first few days of the apple worm's life, which are usually spent in feeding in the blossom end of the apple, have proven to be the most vulnerable phase in the life of the insect, It is during this time that, it can be killed by the poisonous spray to be spoken of later.
You are all familiar with the appearance of the worm-hole in the apple and the bits of brown dust around the margins of the hole. When the caterpillar is ready to leave the fruit it pushes away this dust, and crawls out, leaving the open worm-hole; when one has a wormy apple in hand, it can be easily told by the absence or presence of these pellets of dust whether the worm is still within the apple or not. If the fruit has fallen to the ground, the caterpillar proceeds to crawl to some secure and suitable place in which to make preparations for becoming a moth. It seeks a suit- able place to spin its cocoon, in which to undergo its further transformations. Some go to trunks, large
OUR FRIENDS AND FOES
129
branches, or into the crotches of trees, to pnpate undrr the rough, loose bark. Others seek quarters in near-by fences or piles of rubbish.
If the worms are carried in the apples into the store- room, or packed with the fruit when it is picked, they spin their cocoons, after leaving the fruit, in the crev- ices and angles of the barrels, or in any secure portion
FIG. 106. A pear and two apples. The calyx lobes are closing up, especially on right-hand apple. Almost too late to spray effectively. After photograph by M. V. Slingerland.
of the store-room. The first brood generally attains the adult stage about the first of July. This brood coming out at this time is ready to lay eggs which will in turn hatch and attack the apples still remaining upon the tree. The insect is two-brooded in the United States. The worms of this second brood enter the fruit not so frequently at the blossom end. They generally enter on the side, making a spot which greatly disfigures the fruit.
A word about the habits of the parent moth. It is —9
130 ELEMENTARY STUDIES IX IXSECT LIFE
nocturnal in its habits. Unlike many other moths, the codling moth is not attracted to the light. This has been shown many times by experiments with lanterns. ^N'>r is it attracted to baits of any kind. How then can this insect be overcome? Since the codling moth cannot be taken at lights or by traps, the only possible means of destroying it in the adult stage is by keeping the fruit cellars screened in the early spring, so that the emerging moths may be prevented from escaping until they are captured within the cellar and killed. Xo satisfactory way has presented itself for the destruction of the eggs. .V few of the pupa-cases may be found and destroyed, but it appears that the chief and surest remedy lies in attacking the young apple worms.
Many experiments have shown that spraying is the most effective means of ridding the orchards of the pest.
First of all and by all means secure a first-class spray- ing-pump. Time and money used in working with a home-made device or cheap spraying-pump is worse than wasted. Get the best spraying-pump the market affords, and your work will be more than repaid. Having se- cured a pump, use a mixture of Paris green in accord- ance with the formula given on page 303.
The time to sprav is a few davs after the blossoms
I » «
have fallen and before the calyx leaves have begun to close up. (Fig. 105.) The object of the spray is not to water the leaves nor the sides of the apple. The idea in the mind of the sprayer is to fill the little cup at the rose end of the young apple with this fluid. This can be done only while the calyx leaves are yet open. From this you will see that different varieties of apples will require to be sprayed at different times. If
OUR FRIEXDS AM) FOES
131
you will review in your mind what has been said, von will see that when these cups ar the blossom end have been filled with this poisonous fluid the water will evaporate and leave the particles of poison therein to be eaten by the young' caterpillar at his first meal, and. consequently, at his last meal. This is the secret of combatting the codling1 moth successfully. If you rid your orchard of the first brood it will be evident that there will be no second brood. Having1 neglected this, however, the second brood can onlv be destroyed bv
• t' «.-
shaking the tree and gathering and destroying the wormy apples.
The Honey-Bee.- -The above are some of the more in- jurious insects met. by the horticulturist. Xo\v let us note his friends of this class. Xot the least among these is the honey-bee, which visits his orchard-, his vine- yards, his strawberries, blackberrie-. and raspberries, and brings about greater results than is generally cred- ited. It was formerly supposed that plants fertilized themselves, but it has been more recently shown that many plants are so constructed as to prevent self-fertili- zation; or, in other words, plant life, like animal life, will " run out,1' as we term it, by in-and-in breeding. And nature has so constructed the plant itself that it is impossible in some cases for the pollen of its own anthers to fall upon the stigma of its own ovary. In other cases the stigma is sterile to the pollen from its own anthers but t'< rtile to pollen brought from other flowers of the same species. It is the intention of nature that the insect shall bring from another flower of the same kind, pollen which shall fall upon the stigma and
132
ELEMENTARY STUDIES IN INSECT LIFE
fertilize the ovules, thus keeping the breed strong and healthy. (See pages 95, 96.)
Fruit-growers are known to object to the presence of bees in their locality, because they think the bees destroy grapes, peaches and other fruits by breaking the skin and sucking the juices. The Department of Agriculture at Washington has given this matter a thorough test by placing hives of bees in a large closed house ; here these bees had no opportunity to secure food of any kind. In this house where those starving bees were kept there were hung all varieties of fruits, such as grapes, peaches, apples, plums, nectarines, and many other classes of fruits. Observers were placed beside each kind of fruit to notice the action of the bees thereon. It was universally noted that not a bee was observed endeavor- ing to cut into any variety of fruit, regardless of the delicacy of the skin ; but when the skin was broken by decay or bruise, or any similar cause, the bees naturally inserted their tongues and lapped up the escaping juices.
Wasps. — The horticulturist has many friends within this one order to which the bees belong. There is a great variety of that class of wasps which are known as " mud-daubers " and the like, whose silent work in killing caterpillars and carrying them away as provi- sion for their young is of inestimable value to the horticulturist.
Parasitic Insects. — Then there are those of the bee family which we speak of as parasitic Hymenoptera. These insects lay their eggs upon the backs of cater- pillars ; the young from these eggs attack the cater-
OUK FRIENDS A.N'I) FOES 133
pillars and kill them. The caterpillars become a " peri- patetic banqueting-hall for unbidden guests." Then there are others of this same group which lay eggs among the eggs of injurious insects such as the codling moth, and as their eggs hatch the young larva? sustain themselves upon the eggs of these injurious forms. Of these Hymenoptera there are no less than four that prey upon the codling moth.
The insect friends of the horticulturist are classed under three heads : as pollenizers, as parasites upon in- jurious forms, and as predaceous insects preying upon injurious forms. The bee was an example of the first, the ichneumon fly of the second, and chief among the third might be mentioned the ladybirds or ladybugs, about which there is the rhyme,
"Ladybird, ladybird, fly away home : Your house is on fire, your children will roam."
Predaceous Insects.— - These bright red beetles with black spots on their backs are preeminently the friends of the horticulturist. The little immature forms known as grubs or larva? spend their time in eating up plant-lice, scale insects, and many other injurious forms. The adult beetle is no less active. The
most remarkable case on rec- ^ 107- "L^yw.i" and larva,
Coccinella abdominalis.
ord of the beneficial results
derived from a single insect is that of a member of this group of ladybirds. A few years ago the citrus or orange industries of California were al-
134 ELEMENTARY STUDIES IN INSECT LIFE
most destroyed. It had come to be considered that the culture of oranges would have to be suspended, owing to the highly destructive work of a certain white scale known as the fluted scale. It was found that the native home of this scale was in Aus- tralia. It was observed that in Australia a certain one of these ladybirds subsisted exclusively upon this white scale. A force of men captured a large number of the ladybirds, brought them to California, and distributed them among the orange groves. The result was that in a few years the scale had almost en- tirely disappeared, and to-day it can be found only in very limited numbers in any place in the State. This condition of affairs is due wholly to the active and per- sistent work of this little ladybird. Xot only has this same insect made orange industries profitable in Cali- fornia, but it has been introduced into Portugal, where it is doing equally good work for the orange groves of that country.
Then there are those beetles which we commonly call ground-beetles (p. 277), always to be found on the ground, some of them of good size and some of them of smaller sizes. They spend much of their time digging about for the eggs of injurious insects, and many of them subsist almost exclusively upon the grubs of injurious forms. Frequently one of these allies meets its death under the foot of some horticulturist who erroneously believes it to be an enemy.
OF THE FAEMER.
Farm products are not exempt from the presence of insects both beneficial and injurious. Should the
on; ]• KM KM is AND KOKS
135
farmer devote his attention to the production of wheat, just before he is ready to garner it he finds that cer- tain insects harvest a quota proportionate to their
FIG. 108. Ear of corn, showing holes made in kernels by larvae of AngoumoiH grain moth, Gelechia oerealella. From photograph.
numbers. Chief among these is the chinch-bug, iti small dark-colored insect with light-colored wings.
The Chinch-Bug.— - Kach female chinch-bug lays about 500 eggs promiscuously on the ground early in the spring. These soon hatch as little red, spider-like forms, and seek their nourishment from surrounding plants. They do not eat the stalk, but insert the beak and withdraw the life-juices of the plant, causing il to dry up prematurely. In about six weeks these young red insects arc mature, and ready to reproduce their kind. It is this second brood that sometimes make- sad havoc in the grain-fields of the farmer. The (pics tion then is, What means of defense are at the disposal of the farmer? lie has not manv insect allies to aid
»
him in the reduction of this insect. There are certain contagious diseases which break out under certain cli- matic conditions. These conditions are obtained when the weather continues warm and moist. When these conditions prevail and the chinch-bugs are numerous, great numbers of them will die in a short -pace of time from contagious diseases. When, however, the weather
136
ELEMENTARY STUDIES IN INSECT LIFE
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OUK FRIENDS AND FOES
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is hot and dry, conditions naturally favorable to the increase of bugs, the farmer must rely upon artificial barriers. Ridges covered with tar or similar adhesive substances placed through the field prevent, the insects' advance into new territory, since during their most destructive period they are wingless and must proceed by traveling along the ground. Post-holes placed at in- tervals along the side of this ridge will trap great num- bers of these invading insects. (Fig. 109.) Clean, careful farming, gathering rubbish and burning the same in the fall will remove opportunities for the adult insects to hibernate in security. When this is done many will not live to reproduce their kind the follow- ing season.
Grasshoppers.- -These frequently cause great destruc- tion to cultivated crops. The most noted among the destructive forms in this country is the Rocky Mountain locust. This insect eludes all effective means of de- fense, since it is migratory, and appears in hordes with- out previous warning.
There are, however, many native forms which live and die near the place of birth. These the agriculturist can readily dispose of. The life history of one of these has already been studied. It has been observed that they spend the winter in the egg stage in pods, about one hundred in number, about an inch below the surface of the soil. It is evident that if these eggs are destroyed, no grasshoppers will appear to injure vegetation. This should then be the first point of attack. In the fall the female lays about 100 eggs, in a hole made by herself and extending an inch or so beneath the surface of the
138 KLEMKXTARY STTDIES IX IXSECT LIFE
ground. As the female grasshopper lays the eggs, slie places an impervious glutinous coating around them. This glutinous material hinds the eggs together and surrounds them so as to form a water-proof pod molded to the shape of the hole which the insect has made. If the ground is disturbed in the spring these egg-pods will be broken up, exposed to the sun and rain, to sud- den changes in the weather, to birds, and to other insects. All of these conditions are highly injurious to the life of the embryonic grasshopper, and few of these insects
FIG. 110. A beneficial insect. Praying mantis (Mantis religiosa) eating live grasshopper which it has captured with its strong, spined fore legs— natural size. Photographed from life by M. V. Slingerland.
will hatch on ground thus treated. If the ground is not disturbed the eggs protected from the winter snows and spring rains by this water-proof coating will hatch; and as small nymphs the young insects will find their way to the surface to begin their work of devastation.
(•I i; i-'lMEM)S AND FOES
139
How can we disturb this soil in which the females have placed their eggs? If the ground is to be plowed in the spring this will suffice, but in the case of meadow lands and pastures this cannot be dune. In the case of alfalfa, a meadow crop, it has been found that if this
FIG. 111. Beneficial mite. Red mite (Trombtdium locust arum), an fstrrnal parasite on membrane of wing of grasshopper, impairing powers of flight. Greatly enlarged.
crop be harrowed in the early spring with a disk har- row, the process greatly increases the growth of the plant, in both root and stalk. This results in a much larger yield of forage. This plant, by reason of its early spring growth, furnishes nourishment for I he emerging grasshoppers at a time when, if they had to hop far for succulent food, many of them would prrNi. So, fields which have grown this alfalfa crop year after
140
ELEMENTARY STUDIES IN INSECT LIFE
year on undisturbed soil are favorably placed for the increase of these native grasshoppers. There is in the undisturbed alfalfa meadow an opportunity for the quiet hibernation of the egg and the proper nourish- ment for the young insect. Life under such conditions is free from many of the contingencies which arise in the struggle for existence. Here these insects will be found in undue numbers until they have by con- tinuous defoliation destroyed their means of support, the alfalfa ; or until the farmer has interfered and removed them.
FIG. 112. Plan for hopperdozer.
It may not be possible to destroy all eggs by harrow- ing and plowing. To insure the destruction of such grasshoppers as may hatch, a machine called the " hop- perdozer " is used. This consists of two shallow pans about four feet long, two feet wide and eight inches deep, placed on wooden runners corresponding in height to the crop. At the back of these pans there
OUE FKIENDS AND FOES
should be placed, upright, a sheet-iron or canvas back. This back should be about three feet high. Its purpose is to prevent the insects flying over the pans. When the machine is ready for use, place two buckets of water and half a gallon of coal oil in each pan, hitch one horse to each of the outside runners of the hopper- dozer, and then drive back and forth across the field where the grasshoppers are either entering or are at work. As fast as the insects fill the pans, remove, and replenish with oil and water. This cheap and effective mixture of coal oil and water proves deadly to insect life. Where grasshoppers are troublesome, if the farmer will either plow or harrow his land in the early spring, and then in the summer will kill by means of the hopperdozer those that he did not destroy in the egg stage, he will practically destroy all the insects of this kind upon his farm.
The Army Worm. — There is an insect which occa- sionally appears in great numbers in the caterpillar stage. When in quest of food these larvte are wont to move in one general direction, eating all vegetation as they go. From these habits this insect frequently gets the name of the " army worm." 1 These insects occur every year, but not always in numbers sufficient to at- tract general attention. Sometimes, however, the num- ber of eggs deposited early in the season becomes very great, and the larvae hatched therefrom become so numerous that they are forced to travel in order to obtain food. Their traveling, rolling and piling one over another is not instinctive, but is simply a condition brought about by reason of their great numbers. When
sp.
142 ELEMENTARY STUDIES IN INSECT LIFE
the brood is few in ninnlior the larva finds, without much moving- about, sufficient nourishment to satisfy it. When the brood is large, as is sometimes the case, the caterpillars are forced to travel in order to satisfy their natural cravings for food.
These insects are two-brooded. The second or mid- summer brood is the one which furnishes the largest army of worms. Some of this midsummer brood emerge before winter to lay eggs, and others pass the winter in the pupal stage. It is probable that the ma- jority of these insects spend the winter in the larval or pupal state. If the ground is stirred by plowing or harrowing in the early spring, it is evident that the majority of the hibernating larva? and pupa' will be destroyed. Mechanical means, such as the cutting down of the crop on the edge of the field where the caterpillars are entering, and destroying this crop by fire, are effective, since the larva1 are burned with the crop. The
FIG. 113. Thepo- .
tato beetle (Dory- march oi this enemy can sometimes be
phora 10-lineata). (.}^}^] j)y plmving a furi'OW aCl'OSS its
front and dragging a log back and forth through the furrow, crushing the insects as they crawl into the furrow.
The Potato Beetle. — An insect which has been of great importance in connection with potato culture is the well-known potato beetle,1 ten-line beetle, or Colorado beetle. This insect passes the winter in the adult or pupal stage, and comes forth in the early spring to
^Doryphora 10-lineata
OUR FRIENDS AND FOKS
143
attack plants such as the potato as soon as these plants appear above-ground. Upon these they lay egg's which bring forth reddish, sing-like larv;r. This brood of larvne is the one which frequently defoliates the first crop of potatoes. Before the application of arsenites was fully understood, the potato beetle was an enemy of considerable importance. In those days the only means of ridding the potato patch was by hand-picking the eggs and insects. With a more complete knowledge of insecticides, however, we find little or no difficulty in treating the potato plants by spraying with Paris green one pound, freshly slaked lime one pound, water 100 gallons.
Squash-Bug.— -In garden crops the squash-bug and the cabbage worm are frequently injurious. The squash-bug1 attacks and causes considerable injury to the vines of the cucumber. This dull, grayish-brown insect belongs to the order Hemiptera, suborder lleteroptera, and therefore has sucking mouth-parts. The punc- ture made b the beak of this
insect when feeding seems to be FIO.IU. squash-bug
tristis). Drawn from nature, by
peculiarly poisonous, especially MISS M. E. wise. x2. to young vines. The insect spends the winter as an adult, and in the spring lays its golden-brown eggs upon the vines of the squash or cucumber family. These insects. as has been previously said, secure nourishment from within the plant, and therefore cannot be poisoned by ar-
Mstis.
144 ELEMENTARY STUDIES IN INSECT LIFE
senites. They can, however, be reached by what we speak of as contact poisons, the best of which is kerosene emul- sion. (For directions for making, see page 305.) This spray is a contact poison, since it kills the insect by com- ing in contact with its body, and not by entering the ali- mentary canal as is the case with arsenical poisons. Since these insects spend the winter in the adult stage in rubbish left about the garden plots or fields where vines of this family are cultivated, all such refuse allowed to remain favors their hibernation. In the fall, then, all vines and rubbish about garden plots should be raked up and burned, and in so doing many of the insects will doubtless be destroyed at the same time.
The Cabbage-Worm.1- -Farmers who are engaged in the production of cabbage for market, as well as those
Fia. 115. Cabbage butterfly (Picris rapce), parent of the cabbage-worm. Drawn from nature, by Miss M. E. Wise.
who raise only for home consumption, find considerable difficulty with the small greenish worm known as the cabbage-worm. The parents of this cabbage-worm were brought from Europe. They are about one and one-half inches in wing expanse, white or creamy white in color. The male has a single black spot in the fore
rapce.
OUR FRIENDS AND FOES
wing and the female two black spots in the fore wing. The points of the fore wings are also black. The under side of the wing is usually darker. These butterflies are to be seen in the early spring. They spend the winter in the pupal stage. They lay their eggs gener- ally upon sonic one of the plants that belong to the mustard family. These eggs hatch and the insects come to maturity in time to lay their eggs upon the early cabbage plants. Their presence is soon told by the ugly holes which appear in the outer leaves of the growing cabbage plant. Tin- caterpillars themselves show their protective characteristics in a marked degree, in that when feeding upon the cabbage leaves they re- semble the leaf so nearly in color and lie so closely to the plant tis-ue that they are easily overlooked. They can he destroyed, however, by the arsenical spray de- scribed on page 303. This is an effective remedy, and can be applied in the spring without fear of the poison remaining there to endanger the lives of persons who will later eat the cabbage, if applied before the cabbage-head
has formed.
Some Beneficial Insects.- -These are some of the prin- cipal insect enemies of the farmer. lie, like the fruit- grower, has friends among the insects, and these friends are of the same general character as those of the fruit- grower, viz., destroyers of noxious insects, by preying upon them, by being parasitic upon such injurious forms, and as pollenizers of the various crops. In addi- tion, certain other insects are beneficial in that they eat and therefore destroy certain noxious plants. An illus- tration of beneficial results derived from the predaccous —10
146
ELEMENTARY STUDIES IN INSECT LIFE
and parasitic insects may be taken from the fact that the army worm rarely appears in considerable numbers two seasons in succession, showing that these enemies severely check its increase. There are a number of flies somewhat similar in appearance to our common
FIG. 116. Different stages in transformation of parasitic fly (Sarcophaga sp.) : J, 2, 3, 4, white maggot in active stage ; 5, maggot beginning to pupate — dirty white in color, pupa-case light brown ; C, 7, fully developed pupa-case of two species. X 5.
house-fly. These flies are parasitic upon grasshoppers, and aid in keeping the grasshoppers in check. Some of these flies are illustrated in Figures 117 and 171. In regard to pollination of crops, reference has already been made to the fact that the honey-bee materially in- creases the yield of the alfalfa plant. (See page 107.) It is known that the bumblebee is very influential in bringing about the proper fertilization of the common red-clover blossom. However, injurious insects, such as the grasshopper, may not be looked upon as wholly in- jurious, since they frequently furnish food for the farmer's poultry. High-class farm culture tends to re- duce the numbers of injurious forms, and at the same
OUR FRIENDS AND FOES
147
FIG. 117. A fly, parasitic on grasshoppers. Enlarged.
time gives better crop yields. The work of destructive insects is not a total loss, since the part of the crop left will bring1 a price somewhat higher than if the whole crop had been placed upon the market. This is in the case of a general devastation by insects. From this stand- point neither the individual who lost his crop nor the State that lost its crop would be benefittedj but the individ- ual or State that harvested a part or all of the crop would be benefitted by the rise in price caused by its scarcity, this scarcity being due to the work of injurious insects.
OF THE HOUSEKEEPER.
The House-Fly. — Among insects, probably the one causing most general annoyance to the housekeeper is the house-fly. There are several species which are given this name, but the one most abundant is that known to science as Musca domestica. It is the ordinary grayish fly, with mouth-parts separate at the tip for sucking up liquid substances. It is not within the power of this specie? to pierce the cuticle. There is, however, an opinion prevalent that it can bite. This is not due to any of its actions, but to the resemblance of another fly, sometimes found in the house, a fly known as the stable-fly.1 This stable-fly is probably next in point of
^Stomoxys calcitrans.
148 ELEMENTARY STUDIES IN INSECT LIFE
abundance to the house-fly in most portions of the United States. The greatest structural difference be- tween the two is that the stable-fly has mouth-parts adapted for piercing the skin. The house-fly has no piercing organs in its proboscis.
The common house-fly breeds in fresh horse-manure, from which during the warm weather the generations emerge in quick succession. It is well, then, to prevent the prevalence and avoid the annoyances arising from the presence of this insect by seeing that all stables in the vicinity are kept perfectly clean, and the sweep- ings therefrom promptly removed or well covered with lime. As is well known, these insects can be practically excluded from the home by means of wire mosquito netting over the doors and windows.
The house-fly has a number of natural enemies, some being hymenopterous parasites, others being predatory beetles. The enemy which most effectually reduces the house-fly, however, is a fungous disease character- ized by the whitish swelled abdomen of the dead insect. This disease does not generally become epidemic until late in the season.
The Buffalo Moth.— - In some parts of our country the buffalo moth : or carpet beetle creates considerable dam- age among woolen goods. Like many of I lie common names given insects, the term " buffalo moth '" is mis- leading. This buffalo moth is not a moth, but belongs to the Coleoptera. In the summer and fall these insects are the most active, but in well-heated houses they may work throughout the year. The adult insect is a broad oval
lAnthrenus sj>.
OUR FKIEXDS AXD FOES
149
beetle ( Fig. 110), three-sixteenths of an inch long, with a brick-red invgulur stripe down the middle of the body. The wing-covers are black, but covered with minute whitish scales which give them a marbled black ap- pearance. The beetle itself is a day liver, and feeds
FIG. 118. Buffalo moth larva. FIG. lin. B-iffalo moth beetle (Ar>-
This is the stage in which the in- threnus scrophulariae). Drawn from
sects cut carpets, woolen goods, nature, by Miss M. E. Wise,
etc. Drawn from nature, by Miss M. E. Wise.
upon flowers such as the golden rod. The insect itself is not troublesome to the housekeeper. It enters her house to lay eggs in crevices or in the vicinity of woolen goods. TlicM1 eirgs hatch as reddish brown, hairy, oblong forms, which apparently have no head or feet. (Fig. 118.) The feet and head, however, are fairly well concealed beneath the bristly covering. The larva- have mouth-parts well developed for chewing. It is in this larval stage that the cutting of carpets and other woolens takes place. This in-ect is one of the most troublesome household pests to be found in the United States. Whenever a house1 becomes badly in- fested it frequently is necessary to abandon the use of
150
ELEMENTARY STUDIES IN INSECT LIFE
carpets for a time and use rugs in their stead. These rugs will require frequent exposure to the sun. Where the insects are quite general the carpets should be taken up, thoroughly beaten, and carried out of doors, sprayed with benzine, and allowed to air for several hours. The benzine is a very volatile substance and highly in- flammable, so that due care should be taken to keep away from lighted substances while this work is being carried on. The rooms themselves should be thor- oughly swept and dusted, and the floors should be washed with hot water.
Tne Clothes Moth. — A destructive insect among furs and wroolen fabrics is the well-known little clothes moth.1 Fur and woolen garments are its favorites. In its at- tacks upon these, possibly it has become the most gen- erally known household pest. It does not confine its attacks to the home alone, but is likewise to be found in the dry -goods store. The moth is a little buff-colored lepidopteron, being about three-quarters of an inch in wing expanse. These moths in themselves are harmless. Like the buffalo moth, however, the larva or caterpillar is the one which commits the depredation. In the North there is but one annual generation, the adults appear- ing from June to August ; in the South we find there are twro or even more broods annually.
K
The larva is a dull-white caterpillar, and is never seen away from its movable case. (Fig. 120.) The construction of this case is its first task. If it, desires to change its position it thrusts out its head and thorax, and by means of its thoracic leg drags itself to the de-
1 Tinea pellionella.
OUR FRIENDS AND FOES
151
sired location. As the larva grows it finds it necessary to enlarge its case both in length and circumference. The wav it does this is rather interesting. Without
<u
bursting its case the larva makes a slit half-way down one side, and inserts a triangular gore of new material.
FIG. 120. Larvre of clothes moth feeding on felt. Photographed from life.
A similar insertion is made on the opposite side. The larva revolves itself without leaving the case, and makes corresponding slits and additions in the other half. It lengthens its case by adding to either end. In appearances the case looks like a matted mass of wool. If the interior be examined it will be found to be lined with soft white silk. If the larva is trans- ferred from time to time to fabrics of different colors, the cases .may be made to assume as varied a pattern as one desires. The varied colors will illustrate the peculiar methods of enlarging just described. The fully developed larva about to pupate attaches itself by silken threads to the garment upon which it has been feeding.
t>>
152 ELEMENTARY STUDIES IN INSECT LIFE
or to some object near by. It emerges as a moth about three weeks later. The moth flies in an irregular man- ner, but can run well over clothing wThen disturbed. The moth prefers darkness, and successfully conceals itself in dark folds of the garments or in crevices when disturbed.
Unfortunately, there is no good method of prevent- ing the damage done by these insects. Constant vigi- lance and frequent inspection are demanded whenever these insects become troublesome. The various repel- lents, such as camphor, moth-balls, tobacco, etc., are of little value if the garments are alreadv stocked with
o v
eggs, since these will hatch and mature regardless of the odor. The moths, however, are repelled from de- positing their eggs while these odors are strong. But if the moths are inclosed with garments protected by these repellents they will naturally lay their eggs and the destructive work of the larva will soon begin. The remedy which seems to be the most satisfactory, though attended by a good deal of trouble, is to sun and brush thoroughly all winter clothing, then place away in large boxes such as tailors use, and seal the boxes up by gumming a strip of wrapping-paper around the edges so that the boxes will be completely sealed up and leave no cracks. In this way the insect is denied entrance, and therefore no damage is done.
The Cockroach. - - Then there is the wary and trouble- some cockroach. So well known are they as to make a description unnecessary. Various poisons, such as phosphorus paste spread on cardboard and placed in the runways of the roaches, have been used with fair
on; KiMKxns AND FOES
153
success. Wherever the apartments infested are small
and can be tightly closed, these insects can be killed by
fumigation with carbon bisulphide,
a volatile and highly inflammable
substance. Therefore great care
must be taken to keep lighted
matches away from its gases. FlG- 121- Esg-P°d of
cockroach.
Place the substance upon pans in
the room, and then close the room and the substance will evaporate. If used in sufficient quantities this carbon bisulphide will kill the insects. It is very necessary, however, that the mom be made tight, in order that none of the gas may escape. It requires a strong gas to kill the insects.
House Ants. — Another form which proves troublesome in the cupboard and on the pastry shelves is the ant, and of these there are a number of species which fre- quently prove troublesome to the housekeeper. Carbon bisulphide poured upon the hole from which they emerge, —this is the entrance to their nesting-place, — will effect- ually free the house of them. If, however, their nests cannot be found, it becomes necessary to destroy them whenever they are found in the house. This can be done by placing large sponges in situations where the insects are most numerous; these sponges, being sat- urated with sweetened water, will collect the ants in great numbers. The sponges <-i\\\ be placed in hot water several times a day, thus killing the ants.
154
ELEMENTARY STUDIES IN INSECT LIFE
OF MAN IN GENERAL.
While the foregoing insects indirectly affect man himself, there are some which directly have to do with his comfort or discomfort. There are very few habita- ble regions where man is not personally subject to more or less annoyance from insects. In this part of the world we at once think of mosquitoes.
The Mosquito.— - The eggs of the mosquito are depos-
FIG. 122. Mosquito ( Culex pungens) In process of development : Egg mass above ; two eggs, much enlarged, just below ; young larvte, enlarged, below. Three of these are represented as at the surface of the water breathing through the caudal tube or trachea. (After Howard.)
ited in small boat-shaped masses, and the young hatch- ing from these escape into the water. We frequently find the half-empty rain-barrel well supplied with these larvae, commonly called " wigglers." These move about
OUK FEIENDS AND FOES
155
by a jerky motion, ascending' at times to the surface for a supply of air. This they take in through a slen- der tube at the caudal end of the body. The pupa,' are active, and can readily be distinguished from the larva?. The head of the larva or wiggler is not natu- rally large. The pupal head has the feet and developing
Fio. 123. Full-grown mosquito larva on left. Pupa on right. Much enlarged. (After Howard.)
wings folded around it, so that the pupa is quite easily distinguished from the larva by the size of its head. This distinction can be made as the insects are observed in the water in the basin in which they have been col-
156 ELEMENTARY STUDIES IN INSECT LIFE
lected. The pupa takes air through a spiracle near the head. When the insect is ready to emerge, the pupa rests at the surface of the water, the dorsal portion of t he- body slightly out of the water. The pupal case splits, and the mosquito draws out first the fore legs, which are placed on the water to serve as a support while the rest of the body is withdrawn. The wings expand quickly,
FIG. 124. Mosquito (Culex pungens), female. (After Howard )
and the insect flies away. The pupal case serves as a raft upon which the insect floats momentarily while the wings are drying. Should there be a brisk wind at this moment, the insect will be blown from its raft and drowned. This is not an infrequent calamity in the life history of the mosquito.
In the matter of remedies we are all familiar with the use of mosquito netting over doors and windows of dwellings. The best means of dealing with the mos- quito are preventive. Rain-barrels should be kept se- curely covered. A rain-barrel allowed to stand open with sufficient dregs will furnish a breeding-place for enough mosquitoes to torment a household. There are three principal remedies : standing pools can be drained ; ponds can be well stocked with fish ; or kero-
OUR FRIENDS AND FOES
157
sene, about one ounce to fifteen square feet of water, can be poured over pools of water which cannot be read- ily drained. If the ponds are drained the breeding- places are ruined. If fish are introduced they feed upon the larva1 and pupa\ If the surface of the water is given a coating of kerosene, the pupsr, as they come to
FIG. 125. Mosquito (Culex pungens), male. (After Howard.)
the surface to emerge, will be killed, and the female depositing her eggs on the surface will come in contact with the kerosene. This will destroy her before she has had an opportunity to deposit her eggs. These are three effective remedies. The one best suited to the occasion can be chosen.
Mosquitoes are looked upon as annoying only in so far as they directly disturb man. There are good reasons for believing that mosquitoes may act as disseminators of disease. It has been partly proven that mosquitoes
158
ELEMENTARY STUDIES IN INSECT LIFE
breeding and living in the swamps introduce into the human body with the insertion of their beaks that which brings on malarial fever in the person bitten. Insects as carriers of disease is a subject only coming to be understood and studied. Bites of the horse-fly l and the stable-fly 2 have developed into grievous pustules, show- ing germs of anthrax, a malignant contagious disease, transmissible from cattle to man and from man to cattle. Insects which frequent or breed in decaying animal or vegetable matter should certainly be kept from contact with man and his food.
This phase of insect injury is to be classed as of the greatest importance, and is a subject which deserves the notice and attention of every one who cares for cleanliness and health.
Beneficial Insects. - - Insects are not wholly injurious when viewed from the standpoint of man. As scaven- gers they render humanity invaluable service. The services of certain insects in doing away with and rendering harmless dead matter of both plant and ani- mal origin are inestimable. Linnivus, the great nat- uralist, stated that the offspring of three blow-flies would destroy the carcass of a horse as quickly as would a lion. This statement may be somewhat exaggerated, yet it serves to illustrate the good offices of insects. Certainly the offspring of the blow-fly would leave the carcass of the horse in a much less offensive condition than would the lion. Large groups of insects play an important part in cleaning up and removing decaying matter which, if allowed to remain, would certainly
lTabanus. "Stomoxys.
FRIENDS AND FOES
159
prove detrimental to health as well as highly offensive to the senses.
Insects are further valuable to man in that they furnish food. Chief among the insect foods used by man may be cited honey from the honey-bee, — a nota- ble article of food upon which is based a great and world-wide industry. Manv insects furnish food for
«/ *J
poultry, fish, and song-birds ; being therefore indirectly beneficial to man.
In the matter of clothing it- is well to know that our silk is derived win illy from insects. The delicate silken fiber of which the cocoons of the silk-worm are made, is the crude material from which the silk of commerce is manufactured.
The cochineal dyes, formerly so greatly used, are in- sect products. Shellac and Chinese white wax are like- wise products of insects.
These are some of the principal relations which exist between man and insects. Man is the dominant type, and his appearance directly or remotely changes the whole train of natural laws. We can readily see the sequence in the statement of Wallace, that the more old maids the more abundant the clover-seed crop, for the maids protect the cats which kill the mice which rid the nests of bumblebees which fertilize the clover-seeds.
In our study of injurious and beneficial forms it be- comes essential that we acquaint ourselves with the life histories of the insects which affect us either beneficiallv
»/
or otherwise, in order that if a check need lie made, we may be aware of the most vulnerable point of the inju- rious insect. We should likewise become acquainted
160 ELEMENTARY STUDIES IN INSECT LIFE
with the structure and feeding habits of the insect. If the injurious insect has mandibles and masticates its food, it can then be reached by poisoned baits, or by poisonous sprays thrown upon its food plants. If the injurious form procures its food through a sucking- tube, we then must use contact poisons, — those which destroy the insect by coining in contact with its body. We should likewise become acquainted with our friends in the insect tribe, in order that we may at all times favor those which favor us. This whole subject is in- cluded under the head of economic entomology — a phase of the study inviting to young students.
In this study there should be at all times an attempt to reach the proper point of view ; that is, the causes and effects. For instance, the short-sighted fruit- grower is sometimes prone to overestimate the evils at- tending his vocation; some are wont to recall the "good old times " when none of these pests existed. These fruit-growers forget that in those times there were no orchards, and that the apple industry was represented by a few seedling trees growing about the pioneers' log cabins. The farmer likewise sometimes becomes discon- solate by reason of the unexpected attacks of an invading insect horde. There is behind these attacks some cause. The farmer has probably continued to raise throughout a series of years, upon the same ground, the food plant of the invading insect. Had there been frequent rota- tion of crops this state of affairs would have been avoided. In reulitv, then, the agriculturist himself
t^ / O
is at fault for the undue prevalence of the injuring forms. If flies become exceedingly troublesome around
OUR FRIENDS AND FOES
161
the house, it will be advisable to inquire into the condi- tions of the stables in the vicinity. Properly kept stables will greatly reduce the number of flies.
It will be found that gregarious insects do not appear in such great numbers year after year: there must be some cause for this. It will be an interesting problem to be solved.
The enemies of insects increase as well as the com- petitors. Parasites, attracted by innumerable insects upon which they prey, increase so rapidly as to devour their own means of support. They in turn succumb and the defeated host rallies ; so the alternate warfare goes on forever. And in the activities of these beings which we are wont to consider beneath us, there is much for profitable observation and careful study.
102 ELEMENTARY STUDIES IN INSECT LIFE
CHAPTER IX THE WEALTH OF INSECT LIFE — ORDERS
INSECTS, numerically considered, comprise four- fifths of the animal life of the globe. There are now about 250,000 species to which names have been given. This number, it is estimated, is about one-tenth of the existing forms. If we look at a number of these we find great differences in appearance and structure. If an examination be made of those which at first glance appear to be similar, marked distinctions arise. For example, we frequently strike at a fly biting the back of our hand, thinking it to be the common house-fly, while in reality the common house-fly has not the nec- essary mouth-parts to enable it to pierce the cuticle. Again, we might find two insects apparently widely separated by color, or structure, — distinctions due to the character in the sexes of the same kind of insect. Then if we change the food and surroundings of an insect, we soon find a subsequent generation of this in- sect changing in form and appearance. The sheep tick, a wingless, almost grub-like insect, was once a two- winged fly, but on account of its parasitic habits it has lost its wings through disuse. Other forms, such as the viceroy butterfly (Fig. 48, 6), have changed their outward appearance. If we remove an insect to a new country wre find changes arising, due largely to changed climatic conditions.
And so in classification, we find it difficult at all
WEALTH OF INSECT LIFE 163
times and under all circumstances to recognize forms possessing blood relations sufficiently intimate to enable them to reproduce in kind through successive genera- tions. We must not expect or look for absolute identity among individuals of the same species or kind. We should be satisfied with an agreement in the most es- sential features. Then if the question arises concern- ing the essential features of a character, it will have to be said that the cssentialness of a character is to be found in the constancy of its reappearance as successive generations come forth. Upon such considerations is a species based.
But as has been suggested, species themselves change. Within species we find varieties, which in time, we may suggest, will continue to vary, for one or several of the reasons stated, in a fixed direction until their essential characteristics will be so diverse from the mother species as to constitute a species themselves. There seems to be a tendency in nature to encourage, as it were, this divergence. If all forms of one species of insect were identical, all would be common prey to the same ene- mies. That is, if a certain parasitic insect or bird al- ways attacked a certain species, these being all the same, none would escape through the faulty recognition of the enemy. But since this tendency to vary exists, some escape by reason of dissimilar features, which enables them, temporarily at least, to elude the recogni- tion of the enemy. And so those escaping by reason of these variations are consequently liable to reproduce these variations in their offspring, until the variations become fixed. Under such circumstances we consider that a species has been developed. Individuals, then,
16-i ELEMENTAEY STUDIES IN INSECT LIFE
which constitute a species are those which do reproduce in kind through successive generations. To ascertain the powers of insects in this direction would be a very difficult task. So for the most part, at present, specific distinctions are based upon characters which, being present in a large number of closely allied individuals, are considered constant.
Groups of closely allied species are arranged to- gether under one genus ; then closely allied genera are placed in a group called a family; and families with leading characteristics in common form an order; and orders, for the same reason, compose a class ; and classes a branch; and branches a kingdom. This may be termed artificial ; and in part the arrangement is arti- ficial, but the endeavor is to discover the natural group- ing. The classificatory position, then, for instance of our familiar robin, might be sketched thus:
ANIMAL KINGDOM.
Branch, Chordata (Vertebrata). Family, Turdidse. Class, Aves. Genus, Merula.
Order, Passeres. Species, migratoria.
The term Robin is the common or vernacular name ; the scientific name, the one intelligible to ornithologists of all nations, is Merula migratoria. And so in speak- ing of any one form two names are required, the first to designate the genus, and the second term the species. Varieties are known as subspecies, races, or varieties.
It will be our purpose to acquaint the student with the principal orders and families of insects, and in so doing the attention is called to the steps to be taken from order and family before species is reached. The system used is an old one, and takes for its basis of
WEALTH OF INSECT LIFE 165
differentiation the character of the organs of flight, and the structure of the mouth-parts. Exceptions to the arrangement can be found in every order given. The same may be said of any system thus far proposed. This method commends itself for its simplicity and the uniformity of its nomenclature.
Insects, then, according to this system are grouped into nine orders, and the names of these are formed of words compounded with the Greek root, vrrepdv, pteron, meaning wing. These are: Aptera, ISTeurop- tera, Orthoptera, Tliysanoptera, Hemiptera, Lepidop- tera, Coleoptera, Diptera, and Hymenoptera. The character of the mouth-parts is designated by the terms biting and suclclncj, the former referring to that form of mouth in which the mandibles and the maxilke, or either one, are used in grasping, biting or masticating the food; the latter pertains to that form of mouth adapted for sucking. A discussion of the chief char- acteristics of these orders is given, and some of the more prominent subdivisions, as well as characteristic forms, are briefly treated.
APTERA.
This term, Aptera, is derived from a, without, and TrrepoV, pteron, a wing. The insects coming under this order are therefore wingless. Mouth-parts mandibulate, metamorphosis slight, the adult form being the same as the larval form. They have a delicate outer skin, sometimes covered with scales. Though somewhat primitive in form, they are so diverse in their individ- ual structures that it is difficult to frame a definition which will include all the group. While it is true that
1C6 ELEMENTARY STUDIES IN INSECT LIFE
all are wingless, the order does not include all insects without wings. The term wingless, as used in reference to the Aptera, designates those forms, wingless in them- selves, and descendants of ancestors which at no time possessed wings. Among the winged orders, wingless forms are found. Such forms, it is believed, have -de- scended from winged ancestors.
The Fish Moth.1 — Of this order the forms which tlio student will most likely meet will be those frequently found in the pantry, in dark closets and damp places. House- wives frequently term them fish moths. If an examination with a microscope be given, they will be found to be covered by shiny scales not unlike those of a fish, and these scales frequently give them a silvery appearance as they move away
FIG. 126. A fish . .
moth. (Leptsma when disturbed. They are sometimes 8p° called bristle-tails, by reason of the three
long bristle-like appendages at the caudal end of the body. (Fig. 126.) While some forms live in the house in pantries and in book-cases, or behind wall-paper, feeding upon starchy substances wherever found, others are to be found out of doors under stones and loose bark. The Springtail.2 - - The springtail is the common name given to another group belonging to this order, so called by reason of its ability to spring suddenly. This power is given it by a tail-like organ attached to the end of the body. This tail extends beneath the
1 Suborder, Thysanura. - Suborder, Collembola.
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body almost to the head. (Fig. 127.) When this is straightened out the insect is propelled several feet forward. Frequently num- bers of these little crea- tures like minute specks Fl(i. i27. springtaii (corUnothri.r bo- can be seen upon snow. To «°K8>- (^ter Tullberg.) such the name snow-flea is applied.
NEUROPTERA.
Insects with two pairs of membranous wings, bit- ing mouth-parts, metamorphosis complete in some di- visions and in others incomplete. The name arises from vevpov, neuron, nerve, and Trrepdv, pteron, wing. The wings, accordingly, are in many cases noticeable for the great amount of net-work. The front wing and the hind wing of the same insect are frequently alike in form, texture, and neuration. This order includes many heterogeneous insects, and is an order which has been subdivided by some authorities into a number of other orders. It includes such forms as the dragon-fly, May-fly, stone-fly, white ant, caddis-fly, and lacewing- fly. A wingless form, the bird-louse, is included here. A better understanding of the scope of the order will be gained by a treatment of a few representative forms.
May-Flies.1 — These insects, as the illustration will show (Fig. 128), are characterized by two pairs of membranous wings, the hinder pair being much smaller than the front pair, and by the presence of two long, thread-like abdominal appendages. They are peculiarly
1 Family, Ephemerida-.
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ELEMENTARY STUDIES IN INSECT LIFE
interesting insects in the matter of their life his- tory. The adult has an ephemeral life, lasting for a day or so at most. The females of some species drop their eggs upon the surface of the water, and others drop
their eggs beneath the surface on stones. The young nymph — not at all like its parent — hatches and lives in the water, feeding upon water plants or minute insects for from one to three years according to the species. They come forth at maturity, and can be found in great numbers in the warm summer evenings around the electric lights or upon the trunks of trees in the vicinity of water. Catch one of these adult forms and note the delicacy of its body. Examine its mouth-parts, and note that they are extremely rudi- mentary or even wanting, a condition brought about by disuse, since the life of the adult has become of such short duration that the necessity for taking food is no longer urgent. These insects are exceptional in their life history, since they molt once after having reached the winged stage.
Stone-Flies.1- - In structure of wings these insects resemble the May-flies. The net-work of the veins
'Family. Perlidce.
FIG. 128. A May-fly. From a photograph. Enlarged.
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is frequently much less, and the hind wings are- always more fully developed, folding in plaits on the body when the insect is at rest. The mouth is fitted for biting, the parts frequently being rudimentary.
The form in which these insects are most readily observed is in the nymphal stage, when they can bo
FIG. 130. A stone-fly (Perla ephyre).
FIG. 129. Stone-fly nymph.
found under rocks, stones or logs in brooks. They are not at first observed, so closely do they cling to the overturned stone or log. Remove some of them to a bottle of water. How many legs have they ? Of what use are those fringes along the under side of the body ( The White Ants.1- -While these are called ants, they are not closely related to ants. Like ants, however, they are social, and are represented by queens, kings, workers, and a form not found among ants, — the soldier.
'Family, Termitidce.
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FIG. 131. White ants. Sol- dier on the left, worker on the right.
The workers, as the term sug- gests, perform the labors of the colony. The soldiers are the de- fenders of the home. Upon the king and queen depends the in- crease of individuals.
Kings and queens are winged. In May and June those indi- viduals belonging to our spe- cies in this country leave the nest by flight and select new locations. A king chooses a queen. They shed their wings. If perchance a few workers find them and adopt them, the workers will build a circular cell for protection and furnish them food. This proced- ure forms the basis for the establishment of a col- ony. Since workers do not always discover and adopt these noted individ- uals, many kings and queens perish unattended. Should a colony become queenless, wingless, sex- ual individuals, compli- mented kings and queens, are produced. Such females are unable to lay many eggs, and here we find sev- eral of these required in the colony to fill
FIG. 132. A king white ant. En- larged.
FIG. IBS. white
ant queen, from
Africa - natural Ph°"
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FIG. 134. Nest of white ants on post, denoted by arrow on left ; locality, Cuba. Photographed by M. V. Slingerland.
FIG. 135. White ants' nest on trunk of tree, denoted by arrow on right ; lo- cality, Cuba. Photographed by M. V. Slingerland.
172 ELEMENTARY STUDIES IN INSECT LIFE
the place of a properly developed queen. In this coun- try white ants are to be found under logs and stones, not infrequently associated with our common ants. Here they do not grow so large, nor are they so numerous as they are in tropical countries.
Dragon-Flies,1 or " snake doctors," frequently so called, are familiar objects about ponds and quiet streams. In some species the females skim along over the sur- face of the water, dipping down to the water to drop an egg, there to hatch, and, in the form resembling
FIG. 136. Dragon-fly (Libellula pulchella')— natural size. From a photograph.
the figure (Fig. 140), to seek a livelihood. Other females oviposit by descending some water plant until the tip of the abdomen is below the surface of the water, there placing the egg in a slit cut in the plant for the purpose.
Among the weird superstitious beliefs of childhood, and not infrequently of later years, the dragon-flies have a place. Nearly every boy will tell you that the
1 Family, Libellulidce.
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chief end of this insect is to feed the snakes which lie in wait for him. It is a " snake-feeder " in the boy's parlance. Children generally are wont to fear this insect; they call it the " devil's darning-needle." They have been told -- and they believe it --that the long tail-like abdomen is a needle with which the insect sews up children's ears.
Entirely at variance with these strange tales, the insect is not only harmless but highly beneficial, since one of its chief sources of food is the mosquito, with whose piercing propensities all are fa- miliar. When the day is clear and still and the vertical rays of the sun make one content to rest a while in the shade of some spreading elm near the pond lily's home, or down by some sluggish stream, then it is, and there, that the dragon-flies are most active, — skimming along over the water, darting up, then down, right about face, all so quickly that at times the eye can scarcely follow. Suddenly that rests its wings one of them may halt to rest upon a stick alongltsback' The
*' dragon-fly rests its
or stump rising above the surface of the wings at right an- gles with its body.
water, or a dead limb overhanging, — to rest, probably, but more likely to train the eyes on the surrounding space in quest of passing mosquitoes or buzzing flies to be swooped down upon. Thus these dragon-flies are sometimes called " mosquito-hawks." Not unlike the raptorial birds, dragon-flies appear to have a certain stick or stump as lookout for prey. If
FIG, 137. A dam- sel-fly, a Libellulid
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ELEMENTARY STUDIES IN INSECT LIFE
the dragon-fly is disturbed it will fly away, to return shortly. This trait furnishes excellent opportunities for taking its picture in its native haunts. The perch discovered, the camera can be set and focused ; when all is quiet the insect will return, and the mere pressure of the bulb furnishes a plain picture such as this pho- tograph, taken in a similar way.
The dragon-fly's biogra- phy, could it tell it, would be full of strange incidents and hairbreadth escapes. It comes from a tiny egG', dropped alone in some large pond to hatch and grow. Two problems at once are presented - - to secure a live- lihood and to escape its hos- tile water neighbors, among them the fish and other members of its kind, both ready to feed upon it. It first lives upon micro-organ- isms of the water, but later becomes much larger and stronger and able to capture " wigglers " such as are to be found in rain-barrels. Its under lip is well adapted for this work; it is scoop-shaped, capable of extending and scooping in a wiggler and then drawing the catch up to the mouth, where the jaws make short work of it. (Fig. 139). And if perchance alone and unaided it has been able to escape its enemies and secure enough food to bring it
FIG. 138. Dragon-fly on the look- out for prey. Photographed from life.
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to the fullness of that water stage, it ascends some reed dur- ing the night, and about dawn its back breaks open and out creeps slowly and apparently painfully the dragon-fly, perfect in form but limp and colorless. The bright sunlight, already appear- ing, soon hardens its skeleton structure and brings out the characteristic colors of the par- ent insect which dropped the egg in the pond.
Mallophaga.1 — Bird-lice have, by reason of their parasitic hab- its existing through a long pe- riod, become so highly special- ized as to have little in common with other members of the group. Bird-lice must not be confused with true lice. The former have biting mouth-parts, the latter haustellate. The word Mallophaga is derived from two Greek words, meaning, to eat wool. These insects have incomplete meta- morphoses, are wing- less, and as external par- asites feed upon the feathers, hair or skin of the host. Thev are
i/
to be found upon both birds and mammals.
FIG. 139. Side and top view of head of nymph of dragon-fly, showing scoop-shaped jointed appendage of lower lip, with pinchers at end. With this the nymph catches "wigglers" and other prey.
FIG. 140. Skin of nymph from which dragon-fly has emerged.
FIG. 141. A bird- louse (Eurymetopus taurus.) This form lives among the feathers of the al" batross.
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ELEMENTAEY STUDIES IN INSECT LIFE
Caddis-Flies.1- - These moth-like insects, small and rather unattractive, are not frequently noticed. Though possessed of two pairs of well-developed wings, they do not use them readily in flight, so that the adults rarely wander far from their place of emergence in some stream, brooklet, or pool. The mouth-parts of the adult are rudimentary, the metamorphosis com- plete. The eggs are deposited in a mass surrounded by jelly. Sometimes this mass contains as many as one hundred eggs.
FIG. 142. A caddis-fly (Leptocerus dilutus).
Of greater interest than the adult, will be, to begin- ners, the larva and its habits. The young caddis-worm protects itself from fish and other enemies by con- structing a house of sticks, pebbles, leaves and the like, to be found in the water where it lives. The figure (Fig. 37) represents but one of the many interesting houses. Among the stones through which the waters of a small stream is running such forms live.
ORTHOPTERA.
Insects of this order have biting mouth-parts, two pairs of wings, the front wings being generally narrow and the hind wings of more delicate texture, and fold fan-like under the front wings; incomplete metamor-
1 Family, Phryganeidae.
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FIG. 143. The home of the stone-fly and the caddis-fly.
phosis. It includes such forms as the cockroach, ear- wig, praying mantis, walking-stick, cricket, katydid, and grasshopper. The term is derived from opftfe, orthos, straight, and Trrepdv pteron, wing. —12
178 ELEMENTARY STUDIES IN INSECT LIFE
ORTHOPTERA THAT WALK.
Cockroaches.1- - These insects are known to every housewife. They are most active at night-time, and readily learn the paths leading to the pantry shelf. The eggs are all laid at once, within a brown capsule. (Fig. 121.) Many species are wingless.
Praying Mantis.2- - The Praying Mantis possesses many appellations. The fore feet, well developed for
FIG. 144. Young mantis on lookout for prey — natural size. Photographed from life by M. V. Slingerland.
grasping, the elongate prothorax and prominent head, capable of rotary motion, certainly give these insects, to say the least, a strange appearance. They are rather sluggish in their movements, except when an approach- ing fly reaches a point within their grasp. All these insects are carnivorous. The eggs are laid side by side until they form a mass upon some object such as a fence- board, rail, or limb of a tree. The young escape readily, leaving the egg-mass in form but showing the openings from which the insects come. The mantis family vary in color from dark brown in some to light
1 Family, Blattidce. " Family, Mantidce.
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green in others. Some of these insects illustrate pro- tective characteristics to a high degree in their resem- blance to leaves of trees. Such forms are confined to the tropics.
" Praying mantis," " praying horse/' " mule-killer," " devil horse," " rear horse," and " camel cricket " are
FIG. 145. Full-grown mantis patiently waiting or "praying" for an oppor- tunity to seize any small, unwary creature. Natural size. Photographed from life by M. V. Slingerland.
a" partial list of the terms referring to the insect repre- sented in the figure. It has been called by scientists, Phasmomantis Carolina. The attitude doubtless ac- counts for the modifying term " praying." " Rear horse " and " camel cricket " have some reference to its shape. The term " mule-killer " arises from the superstition that the dark-colored saliva which the in- sect ejects from its mouth is fatal to the mule. It is
180 ELEMENTARY STUDIES IN INSECT LIFE
not easily understood how those familiar with the char- acter and temperament of the mule could readily put their faith in this doctrine.
This formidable-appearing insect can sometimes be found in a quiet corner of the window, in an attitude somewhat like the one here shown. If prayer there be, the petition is surely for the approach of an unwary house-fly to be readily pounced upon for the next meal. This insect is perfectly harmless.
Walking-Sticks.1- -Walking- Sticks likewise possess characteristics which unquestionably protect them and thus favor their existence. Their long, stick-like bodies and inactive disposition allow them to simulate sticks ; or when on trees, the twigs. In the tropics we find the wings of some of these forms simulating leaves. The common form in the North is wingless. The walking- sticks are vegetable-feeders. The eggs are dropped singly upon the ground. (See Fig. 47.)
The foregoing proceed by walking or running ; crick- ets, grasshoppers and katydids have the hind legs fitted for leaping, and while capable of walking they generally move about by jumping.
ORTIIOPTEEA THAT JUMP.
Crickets.2 — Crickets are to be found in the harvest- field, under the shocks of grain, and around the stacks. Not infrequently one enters the house, and then, if it be a male, his clear, shrill "click, click" (page 45), his mate-call, notifies you of his presence. These are the familiar black crickets, that live mostly upon the ground. The family contains two other kinds — the
1 Family, Phasmidce. - Family, Gryllidoe.
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mole crickets, which live under the ground, in burrows of their own making, feeding upon the tender roots of plants ; and tree crickets, which live above- ground, in bushes and trees. In the early spring the eggs of one of the tree crickets can be found in the raspberry canes. (Fig. 36.)
Katydids.1 - -Katydids, like- wise, are musical, night being their time for song. (Page 44.) They live in trees, and from their color resemblance to foli- age are not readily observed. Belonging to this same family are others, which resemble grasshoppers. Such are
FIG. 146. A mole cricket (Gryllotalpa borealis) — one and one-half times natural size.
FIG. 147. Angular-winged katydid — natural size.
easily distinguished from grasshoppers by the length of the antennsc, which are longer than the body. This
1 Family, Locustidce.
182 ELEMENTARY STUDIES IN INSECT LIFE
group, then, is sometimes called the long-horned grass- hoppers. Grasshoppers proper have antennas shorter than the body.
Grasshoppers.1 — Grasshoppers are among our most common insects. The life history of one of the spe- cies has already been given. (Page 3.) Those living in this country can be separated into three groups, depending upon the structure of the adult. One group embraces all those without extended ridge on longitudinal median line of pronotum, and bearing tubercle on center of prosternum (Acridiince). The yellow grasshopper (Melanoplus differentialis} is an ex- ample. The second is without prosternal spine, and has an extended ridge upon the pronotum (Oedipodince}. The '" dusty hoppers," so common in the roadways, be- long to this group. The third are not so generally known, but are easily recognized by the backward and downward receding front of the head (Tryxalince}.
THYSANOPTERA.
These insects have four long, narrow, membranous unfolded wings, well fringed with hairs, from which the name of the order is taken. There are few veins. The wings at rest lie horizontally along the back. The mouth-parts are imperfectly fitted for sucking, being intermediate in form between those of the Orthop- tera and those of the Hemiptera. The metamorphosis is incomplete.
The name of the order arises from Ovaavos, thysanos, fringe, and Trre/oo'y, pteron, a wing. These minute in- sects are to be found under the bark of trees, in the
'Family, Acrididce.
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FIG. 148. A thrips. Greatly enlarged.
heads of grain, timothy, clover, and in flowers, especially such as the daisy. The majority of this order are plant- feeders; a few are predaceous. These insects, commonly called thrips, are scarcely visible to the naked eye. They are about one-twelfth of an inch long. When the head of a daisy has been rubbed in the hand, a lens will be needed to clearly observe the insects, and even then the observer may require a com- pound microscope before the fringed wings can be clearly perceived. HEMIPTERA.
It is customary among people in general to speak of all insects, or forms resembling them, as bugs. The term can properly be applied only to the members of this order. These have incomplete metamorphosis, haustellate mouth-parts, four wings. The Hemiptera or true bugs include some of our most injurious forms. The term is derived from ?;/•«, hemi, half, and Trrepov, pteron, wing. The order contains a number of forms widely diverging from the general type, so that the group is best understood when resolved into two fairly well-defined suborders, — the Heteroptera and the Homoptera. The Heteroptera are those with front wings of an unequal texture, the basal half being the heavier, the outer half not infrequently translucent. It is also characteristic of this suborder that the beak rises from the front part of the head. The Homoptera com- prise those with wings of like texture throughout, and beak rising from the ventral portion of the head.
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ELEMENTARY STUDIES IN INSECT LIFE
FIG. 149. Box-elder-bug (Lepto- coris trivittatus). Enlarged.
The Heteroptera Among the Heteroptera are the
chinch-bug, the squash-bug, the box-elder-bug, and the assassin-bug, living on land; and the giant water-bug, the water-strider, and the back-swimmer, living in the
water. Those land forms which have been mentioned, with the exception of the assassin-bugs, live upon the juices of plants. The assas- sin-bugs lie in wait and seize upon other insects, pierce their prey, and draw there- from the lifeblood. Those living in water are all pre- daceous.
Giant Water-Bug.1 — When electric lights came into general use for street illumi- nation, there frequently appeared around them an unus- ually large insect. Great numbers of such insects were wont to congregate around the lights, and they soon became known as " electric-light bugs." This insect in
reality is one of the aquatic forms of this order. It is predaceous. It darts out from some cranny nook in brook or pond to catch small fish, tadpole, or other aquatic insect. Having secured its prey, this giant water-bug drives in its beak and leisurely regales itself with the
'Family, Belostomidce.
FIG. 150. An assassin-bug (Melanolestes pioipes), showing strong beak and large fore legs fitted for grasping.
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FIG. 151. Giant water-bug (Bena- cus griseus) — natural size.
blood of its victim. This insect is harmless, but would readily use its beak in self-defense.
The Homoptera includes such forms as the cicada or harvest-fly (sometimes erro- neously called locust), the buffalo tree-hopper, aphids or plant-lice, and scale insects. Of all the insects in this or- der, possibly the plant-lice and scale insects are the most unique in their development. The plant-lice, in addition to a very peculiar mode of development, have with- in their family certain spe- cies which secrete a kind of honey much appreciated by certain ants; and as these ants have now come to
rely upon this as a means of subsistence, they have in many cases adopted, as it were, the plant-lice, and care for them by moving them about to the tenderest parts of the plants from which the aphids draw their nourish- ment. And in turn the aphids, from
FIG. 152. Cicada and cast-off nymphal cov- 1 , ,
Wins-natural size. From a photograph. «>ng attention by tllC
186 ELEMENTARY STUDIES IN INSECT LIFE
ants, have become dependent upon the ants. This illustrates the effects of use and disuse. Undoubtedly
«/
the aphids were once independent and self-supporting
FIG. 153. Newly hatched scale insect. Greatly enlarged.
and unattended by ants. Had the ants never under- taken the care of these aphids in the first place, the
aphids would still be in full possession of all their powers and instincts ; but the ants having through many gen-
FIG. 154. Protective covering of female scales p
(Aspidiotus greenii). CratlOUS aSSUmed tllC
care-taking responsibility, this faculty or instinct of the aphids, not being used, has evidently been lost. Ants running up and down trees are not infrequently going to and from these aphid pastures. Among the plant-lice
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we find winged individuals, capable of carrying the spe- cies into new localities, and wingless forms whose sole duty is the reproduction of their kind.
Among; the most anomalous forms of insect life
o
FIG. 155. Adult female scale insect (Kermes ni- valis) living oo oak twig, showing a form which does not secrete a pro- .
tective covering. En- larged. Photographed
from nature.
FIG. 156. An unprotected scale. Adult female scale
insect (Lecanium aurantiacum) living on osage-orange branch. Enlarged.
are the scale insects. The young either come forth from eggs or are given birth, both sexes at first being alike, resembling mites (Fig. 153), and subsisting upon the juices of plants and trees. As they develop, the males go through complete metamorphosis, and emerge as insects with one pair of wings, but without mouth- parts. The female passes through an incomplete meta-
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ELEMENTAEY STUDIES IN INSECT LIFE
morphosis. After the first molt she loses her legs, antennae, and eyes, and remains stationary as a footless
FIG. 157. Adult female scale insect (Kerm.es pubescens) living on oak twig. An unprotected scale. Enlarged. Photographed from nature.
grub upon the host, there to draw sustenance and re- produce her kind. Some female forms of these insects, however, retain the power of locomotion. Many of
FIG. 158. Protected scale in- sects. Scales under which fe- male scale insects (Diaspis snowii) live. These scales are formed from a waxy substance which is an excretion from the back of the scale insect's body. The scale does not adhere to the insect's back.
FIG. 159. Protected scale insect. Scales which cover the male scale (Diaspis Snowii) during its metamorpho- sis.
these footless females are well protected by an outer scale (Fig. 158), which is formed by an excretion from the dorsal part of the body. Others are naked. (Fig. 157.) To the former kind belong the noted and injurious scale com- monly known as the San Jose scale.
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FIG. 160. Adult male scale Insect (Aspidiotus an-ylus). Enlarged. Drawn by Miss M. E. Wise.
The true lice, those that live as parasites upon the skin of mammals, belong to the Hemiptera. Some authorities place them in a separate suborder called Parasitica.
COLEOPTERA.
These insects possess well- defined mandibnlate month- parts. The wing-covers are horny and do not overlap, but meet along the median line of the back. The wings proper, the ones most useful in flight, are delicate, mem- branous, and are concealed beneath these wing-covers. The metamorphosis is com- plete. These insects are
. TI j i i f'10' 161- A water scavenger (Hy-
commonly called beetles, aropMius trianauiari»). XH.
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ELEMENTARY STUDIES IN INSECT LIFE
and include such forms as the June beetle, the lady- bird, the potato beetle, the fireflies or lightning-bugs, and the plum curculio. The Coleoptera are not likely to be mistaken for those of any other order. The term arises from two Greek words, /coXe'o?, coleos, meaning sheath, and Trrepdv, pteron, wing.
FIG. 162. A click beetle (Alaus oculatus). From photograph. X
Basing
FIG. 163. Wood-boring beetle at work in yellow-pine board. Photographed Jfroin life by W. O. Stevens.
the classification upon the mouth-parts, the order is divided into two groups : the true beetles, such as the June beetle and the ground beetle (page 277), — those with typical mouth- parts ; and those with mouth-parts developed into a long snout, such as the plum curculio, and the snout beetle illustrated in the figure. (Fig. 1G4.) The order em- braces a large number of species, and a number of these are of common occurrence. Some forms, such as the tiger beetles, the ground beetles, whirligig beetles (or " lucky
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bugs "), are predaceous. Other forms, commonly called borers, are such, as the apple-tree borer, the pine-tree borer (Fig. 163), and the cottonwood borer, the larva of which live within the trees named. There are likewise
forms which feed upon
leaves, such as the potato beetle and June beetle. A few abnormal species are parasitic upon bees and wasps. Those whitish FlG 164 A Bnout beetle (9phmopho. grubs found when spading, rus «*«««)-twice natural size, or when in quest of angleworms, belong to the June- beetle family. The eggs from which they emerge are laid beneath the surface of the ground, to hatch within a month to feed upon tender rootlets, or decayed vege- table matter. In autiimn they hibernate below frost line ; in May they pupate near the surface ; in June they emerge.
The familiar ladybird larvae are for the most part predaceous, feeding upon other insects, especially plant- lice and scale insects ; consequently the black or spotted lame are to be found running around upon plants and trees. (Fig. 107.) Pupation takes place with the pupa pending by the abdomen from leaves, fences, or trunks of trees.
LEPIDOPTERA.
These are insects which have long been the recipients of popular attention. They possess haustellate mouth- parts, which take the form of a spirally rolled proboscis, four wings, similar in structure, and covered with minute scales. The metamorphosis is complete. The
192
ELEMENTAEY STUDIES IN INSECT LIFE
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WEALTH OF INSECT LIFE
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larvse of these insects are commonly called caterpillars. Lepidoptera is composed of two Greek derivatives: XeTrt?, lepis, scale, and irrepov, pteron, wing. These scale- winged insects are divided into moths, skippers, and butterflies, dependent upon habits and structure of the antennae. (Figs. 167, 169, 170.)
FIG. 166. The "humming-bird" moth (Phlegethontius celeus) with proboscis extended, to show its length — about one-half natural size. From a photograph.
Moths. — Nearly all moths are night-flyers. Some fold the wings when at rest, longitudinally and fre- quently roof-like upon the side of the body; others retain the wings horizontally. Many moths find pro- tection in their color resemblance to objects upon which they rest.
Skippers are so called from their uneven manner of
flight; when resting upon some flower or damp spot —13
194
ELEMENTARY STUDIES IN INSECT LIFE
on the ground they impress one as extremely nervous beings. The wings keep moving from vertical to hori- zontal and back again. If there be a momentary rest it is generally with the wings held vertically. Some- times the front wings are held vertically while the hind wings are resting horizontally. One unacquainted with the manner of flight might suppose the insect to
FIG. 167. Luna moth (Actias luna), showing form of moth antennae. ^a
be a wounded butterfly, so irregular and spasmodic is their mode of action when on the wing. Their antennae are also characteristic. (Fig. 169.)
Butterflies are day-flyers, and are more slender in body than either moths or skippers. The wings are generally held vertically when at rest. The antenna are also distinctly characteristic. (Fig. 170). The life history and the habits of one of these has been illustrated elsewhere. (Pages 13-23.)
WEALTH OF INSECT LIFE
195
<
FIG. 168 "Pitcher" pupa of "humming-bird" moth. In the larval stage, this insect is to be found as a large green caterpillar on the tomato vines. Natural size. From a photograph.
FIG. 169. A skipper (Eudamus [TVwrybes] bathyllus), showing recurved tips of antennae — natural size.
V
FIG. 170. Interrogation butterfly (Grapta interrorjationis\ showing form of antenna in butterflies. (Figs. 38 and 39 illustrate larva and pupa of this butterfly.) From photograph.
196
ELEMENTAEY STUDIES IN INSECT LIFE
FIG. 171. bids) and
A fly (Sarcophaga cim- its pupa-case, showing
DIPTERA.
Insects with haustellate mouth-parts, front wings membranous, hind wings replaced by knobbed processes called halteres. The- metamorphosis is complete.
The name is derived from 5 dis, double, and Trrepdv, pteron, wing. The Diptera include all insects which can properly be called flies. Such forms as the house-fly, the mosquito, and the horse- fly are Diptera. While the mouth is fitted for sucking, in some flies such as mos- quitoes that organ is fitted for piercing the skin and sucking the blood. The or- der is a large one, and the species differ much in man- ner of life. The larvae are commonly called maggots. The females generally lay their eggs in the vicinity of the proper food for the maggot. Our common house- fly prefers fresh horse-manure for oviposition. Upon this the maggot feeds about a week, then transforms into the pupal stage, remains so for about another week, and then comes forth as a two-winged insect to find its way inside mosquito-barred doors and windows, or into dwelling-houses not properly guarded.
The method of emergence from the pupal case is -of interest. The larvae of more generalized forms such as the robber-fly, come forth from a straight seam in the side of the case, and in this differ not at all from the mode of many other insects. In the case of the more
bursting off of end of pupa-case to be its method of emerging. Enlarged.
WEALTH OF INSECT LIFE
197
FIG. 172. Robber-fly (Erax cinerascens) — one and one-half times natural size.
specialized forms, such as the house-fly, when they are ready to escape there forms upon the front of the head a sort of balloon, which blows off, as it were, the end of the pupal case, and al- lows the fly to walk out. Then the bladder - like forehead gradually re- cedes and the head be- comes normal.
Fleas.- -These aberrant insects are by some authori- ties placed in a separate order ; by others in a suborder of the Diptera. They are wingless insects, with body compressed, legs well developed, and adapted for jump- ing. The female lays about a dozen eggs. These are
deposited in the dust accumu- lated in cracks and crevices. The larvae have a head and jaws, and feed upon decaying bits of animal and vegetable matter found in the crevices where they live. Their pupal stage is passed within a cocoon spun by
the lar/a. The mouth-parts of the adult are fitted for piercing and sucking. Among domestic animals they are to be found upon the cat, dog, rabbit, poultry, and pigeons. There is a species which lives upon the cat and dog --a flea which at times also proves annoying
FIG. 173. A flea (Ceratopsyl- lus serraticeps). Enlarged ten
times.
11)8
ELEMENTARY STUDIES IN INSECT LIFE
to man. In Europe there is a species of flea which is very troublesome to man. This species occurs some- times in this country.
HYMENOPTERA.
These insects have four membranous wings. The hind wings are smaller than the front wings. Man- dibulate mouth-parts, in many cases accompanied by
FIG. 174. A wood-boring hymenopt'eron, the pigeon horn-tail (Tremex columba) — natural size. From photograph.
proboscis ; metamorphosis complete. The name arises from two Greek words, vprfv, hymen, membrane, and irrepdv, pteron, a wing.
This order includes the bees, ants, and wasps, well- known forms, remarkable for their social habits and marvelous instincts. The order may be divided into three groups, divisions based largely upon the habits of the insects.
Plant-eating Hymenoptera are those whose larvae have feet, and are capable of moving about in quest of food; they somewhat resemble caterpillars. The meta-
WEALTH OF INSECT LIFE 199
morphosis is similar to the metamorphosis of Lepi- doptera, except that the pupal case is soft and assumes no hard outer skin. They feed upon plants. Such is the rose slug, that greenish worm with delicate skin, which, feeding mostly at night, skeletonizes the rose- leaves. This work of the slug gives the bush a decidedly fire-burnt appearance. This group is commonly called " saw-flies," because of the two saw-like processes of the ovipositor. The larvse of some other members of this division bore in wood. The adult insects of this divi- sion can readily be distinguished from the two subse- quent groups by the broad basal union of the abdomen with the thorax, the caliber of the basal segments of the abdomen being about such as is usual in insects of the same size. The two groups which follow have the ab- domen connected to what appears to be the thorax by a slender stalk. On account of this peculiar joining of the two parts of the body we find such terms in use as " thread-waisted wasps."
Parasitic Hymenoptera.— -Ichneumon-fries are the chief members of this second division, characterized by the parasitic habits of the larva. These larvse are usually parasitic within the bodies of plant-eating in- sects. If a society of caterpillars be watched for a short time, long, slender-bodied insects will be observed darting down among the caterpillars. Frequently after the insect has flown away some caterpillar in the assem- blage will be observed squirming and wriggling. It is endeavoring to cast off the egg just deposited upon its back. From this egg there will hatch a footless grub - why footless ? - - to feed upon the body liquids of the caterpillar. Since the vital portions of the host are not
200
ELEMENTAEY STUDIES IN INSECT LIFE
generally attacked, the caterpillar frequently pupates; and so, in collecting chrysalids, especially lepidopterous ones, for emergence, one or many of these hymenoptera, instead of the form corresponding to the pupal case, may come forth from the case.
Fio. 175. Parasitic hymenopteron (Thalessa lunator) drilling with ovipositor Into burrow of the wood-boring larva of the pigeon horn-tail. (After Riley.)
The accompanying figure (Fig. 175) illustrates a parasitic hymenopteron1 at work. This is one of the larger insects of the order. It is parasitic upon the wood-boring larva cf the pigeon horn-tail,2 another hy- menopteron. When Thalessa finds a tree infested by this borer, she selects a place which she supposes to be opposite the larva's burrow, elevates her long ovipositor in a loop over her back, and places the tip of the ovipos- itor on the bark of the tree. By raising and lowering
lThal$ssa lunator.
"Tremex columba.
WEALTH OF INSECT LIFE
her body she skillfully drills a hole into the tree. When the ovipositor enters the burrow she deposits an egg in it. The larva that hatches from this egg crawls along the burrow until it finds the wood-borer. This wood-borer is a soft-bodied larva. To this the young Thalessa fastens itself, and subsists upon its blood until ready to pupate. It pupates within the burrow of the horn-tail. Sometimes Thalessa is unable to extricate her ovipositor, and is held fast until she dies.
Stinging Hymenoptera. — Among these the female is with few exceptions provided with a sting at the end of the abdomen. Usually the f ootless - - why footless? — larvae are reared by the females in cells constructed for the purpose. To this group belong ants, bees, and wasps; these have been discussed elsewhere. (See pages 62-88.)
202
ELEMENTAKY STUDIES IN INSECT LIFE
CHAPTEK X
GEOGRAPHIC DISTRIBUTION AND THE STRUGGLE
FOR LIFE
IN the study of physical geography we are accus- tomed to continental maps illustrating land areas bounded and indented by water areas. In political geography, maps show the divisions and subdivisions of countries based upon artificial conditions. Animal geography is another branch of geographical science, in which maps are of value in defining the boundaries of the areas in which animal forms of definite classes exist normally.
Habitat. - - The geographical range of a species of animal or plant is frequently spoken of as the habitat of the species; that is, the region in which the species lives in a state of nature. From this it might be sup- posed that where the species is originally found there it thrives best, and that there the conditions are ideal for its existence. This is not necessarily so. Of the seventy-three species of insects which occur in the United States in such numbers as to be injurious to man's interests, thirty-seven have undoubtedly been in- troduced from foreign countries. Less than thirty years ago the eggs of the gypsy moth were imported into Massachusetts from Europe. The insect escaped from confinement. No particular attention was paid to this escape. However, in 1890, some twenty years after the introduction the State of Massachusetts
GEOGEAPHIC DISTRIBUTION
203
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found it necessary to appropriate funds for carrying on measures looking toward the permanent, reduction of the numbers of this insect. The caterpillars have continued to multiply and defoliate the trees each year. In remedial work against this insect the State of Mas- sachusetts has already spent over half a million dollars, and much more must be spent before a permanent check to its destructive increase can be assured. From these facts it is readily inferred that the boundaries of the habitat of a species are not constant, but are subject to change. Every species unwittingly strives to extend its territory, to gain more room to live, to disturb the balance of forces which holds all in restraint. In this, some species are successful, and extend their domain; others are not; they cannot hold their own; they oc- cupy less and less territory until they become extinct. Barriers. — Checks to the extension of range differ with different groups of animals. Most mammals cannot traverse oceans, nor can fishes cross continents. In- sects, however, have a wide- distribution. This group is represented in every part of the globe so far visited by man, from the extreme limits of the Arctic and Ant- arctic regions to the equator, and from the sea-level to altitudes far above the line of perpetual snow. Hum- boldt observed insects on Chimborazo at an elevation of 18,000 feet. They exist in fresh and salt waters, in subterranean caves and in hot springs, the waters of which reach moderately high temperatures. A cer- tain small fly (Psilopa] has been found breeding in petroleum, a substance formerly supposed to be fatal to insect life. In view of the vast numbers and varied forms of insect life, it is not so surprising that this
GEOGEAPHIC DISTRIBUTION
205
206 ELEMENTARY STUDIES IN INSECT LIFE
group exists over such a vast area and under such di- verse conditions. What has been said of the group as a whole cannot be said of the individual species in this group. They, in their attempt to extend their range, are subject to barriers. The barriers which restrict the spread of species of insects may be classed under two general divisions : (a) barriers which prevent en- trance into new territory; (6) barriers which prevent maintenance after introduction.
Barriers to Entrance. — Checks, such as oceans, or high mountain ranges, which affect many animal forms, are not always valid in the case of insect species. Insects surmount some of these obstacles through powers of flight, or are transported. While it is not possible for them to carry themselves across oceans or over high mountain ranges, they are frequently transported dur- ing quiescent periods such as the egg and pupal stages. The eggs, the pupa, or even the larva, of a wood-boring species, may drift in the heart of a log across an ocean. Through chance, mammals or birds may carry species of insects, during the quiescent stages of insect develop- ment, across possible insect barriers into new territories.
Barriers to Existence.— -Introduction into new terri- tory does not decide the establishment therein of the insect introduced. Climate is an important element in the life history of an insect. Some insects require a high altitude with its accompanying dry atmosphere and moderate heat. Others can exist only under con- ditions to be found in low lands with their marshes and humid atmospheres. The collector who studies the same locality for some time will notice that the in- sects dwelling in marshy meadows differ from those of
GEOGRAPHIC DISTRIBUTION
207
the rocky cliff. The Parnassian butterflies, alpine species, seem to require cool climate ; consequently they are to be found in northern countries and in the high altitudes of mountainous regions. The clouded skip- per butterfly seems to thrive in a warm, moist climate. Its habitat, then, in the United States is restricted to a strip of land along the Atlantic seaboard and the Gulf of Mexico.
While climatic conditions may not be unfavorable, there is still another barrier which in the case of many insects effectually prevents their spread. This is food plants. There are many insects, notably butterflies, which at some stage in their development are dependent upon a certain plant or family of plants for sustenance. The larvae or caterpillars of many butterflies will thrive only upon certain plants. If these plants are wanting in a new territory, it is evident that there will be no in- crease in the respective species. The milkweed but- terfly, already referred to under other phases, is a case in point. The caterpillar of the milkweed butterfly will grow and develop only when feeding upon the leaves of some member of the milkweed family. This insect belongs properly to the tropics, but has now a widespread distribution. It was unknown in Hawaii until a member of the milkweed family established itself in Hawaii. Similar observations have been made concerning its existence on a number of other oceanic islands subsequent to the natural growth thereon of the milkweed.
Fauna.— - The term " fauna " is used to designate the animal life of any district. The fauna of Iowa, for instance, refers to all the animal life in a state of nature
208 ELEMENTAKY STUDIES IN INSECT LIFE
within the borders of the State. The insect fauna of Iowa consists of all the insect life existing within the borders of the State. State lines, however, have no influence in themselves upon the distribution of species, so that the fauna of Iowa and that of the adjoining States of Missouri and Illinois would probably vary but little.
Zones of Life. — The continent of North America may be divided upon the lines of animal and plant distribu- tion into three primary transcontinental regions: Boreal, Austral, and Tropical.
The Boreal region covers the whole of the northern part of the continent, from the polar seas southward to the northern boundary of the United States. A nar- row strip along the Pacific coast and the higher por- tions of the Sierra Cascades, the Rocky Mountains, and the Alleghanies, all in the United States, are in this life zone.
The Austral region covers the whole of the United States except the Boreal mountains and the Tropical lowlands.
The Tropical region covers the southern part of the peninsula of Florida, the greater part of Central America, the lowlands of southern Mexico south of the table-land, and a narrow strip on each side of Mexico. This strip follows the coast northward into the United States.
The fauna and flora --that is, the animal and plant life — within each of these regions are not alike throughout the respective regions. They show striking differences. This has led to the subdivision of these principal zones into a number of minor areas based
GEOGEAPHIC DISTRIBUTION
upon the particular grouping of plants and animals. Maps are used to show zones of life. In like manner the habitat of each species can be mapped out. (See Figs. 170, ITT.)
Modes of Distribution — Little has been done in the study of the geographic distribution of insects as a class, because many of _ the groups are liable to be trans- ported by accidental causes, so that there is a tendency to consider their faunal areas quite unstable. Neverthe- less, among insects there are many species whose hab- itat is greatly localized, due in a measure to the extreme narrowness of the life habits of the species ; that is, they have become so adapted to a certain food plant, certain climatic conditions, and to association with certain other forms of animal life, that they can- not exist away from these set conditions. In the study of insect distribution, all these factors and conditions are to be considered.
The manner in which insects can be distributed in a state of nature are: over landed areas, by flight or travel, winds, transportation on birds, mammals or other animals; across seas to new lands, by flight, (in- sects have been met in flight three hundred miles from mainland,) transportation in egg, larval or adult stages, on driftwood. Commercial activities, instituted by man, greatly facilitate the spread of insects. In the first place, insects can be introduced intentionally, as in the case of the gypsy moth. They can likewise be, and more frequently are, accidentally transported. The frequency of commercial exchanges between mari- time powers, as well as the rapidity of the journey, —14
210
ELEMENTARY STUDIES IN INSECT LIFE
GEOGRAPHIC DISTRIBUTION"
211
greatly increases the possibilities of such means of transoceanic extension of species. Continental com- merce will likewise facilitate the spread of insects across continents. Insects which enter the hold of a lading ship can exist through a reasonable sea voyage. Their establishment in the new country depends upon the finding of suitable food, and the number and sex of the individuals of the species transported. It is possible that in the merchandise or the packing sur- rounding merchandise the majority of successful trans- portations are made. Especially is this true in the case of scale insects, since nursery stock furnishes not only means of transportation, but at the same time sus- tenance. The female scale, of limited powers of loco- motion, has in a state of nature limited distribution. Tiider present commercial conditions the spread of these insects has been unusually great. The San Jose scale was known in this country in 1S8S in California only. Through commercial traffic it now exists in more than thirty States of the Union.
Deductions. --In this study of distribution, light is thrown upon the subject of land relationships. It is fair to suppose that an island fauna, similar to the adjoining mainland, and whose similarity cannot be accounted for on the ground of transportation, can be accounted for on the ground of a previous land con- nection of the island with the mainland. If the fauna of an island differs materially from that of the near- est mainland, this seems to indicate a separation of great antiquity, or possibly a distinct separation of the two land areas from the beginning. The fauna of Madagascar, for instance, differs widely from the op-
212 ELEMENTARY STUDIES IN INSECT LIFE
posing mainland of Africa. This is due, it is believed, to the fact that Madagascar has been separated by water from 'the mainland since remote times. This be- lief is strengthened by the notable depth of Mozam- bique channel. From studies of this nature, together with geologic data, islands can be divided into two classes : continental, those once a part of the mainland, and oceanic, those which have never been connected with any one of the continents.
A study of the modes and possibilities of transpor- tation and introduction of insect life is further profit- able in determining the desirability of the entrance of species injurious to the interests of man. And if such inimical forms are introduced, it may be possible to determine the original habitat of the inimical forms and to seek their natural enemies. The question, then, becomes : Tan these insects be safely introduced to prey upon the injurious insect? As an illustration: The fluted scale some years ago promised fair to greatly curtail and possibly destroy the citrus trees of Cali- fornia. It was found after investigation that this scale was of Australian origin, and that in its native habitat a ladybird beetle, both in larval and adult state, preyed upon this scale. This beetle was successfully intro- duced into California, where it has curtailed the in- crease of the scale and consequently its damage to the citrus industries.
The Struggle for Life. — The progeny of a single fertile female San Jose scale insect for a single season, not reckoning mishaps, is over three billion individuals. The queen of the honey-bee hive during the working- season deposits from two to three thousand eggs daily.
THE STRUGGLE FOR LIFE 213
Five hundred eggs would be a small average for fe- males of the insect tribe. If all of these eggs were to bring forth individuals and all these individuals and their progeny were to continue the reproductive pro- cess, how long would there be sustenance for such myriads ? It has been estimated that if the eggs of a common house-fly should develop and each of its progeny should find the necessary condition for growth and development, without loss or destruction, the people of the city in which this might happen could not get away soon enough to escape suffocation from an atmos- phere filled with flies. Such conditions do not exist. Why not ? Are there certain persons detailed from each community to prevent undue multiplication ? Evidently not. If all these forms were to appear the food supply would soon be exhausted. The facts are that the percentage of eggs which develop into mature forms is very small. Unusually favorable conditions sometimes occur to permit a goodly percentage of the eggs to hatch and attain maturity. At such times we have plagues. The multitudes of maple-worms and grasshoppers which sometimes appear are illustrations. But these are not of regular occurrence. Since, then, all insects do not reach maturity, what determines which ones shall succumb and which ones shall live ? "All live who can." It is evident that there must be strife for existence ; that among insect forms as well as higher animal forms there is a struggle for existence, — a struggle which for the greater part is unconsciously carried on by the individuals concerned. Some are destroyed by mere accidents. Aside from this the struggle takes place: (a) Between individuals of
214
ELEMENTARY STUDIES IN INSECT LIFE
the same kind, contending for necessities of life, as grasshopper and grasshopper ; a " struggle between fellows." (6) Between insects of different kinds, the one endeavoring to devour the other, as grasshopper with parasitic fly or predaceons beetle ; a " struggle between foes." (c) Between insects and conditions of life, as the grasshopper and the unfavorable winter climate or the chance of securing proper nourishment in the early spring ; a " struggle with fate."
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FIG. 179. Long-winged grasshopper of the plains (Disaostei.ro, longipennis). In 1873 the female of this species was unknown to scientists. The knowledge of the existence of such an insect was based upon the finding of a male. From a pho- tograph.
To those who live there must be accredited some characteristics not possessed by those who perish. If such a characteristic protects or favors the life of the individual, this characteristic will tend to remove the individual from the intensity of the struggle. Traits of advantage which have been evidenced during this struggle are the "protective devices" discussed in Chapter IV, and chief among the others are: warning colors, parasitism, social organization, feigning death.
Warning Colors.- - The object of protective coloration is to conceal or disguise. The purpose of warning colors
THE STRUGGLE FOE LIFE
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is the very opposite, the retention of such coloration being to render as conspicuous as possible the form wearing them. Some of the most striking illustrations of warning colors are to be found among insects. The young collector will soon be able to divide insects into two general classes, — those difficult to distinguish from their surroundings, and those quite conspicuous. The protection does not lie in the colors in these cases, but in some unpleasant attribute connected with insects wear- ing such colors. Many hymenoptera, for instance, pos- sess stings. Stinging insects, we find, are rendered con- spicuous by warning colors such as the contrasted dark and yellow bands of the common wasp, the hornet, and of many bumblebees. The red and black ladybirds are quite conspicuous. These have been shown to be extremely nauseous to insectivorous animals. Some white moths and some moths made conspicuous by their white and black colors have been refused in disgust by insect-eating animals. Many caterpillars with the abil- ity to emit noxious juices are rendered conspicuous either bv striking colors or exposed positions upon their food plants.
Parasitism. — Hunger and the quest for shelter have doubtless led to the habit of existing as unbidden guests in or on plants, other insects, or higher animals. The one, a parasite, lives in or on the other, a host, securing the necessities of life from the host. The host gives up a part or all of its vital force to the parasite. Very few species of insects are exempt from the entertain- ment of parasites. Parasites themselves are parasitized. Among insects are to be found all variations of para-
THE STRUGGLE FOR LIFE
217
sit ism: the external parasite, as the sheep-tick, or the Lird-louse, external parasites spending the whole exist- ence upon the host; the ichneumon-fly, depositing its egg- upon the back of some caterpillar wherein the ich- neumon larva1 will dwell until pupation, then to emerge as a winged insect, an internal parasite for part of its existence. The advantages gained by the parasite are great, — abundant food, safety, and warmth, all neces- sities of its natural well-being. There are, however, disadvantages. The parasite tends to degenerate through disuse of organs. The sheep-tick was once a winged fly, but since it spends its whole life upon the same animal its wings were no longer used, and conse- quently were less and less developed. The female scale insect after settling upon plants becomes simply a living sac, a footless, headless grub, capable of digestion and reproduction. Parasitic insects that depend ex- clusively upon certain forms for existence lay them- selves liable to great reduction in numbers, even to ex- tinction. This is likely to occur should their host become greatly reduced in numbers, either through the attacks of the parasites themselves, or through other causes.
( 'hief among parasitic insects are the Hymenoptera. These prey largely upon vegetable-feeding insects, by dwelling as footless grubs in the bodies of the hosts, sub- sisting upon the so-called blood of the insect.
Among Hymenoptera there are some parasitic upon plants, and others are parasitic upon eggs of other in- sects. This subject of insect parasitism is of so great biologic importance as to be of vital interest to man
218 ELEMENTARY STUDIES IN INSECT LIFE
himself. Insects primarily depend upon vegetation for sustenance. So rapid are their powers of assimilation and so prodigious their efficiency for multiplication, that, were they to go on unheeded and unchecked, they would in the struggle for existence overcome mammals.
FIG. 181. Cecropia larva bearing cocoons of a parasitic insect, an ichneumon fly. ?3'.
Such is not the case, however. Insects are as a house divided, one part preying upon and destroying the other; the two succeed each other like wave upon wave. Parasites, finding innumerable insects to prey upon, increase so rapidly as to devour their means of support. They in turn succumb and the host rallies, only to be again defeated. So the struggle goes on forever.
Parasites do not confine themselves to forms gaining an independent livelihood, but attack those of like habits as themselves -- a phenomenon usually termed hyper-parasitism. jSTot only do parasites attack para- sites, but cases of secondary parasitism are numerous, tertiary parasitism is not rare, and quaternary para- sitism has been suggested as possible. Insect parasitism is of wide prevalence. A few years since the trees of the city of Washington, D. C., were almost wholly de- foliated by the white-marked tussock-moth. The great numbers of bodies of these insects attracted and fur- nished food for parasites, until in the second season ninety-seven per cent, of the caterpillars were destroyed
THE STRUGGLE FOR LIFE
219
by parasitic insects. This is only one of the many re- corded instances.
Social Organization. — We have already observed that insects qualified to conduct their affairs in colonies and societies are eminently successful. This congregating together is not confined to adults. Certain caterpillars possessing the property of emitting nauseous odors are iiTcuarious. The meaning of this habit seems evident:
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when many individuals emit this offensive odor at the same time, they become enveloped in an atmosphere which effectively serves to repel attack.
Feigning Death. — Motionless objects attract notice less readily than moving objects. Upon the slightest dis- turbance snme insects and many caterpillars become inactive, and for a time remain motionless. In the case of the attack of another insect with motives of conquest rather than an appetite to satisfy, this inactivity may allay further antagonism.
How can we account for the evolution or development of these various traits? We have observed that no two individuals arc identical, and that variation in struc- ture and habits exists. Under "Artificial Selection" our attention is called to the fact that under the intelli- gent selection of man these variations can be perpet- uated and become more marked. It remains for us to see if some such selection of forms can be found in nature, a selection which by unions strengthens pro- pitious variations or traits.
Artificial Selection.— - The character of our domestic animals is largely due to the intelligent selection exer- cised by man. We have the sagacious shepherd dog, the bloodhound with wonderful keenness of scent, the
220
ELEMENTARY STUDIES IN INSECT LIFE
greyhound with weak powers of scent but keen-eyed and fleet-footed. All these have been evolved, under man's direction, from the progeny of the wolf. By artificial selection the many varieties of pigeons, such as the fantail, carriers, and pouters, have been produced from the wild dove of Europe. Every stock-breeder and poultry-fancier is familiar with these principles of arti- ficial selection. Those animals or birds which possess the desired qualities in the highest degree are retained for breeding, while the rougher, smaller and less desir- able stock is marketed. Artificial selection may do in a few generations what natural selection would do even- tually.
Natural Selection. — Let us see if it is possible to find similar selection in the natural course of animal life. We have seen that but a small percentage of insect life reaches maturity, due to the struggle for existence throughout nature. Those who do survive do so by reason of some individual peculiarities. These peculiar- ities seem to be favorable. These favorable peculiarities, characteristic of the survivors, are transmitted to their offspring. Since both parents are liable to possess these peculiarities, the offspring are liable to show the pe- culiarity in a more marked degree. And so it will continue with subsequent generations. Those with favorable variations or peculiarities are liable to live to perpetuate these traits ; these traits tend to become more marked with each generation. The tendency is for those having these favorable traits in a small degree to succumb without leaving progeny. The weaker wasp in its endeavors to capture a spider as provision for its young is more liable to succumb than the stronger.
THE STRUGGLE F(>K UKK
The more nauseous the caterpillars are to insect-eating animals, the less likely are they to be molested. Thus, Nature is herself making selections. The tendency of this struggle and of this selection by nature is to re- tain an equilibrium, a balance of forces.. Under con- ditions that remain unchanged from year to year and century to century, it is possible for species to adapt their habits and instincts to their surroundings. But under changing conditions, such as we know have taken place in climatic conditions and in land and water areas, species must adapt themselves, must become mod- ified to these altered conditions, or cease to exist. The tendencies of this selection brought about by the strug- gle of life seem to be to bring to perfection all forms engaged in the struggle.
PART II
METHODS AND APPARATUS.— STRUCTURE AND CLAS- SIFICATION OF INSECTS
CHAPTER I
ACQUISITION AND PRESERVATION OF INSECT FORMS
IF there is one thing above another which commends the study of insect life in the secondary schools, it is the
«/ •
comparative ease with which the biological material can be procured. The study of Zoology is essentially a study of things, not books. And these things must be in the student's hands. Books furnish suggestions for study; they call attention to points liable to be over- looked by the untrained eye. In order that the practi- cal as well as the highest educational value can lie attained, the forms must unquestionably be placed in the hands of the student.
The teacher, situated far inland, who places stress and long study upon marine forms, unless well supplied with material, overlooks the most important element in Natural History instruction. The student needs to know not only the component parts of the form under consideration, but the reasons for the existence of these conditions. True, he may be told them. This makes little impression. With how much more force will the lesson come to him if he is enabled to see with his own eyes that the colors of the grasshopper harmonize with its natural surroundings; that the cloak of the pupa
has a capacity to resemble in color its support ; that
(222)
ACQUISITION AND PRESERVATION
223
the pronuba moth docs collect the yucca pollen and place it in the stigmatic chamber, and that it. has organs, belonging to no other insect of the order, pe- culiarly developed for the purpose, — than if he reads or is simply told that some of the organs of fishes which dwell at great depths in the sea, being adapted to sus- taining great pressure, burst when brought to the surface-water; that the angler, which dwells at great depths, bears on the tip of the dorsal spine overhanging its head a phosphorescent light that attracts small fish, upon which the angler feeds.
MATERIALS FOR FIELD COLLECTING.
The inland teacher has a wealth of material right at hand, easily obtained and as easily prepared. The tools required for collecting are: a net, cyanide bottle, vials for preserving, alcohol TO^f, formalin solution 2c/o.
How to Make a Net. - - The frame of the net is made of a circle of wire, in size about NV>. s. The circle is twelve inches in diameter; the ends of the wire circle are bent out, and are then soldered into a thin thimble five inches long. This part of the net had best be made by a tinner, and the cost of the same should be but a few cents. An empty fifty-pound flour-sack, thoroughly washed and bleached to remove the starch, may then be fastened to this rim. The rim of the net coming in contact with bushes wears out quickly, and therefore a binding of heavy material is placed there to give extra durability to the net. The thimble should not be over an inch in diameter. Fit into the end of this thimble a broom-stick about three feet long, and the net is ready for use.
224
ELEMENTARY STUDIES IN INSECT LIFE
FIG. 182. Net and hoop.
Another Way to Make a Net — The bag of the net may be made of almost any light-weight material ; cheese- cloth, mosquito netting or bobbinet are among the mate- rials used. For nets to be used both in capturing insects
FJld. of c/oH,
S:
of
FIG. 183.
on the wing and for sweeping the grass, a firm quality of cheese-cloth answers very well. The cloth should be as wide as the circumference of the wire hoop. The
.\<'<,>risiTION AND PRESERVATION
hoop is first wound with a narrow strip of the goods, to prevent the wire from wearing- on the cloth. The bag should he two-and-a-quarter times as deep as the diam- eter of the hoop.
Two bag's may be cut from one width of cloth, if properly managed. The cloth is folded lengthwise; the dotted lines in the accompanying figure show how to cut the net. The seams are then sewed up, and the wide upper part folded over the hoop and stitched down. It is necessary to make the upper part of the same width, in order to prevent its drawing in and decreas- ing the diameter of the opening; so we have shown in the figure a straight cut of two and one-half inches at the mouth of the net.
It is well to protect the covering of the hoop by a strip of heavy muslin sewed over it, since the rubbing of leaves and stems soon wears out the cloth around the
wire.
Preserving Materials. — Insects can be preserved in two
W7ays : by placing on pins, or in preserving-fluid, de- pending upon the character of the insect or the purposes to which it is to be put, If the insect is of delicate tex- ture, such as a larva or a nymph, it will shrivel if pinned. Such should be placed in 70% of alcohol or in a two-per-cent. solution of formalin. Insects col- lected for the purpose of dissection should be similarly treated, since the tissues remain soft and are easily worked. In the case of insects for immediate use in dissection, these can be killed in W% solution of chloral hydrate.
A cigar-box, the bottom being lined with corn or elder —15
226 ELEMENTARY STUDIES IN INSECT LIFE
pith, or cork, a strap fastened around three sides, then long enough to go over the shoulder, should be taken on every collecting trip. Several sizes of pins should be taken in separate vials, a killing-fluid, such as chloro- form or gasoline, in another bottle. Then, when such insects as butterflies, which would be destroyed by rub- bing among other insects in the cyanide bottle, are taken, these can be killed while still in the net by pour- ing a little of the killing-fluid over them. In this way they can be removed from the net without danger of escape. The proper-sized pin can be placed through the thorax and the insect pinned in the cigar-box, to be removed and spread upon return to the laboratory. With these simple and easily procured equipments, added to a pair of keen eyes, we are ready for the acquisition of material for our field study.
Field Collecting. — Many devices are used to lure and trap insects. Brief mention only will be made of such devices, since the student will gain his greatest knowl- edge of the habits of insects by collecting them in their native haunts. The careful student can soon learn to know for himself where certain classes of insect life abound; what life is confined to the forest, to the orchard, the meadow, and the open pasture; what classes live in the running streams and what ones live in the quiet pools.
The foregoing chapters have had something to say about the habitat of certain prominent insects. It is taken for granted that the first collecting will be for land collecting. The grass contains many forms which live near the ground. By sweeping the net back and forth in front of you, many of these will be captured.
ACQUISITION AND PRESERVATION 227
Tree and bush life, insects which live upon foliage, can be procured in the same way by sweeping the leaves of the trees and shrubs. Kocks, logs, and piles of leaves are the habitations of certain forms. Overturn such abodes of insects and see what ones live there.
Young collectors are apt to overlook certain forms to which great importance must be attached. Galls in weeds, upon leaves, and twigs of trees are readily ob- served and easily taken. Every one who has carefully observed the golden-rod stalk in the early spring is aware of spherical enlargements upon the stalk. Col- lect a number of these in the early spring, place them under a glass tumbler, and watch them from day to day. You will soon have ascertained the cause of the swelling. Then, caterpillars must not be overlooked. They represent developing life. The changes taking- place in such forms are fraught with interest. Place some of each species in alcohol or formalin, and bring the others to the laboratory to be reared. Water life teems with interesting forms. In ponds and sluggish streams, where vegetation fringes the shores, with a common garden rake immature insects and indeed some fully developed insects can be brought to shore.
Note-Book. — Many insects spend much of their lives skimming over the water, and others live upon the vegetation growing out of the water. And so, in col- lecting, the acquisition of materials is but one of the considerations. The blank book for field-notes should be a record of every insect taken. The geographic location should be noted.
The notes upon insects taken should give the day and year, time of day, kind of d;iy.--hot or cold, clear or
228
ELEMENTARY STUDIES IN INSECT LIFE
cloudy. The weather influences insect life very per- ceptibly. The character of the insect's surroundings - that is, taken under stones or logs, or feeding upon certain plants --is also of importance. When insects are found on plants or trees, an opportunity is afforded the student to acquaint himself further with the flora of his vicinity.
This point of the food plants of insects is a very important one, especially in the collection of scale in- sects and plant-lice.
Map of the Vicinity. — Every student should be pro- vided with a map of the vicinity of his school. This map should show the section lines, all streams of any importance, ranges of hills, and places of historic inter- est. An idea of the scope of such a map is shown in the illustration. By referring to this the student can trace his various collecting trips and locate the exact position of his captures.
Manner of Keeping Records. — What is the most con- venient way to keep these notes? Simply place on the pin beneath the insect a very small card bearing a number, which might be called the accession number; that is, the specimen can be numbered beginning with 1, and going on, — no two insects bearing the same number, unless they happen to be of the same species, taken at the same time and under like conditions. A corresponding number is entered in the field-book, and opposite this number are recorded the notes and obser- vations upon the insect. Remarks may be added upon the habits of the insect observed ; whether active or sluggish; resemblances to the surroundings; attempts at defense; and other points which suggest themselves
ACQUISITION AN1> i'K KSKKVATION
FIG. 184. Map of collecting vlcluity. An aid In note-taking.
230 ELEMENTARY STUDIES IN INSECT LIFE
at the time of note-taking. These notes should be written in the field while the collecting is going on. Observations should always be written at the time they are made.
Collecting at Lights. — Insects can be collected at elec- tric lights ; but in the collecting nothing more is ac- complished than the acquisition, of the things, and the knowledge that such insects are attracted to lights.
" Sugaring."- - Many moths and some other insects are to be brought to notice by a process termed ''sugar- ing." This consists of placing, before dark, on trunks of trees, fences and similar objects, a paste of sugar and water. Dark-brown sugar is preferable. The paste should be of proper consistency to apply with a brush, but not so thin that it will flow from the object to which it is applied. Cover a space about three inches wide and several inches long on the trees and fence-posts. Do this about sunset. Return after dark with a common lantern in hand, and take such insects as are found feeding upon this sugar paste, 'by placing the cyanide bottle over each one. Since there may be many insects at the sugar, it is well to lie provided with a. number of wide-mouthed cyanide bottles. By this method of sugaring some species of moths can be taken, species which are rarely seen under any other condition.
Preservation of Insects. — For reasons already given, those insects which are to lie placed in preserving-fluids will need no other attention, unless the fluids become discolored, — then a change of fluid is necessary. A small card bearing the lot number, the writing being made with carbon pencil, should be placed in the bottle with the specimen. Labels pasted on the outside fre-
ACQUISITION AND PRESERVATION
231
quently become detached. Remember, that specimens without adequate data, such as covered in the points mentioned, are practically worthless for cabinet use.
Insect-pins are a kind of pins made especially for the purpose. The kinds much used are Klaeger numbers 2, 3, 4, 5, length l£, and Carlsbader numbers 2, 3, 4, 5, length H inches. These pins are numbered accord- ing to their fineness from 00 (the finest in the trade) to 10 (the coarsest). The finer pins are difficult to handle. It will be more convenient for the beginner to mount small insects on points or angles to be described later.
Upon returning from a collecting trip, the insects should be removed from the cyanide bottles, provided all have been at least one-half hour therein. From cyanide bottles place upon dry blotting-paper, and re- move all foreign particles with a soft, dry brush. All specimens should be mounted before they become dry and brittle.
Insects should be pinned through the middle of the thorax (mesothorax) when this, as is generally the case, is well developed. Coleoptera, however, should In- pinned through the right wing-cover, since if the pin is passed down between the wing-covers these will spread apart. Hemiptera should be pinned down through the triangular piece behind the thorax. This piece is called the scutel.
The pin should always project about one-half inch above the insect, to facilitate handling. To insure evenness in this regard, a small piece of cork inserted one-half inch in a piece of small glass tubing can be used as a gauge. This can be passed over the head of
232
ELEMENTARY STUDIES IN INSECT LIFE
the pin, and the pin or insect, as the case may be, pushed down until the length of the pin above the body of the insect equals the distance the cork is inserted in the glass tube. Small insects can be pinned by placing on cork or pith and held between fingers or forceps. Insects too small to be mounted in this way can be gummed with any good quality of glue to card-points
previously placed the proper dis- tance upon pins. These points can be cut with a pair of scissors, from cardboard. Clip diagonally across a strip about a half-inch wide, plac- ing the scissors about one-eighth of an inch from the end of the strip. Do not make the tip pointed, but blunt. The next cut, made straight across the strip, will give the second cardboard triangle, and so on. Place pins through the wide end of the card triangle, a little glue at the apex. Place the insect on across the tip of the card. The glass tube-gauge can be used to locate properly the distance of the card from the top of the pin. Small flies and small lepidoptera are best mounted on fine pin-points located in small oblong pieces of cork or pith. This oblong piece, like the card triangle, is supported at the proper distance from the head of an insect-pin of suitable size. Insects with long bodies, such as dragon-flies and walking-sticks, some- times require a narrow strip of cardboard pinned be- neath them, or a fine wire passed through the body, as
a. b.
FIB. 185. a, insect glued on card-point ; b, insect mounted on fine pin-point.
ACQUISITION AND PRESERVATION
233
a support for the long- abdomen. Insects when pinned should be put in a safe place to dry, where they are not liable to be broken and where mice cannot get at them; for mice consider insects, even dry ones, tidbits.
Lepidoptera, and other insects with broad and flat- tened wings, should have their wings spread. This can be accomplished with the aid of a spreading-board. This board is made of two pieces of thin pine boards laid parallel and fastened by braces at the ends, and if the boards are long there should be a center brace. There should be enough space between the boards to admit the bodies of the insects to be spread. This space
FIG. 186. Spreading-board for Lepidoptera.
between the boards should be covered from beneath with sheet cork or corn pith, to hold the pin upon which the insect to be spread is mounted. The braces should be high enough to allow the pins holding the insect to pass through without touching the supporting-table. To spread the insect, first pin through the rnesothorax, then place firmly in spreading-board, by the pin pass- ing through the cork or pith. Pin with common domes- tic pins a narrow strip of paper across the base of the wings, the pins being fastened a little in advance and be-
234
ELEMENTAKY STUDIES IN INSECT LIFE
liind the wing-margins. Use one of tlie dissecting-needles (page 252) to move the wings forward into position. This needle should be placed behind one of the strong nerves of the wing, to prevent tearing the membrane. When the wings are in proper position, tighten the basal strips and place another (somewhat wider) strip across the outer half of each of the wings. Fasten with domestic pins in the same manner as the basal strip was fastened.
Cabinets.— -Insect-cases are of many devices. Each is suited to its purpose. The high-school collection should be placed in a cabinet that has been erected for the purpose, one that will insure the safety of the collec- tions, and one easy of access for reference and study.
One of the prerequisites of a museum case is, that it be so constructed as to make it practically impossible for museum pests, other insects which live upon dried in- sects and other museum collections, to gain entrance. Chief among these pests are the little beetles of the buffalo-moth family. Frames can be made of soft-pine strips, one-half inch thick, to tit AVI thin the case. These frames are covered above and beloAV Avith a heavy qual- ity of good Avhite paper, pasted to the strips. This paper frame is dropped Avithin the case, and serves to hold the insect-pins in place. The insects can be ar- ranged in roAvs, Avith labels on the left of each series. Four specimens of a kind constitute a series.
A handy case is one the size of which is in inches 10x14x5 (outside measurement). This case consists of two parts of equal size, each being 2^ inches deep. The corners are dovetailed. On the inside of one of the com- partments a strip extends from the bottom on each side
ACQUISITION AND PKKSKKYATION"
235
up above the box itself about three-quarters of an inch. This is to insure a closed joint when the box is closed. The compartments* are fastened together on one side1 with suitable hinges, and on the other, when closed, with a hook.
The wood in this case should be of some non-resinous kind. Cardboard pasted on light wooden frames made
FIG. 187. A student's cabinet.
to lie within the case fastened in the bottom of each compartment will serve as a receptacle for the pins of mounted insects. For this case, boards one-half inch thick are the proper size. This student case will hold insects in each half, and can be placed on a shelf, up- right, in a position similar to a book on a shelf.
Arrangement of Insects. — It will be found convenient to fill all cases with insects of the same order. Within the order arrange the specimens under suborders, fam- ilies, genera, and species. For the arrangement and
236 ELEMKXTAKY STUDIES IX IXSKCT LIFE
study of insects, several sheets of cork or large blocks to which a layer of corn pith has been glued will prove valuable. These will hold the specimens while being mounted, transferred, or studied.
Relaxing Insects.— -Frequently it is desired to spread or pin insects which are rigid. These can be relaxed. A vessel half filled with sand saturated with water, then closely covered, will furnish a moist chamber. In this upon heavy blotting-paper place the insects to be re- laxed. Allow to remain from one to three days. They must not remain too long, else mold will destroy them. A few drops of carbolic acid will retard the growth of mold. When the insects have become relaxed they can be handled as readily as when captured.
Mailing Insects. — Students, too, will frequently find it desirable to mail insects in exchange for others, or in order to secure proper identification. This is fre- quently done. Many exchanges are conducted by mail, and many insects are sent to proper authorities for de- termination. Pinned insects must be firmly pinned in a box having a sheet of cork securely fastened to the bottom. The box must be tightly covered and wrapped loosely, first with cotton and then with excelsior. A heavy paper should cover all. The excelsior and cotton are to modify the jars and shocks which the package will receive in transit. Specimens in preserving-fluid can be mailed in a regular mailing-case made for the purpose. A cylindrical piece of soft wood can be bored out to accommodate a fair-sized vial well wrapped in cotton. This closed with cork of required size, serves the pur- pose very well.
Various means and devices will occur to the ingen-
AM) I'KKSKUVATIOISr
237
ions student in his studies, and sneh when perfected will be valuable.
Dealers in entomological supplies, from which such as forceps, pins, sheet cork, etc., can be obtained :
The Bausch & Lomb Optical Company, 513-543 N. St. Paul street, Rochester, N. Y.
John Akhurst, 78 Ashland Place, Brooklyn, N. Y.
M. Abbott Frazar, 93 Sudbury street, Boston, Mass.
Entomological Society of Ontario, Victoria Hall, London, Ontario.
(Jueen & Co., 1010 Chestnut street, Philadelphia, Pa.
Charles C. Riedy, 532 Montgomery street, San Francisco, Calif.
Dealers in optical instruments, from whom lenses, microscopes, etc., can be obtained:
The Bausch & Lomb Optical Company, New York and Roch- ester, N. Y.
Eimer & Amend, 205-211 Third avenue, New York city.
(jueen & Co., 1010 Chestnut street, Philadelphia, Pa.
The Franklin Educational Company, Harcourt street, Bos- ton, Mass.
William Krafft, 411 W. Fifty-ninth street, New York city.
Spencer Lens Company, 546 Main street, Buffalo, N. Y.
REFERENCE BOOK.
Directions for Collecting and Preserving Insects, C. V. Riley. Smithsonian Institution, Washington, D. C., 1892. Price, 25 cents.
238 ELEMENTARY STUDIES IN INSECT LIFE
CHAPTER II
INCOMPLETE METAMORPHOSIS
THE GRASSHOPPER
THE materials required for the study of the develop- ment and habits of the grasshopper are simple and within the possibilities of anyone: a breeding-cage, a pair of sharp eyes, a hand-lens, and an insect net.
The breeding-cage can be very simply made by cover- ing with wire netting an open space left on each side of a good-sized store-box, and placing a quantity of sand in the bottom of the box. This should be placed where a moderate amount of sunlight will reach it during a part of the day. Young grasshoppers arc tin- ones to be desired, and these can be recognized by the absence of wings, and the presence of wing-pads in- stead. In the very first stages of the grasshopper's life even these wing-pads are absent. Many of these young grasshoppers may be taken without the aid of a net.
A net will facilitate the work greatly, and will also be required in other branches of the study. (See page 224 for directions for making net.)
A good hand-lens can be procured from the jeweler or from some optical firm. ( See page 2:)7 for addresses of firms.) Of the lenses more moderate in price, the one known as the Coddington is the best. In buying a lens it will be well to purchase one that will work upon the home-made dissecting microscope described on page 251.
METAMORPHOSIS
239
Acquisition of Material — The breeding-cage well made, equipped and in position, the hand-lens and net as ac- companiments for your bright eyes, you are ready to seek young grasshoppers along the roadside, or in the meadows or cultivated fields. Young grasshoppers may be found at any time of the year, but are most common in the early spring. They can be best taken in growing vegetation, such as meadows and pasture-lands, by sweep- ing, and along the roadsides by dropping the net over them. As a means for carrying them from the field to your breeding-cage a pasteboard shoe-box with a V- shaped trap-door cut in the lid is a handy appliance. It is simple, and a very effective means of transportation. When the grasshopper is caught, the apex of the trap- dour is pushed down witli the finger and the insect dropped in. The pasteboard has enough spring in itself to close the opening.
Care of Breeding-Cages.— Grasshoppers are not at all delicate in their tastes, and will adapt themselves greatly to existing circumstances. They prefer, however, the cultivated grasses, cereals, and clover. They also eat readily the leaves of young shoots of peach trees. A number of weeds which grow upon cultivated land are also readily partaken of by these insects; the petals of the opening flowers of the com- mon sunflower are not objected to as a diet by some species of grasshopper.
Great care and attention should be given to the breeding-cage, and all dry vegetation and grass should be removed daily. It is well, however, to keep in the ca^e all the time a few long stalks of weeds or other vegeta-
240 ELEMENTARY STUDIES IN INSECT LIFE
tion, for the nymphs to ascend and cling to while molt- ing.
Some Points for Observation.— - The time of appearance of wing-pads ; the time of day when the molt takes place ; the color-markings of the insect hef ore molting and after molting ; the number of molts ; date of maturity ; relative positions of the narrow wing-pad and the wide wing-pad in the nymph, and of the nar- row \viiiiis (the tegmina) and of the wings in the adult; time, manner and place of ovi position. As the work de- velops the student will find main- other interesting facts to increase the volume of his notes.
THE DRAGON-PLY
The study of tin- development and growth of the grasshopper familiarizes us with the incomplete meta- morphosis of an insect which passes its whole life on land. jVlany insects spend a part of their existence in the water. The dragon-flies are insects with incomplete metamorphosis.
To rear these insects is not a difficult task. In the rearing many delightful as well as instructive observa- tions will be made. The first thing to do is to obtain the insects. Each group of dragon-flies has its own peculiar place. The nymphs — and it is these we will seek to find --of one division (Gomphince) live in the sediment at the bottom of pools, frequently pools with little or no vegetation on the bottom. Two other di- visions (Agrioiiintt' and Arxclniiiiw} are to be found among submerged vegetation.
Since all of these live for a considerable length of time in the water, permanent pools and streams will
METAMORPHOSIS 241
be the places to look for them. In the early spring they can be drawn ashore with a garden-rake; Inter in the season a water-net, one with coarse cloth to allow the water to pass freely through, must be used. In the summer-time the vegetation would interfere with the working of the rake. They will make their presence known bv endeavoring to extricate themselves from the
»j CJ
rakings. Such as are taken can be placed in a bucket of water, to be carried home in safety. A water-pail, half-full of water, with a few twigs or sticks extending well above the surface of the water, is the kind of place to keep these nymphs. The bucket should be covered with mosquito netting, to prevent the escape of any which may emerge. A good meal of mosquito larva? (wigglers) once or twice a week will keep these nymphs thriving. The bucket should be kept out- doors, where the nymphs can get the benefit of the sunlight.
In collecting it will be well to chose only the oldest nymphs for that season's study. The older ones have longer wing-pads, which extend to about the middle of the abdomen. These will emerge during the same season.
The points for the student to observe are:
Method of feeding. For the purpose of answering this question, several can be fed in a glass vessel filled with water.
Time of day of emergence.
Actions during transformation to adult. I^ote es- pecially the color of the insect just free from the nymphal case, and the characteristic colors as they appear. -16
242
KI-KMK. \TAUY STl'DIKS 1 .N INSECT I, IKK
These observations should be carefully written clown, preceded by the field-notes. The field-notes should state the location where taken, the character of the water and vegetation, and the abundance or scarcity of the nymphs.
COMPLETE METAMORPHOSIS
SWALLOWTAIL BUTTERFLY
In the consideration of the black swallowtail butterfly, several questions have been left to be answered, and it is to be expected that other queries will arise in pursuit of answers to:
How many times does the caterpillar molt ?
How manv broods of butterflies come forth in your
«/ i/
locality during the summer season ?
In what positions, besides the one given, do you find the eggs ?
Place one of the caterpillars upon a pane of glass on the window, and note how it endeavors to ascend the pane.
Nowhere within the realm of Xatural History are biologic studies more easily conducted, or the facts ac- quired more remarkable or interesting, than in the study of the fascinating phases relating to life history and habits. Investigations can be most practicably con- ducted by establishing these caterpillars in surroundings as nearly natural as possible, where they can be fre- quently observed, and at times constantly watched.
Points to be observed are: temperature, moisture, proper food, and right conditions for pupation.
Care of Larvae.— - The manner of caring for the larvae of the black swallowtail will apply to the rearing of
METAMORPHOSIS
243
other caterpillars. Caterpi liars should be taken with their food plant, the stein of plant placed in a bottle filled with moist sand, and this surrounded with soil in a flower-pot. In order to keep the larvae from roving, a number of devices can be used.
Breeding-Cage. — A larnp-chimney or lantern-globe with Swiss muslin tied over the top (Fig. 188) can be placed over the food plant, or where many larvae are
being studied, a box can be well used. The soil must contain about the same degree of moisture that shaded earth will contain ; it must not, be soaked, but can be kept moist, in the case of the flower-pot, by keep- ing water iu the saucer beneath the flower-pot. The earth in the screened box can be sprinkled lightly, but fre- quently enough to retain the right de- gree of moisture. Many larva."1 enter the ground to pupate. Should the soil be too moist the pupa will mold and die. Should it be too dry the insect will not develop properly.
A fresh supply of food should be furnished daily, and all litter removed from the breeding-cage. It will very often be found impracticable to remove a part of the old food when new food is introduced; since it is not best to disturb the caterpillar, but to wait until it has moved from the old food material to the new.
Records. — Always keep beside the breeding-cage pen- cil and note-paper, to make notes of every change just
FIG. 188. A conven- ient breeding-cage.
244 ELEMENTARY STUDIES IN INSECT LIFE
at the time when the observation is taken. At no other time can it he so well or so accurately described. In fact, every observation, both in the field and laboratory, date of capture, locality, food plant, and other points suggested at the time, should be carefully set down in the pocket note-book, and this together with the breed- ing-cage notes placed in ink in a larger record book for permanent reference. Every study undertaken .should be with a definite aim in view, and the habit should be early formed of making accurate observations. Should the note-taking and observations be dilatory, the prac- tical and educative results will, it must be emphasized, be of little or no value.
Care of Pupae. — When the larva* have pupated, the breeding-cage must be removed to the cellar or to some place where the temperature is uniform and moderate. Though extreme cold may be endured, sudden changes must be guarded against.
The Adult. — When after due care and watchfulness the mature insect has come forth as the reward, it may not be a butterfly, but a moth or a skipper. Compari- son with the antennae (Figs. 1G7, 168, 1C9) will in the majority of cases enable the observer to ascertain to which class the insect in hand belongs. Is there any difference between the pupa-case of a moth and the pupa- case of a butterfly ?
THE HOUSE-FLY OR BLUEBOTTLE-PLY
For the study of the life history of the fly, the blue- bottle-fly lends itself readily.
Egg. — The egg of the bluebottle-fly can be procured by exposing fresh meat for several days. In winter- time, warm days should be selected for the exposure.
METAMORPHOSIS
245
Larva. — When the eggs have hatched, the larva- may be reared upon bran. Note the changes during growth. Describe the process of pupation.
The Pupa. — What is its color ? Does the adult emerge through the side or the end of the pupa- case ? How does the
front of the head of the FIG 189 Foot of house.fly. Greatly newly emerged fly dif- enlarged.
fer from that of the same fly several hours later ? How is the opening in the pupa-case made?
Adult. — Place fly under a glass vessel (a plain, thin water-glass will do). Rest the inverted glass upon black paper on which a few grains of granulated sugar have been placed. ISTote the manner in which the fly feeds upon the sugar. Place within the glass vessel substances sweet and sour, neutral and of various colors, such as different colored sugar, salt, molasses, vinegar. What substances seem to attract the fly most ? What particular quality seems to form the greatest means of attraction ? AVhat senses seem to be relied upon in the discernment of these various substances?
COMPANION BOOKS.
A Manual for the Study of Insects, .1. H. and A. B. Corn- stock. Comstock Publishing Company. Ithaca, N. Y., 1895. Price, $3.75, net; postage, 34 cents.
The Life of a Butterfly, S. H. Scudder. Henry Holt & Com- pany. New York, 1893. Price, $1.25.
Everyday Butterflies, S. H. Scudder. Houghton, Mifflin & Company. Price, $2.
First Report of the U. S. Entomological Commission. ( This
246
ELEMENTARY STUDIES IN INSECT LIFE
deals at length with the Rocky Mountain Locust.) U. 8. De- partment of Agriculture, Washington, D. C.
Catalogue of the Odonata (Dragon-flies) of the vicinity of Philadelphia, with an introduction to the study of this group of insects, P. P. Calvert. Transactions Amer. Ent. Society, Phila- delphia. Price, $1.
The Natural History of Aquatic Insects, L. C. Mial. Macmil- lan & Co. London and New York, 1895. Price, $1.75.
On the Origin and Metamorphosis of Insects, J. Lubbock. Nature Series. Macmillan & Company. New York and Lon- don, 1895.
The Butterfly Book, W. J. Holland. Doubleday & McClure. New York, 1899. Price, $3.
Moths and Butterflies, Mary C. Dickinson. Ginn & Co. Boston.
Nature Study and Life, C. F. Hodges. Ginn & Co. Boston. Price, $1.75.
HABITS OF ANTS
247
CHAPTER IV
THE HABITS OF ANTS
ANTS can be readily studied in artificial homes. For this reason much will be expected from the in- vestigations of the student. The accompanying sketch shows a board with a trench, a moat, chiseled out around
FIG. 190. Board plan for an artificial ant-nest.
the outer half. This moat is one-half inch wide and one-half inch deep; it should be well painted, to pre- vent the escape of any water; then fill with water to keep the ants within bounds. A strip of wood should be nailed across each of the grain ends, to prevent the board from warping. Place in the center of this board a pane of glass ; surround the same with narrow strips of wood about an inch thick ; place on this glass several small narrow strips about the thickness of the ant's body ; these strips are to support another pane of glass equal in size with the first. Sprinkle a layer of sand
248 ELEMENTARY STUDIES IN INSECT LIFE
on the under glass, about the thickness of the thin strips of wood ; then break a corner off the upper glass and place it on the top of the layer of sand and strips.
Now yon are ready for the ants. The object, you see, is to have a place where the ants cannot get away, and yet where they can have some freedom and a home which will be open for your inspection. That they may live in the dark when not under observation, it will be necessary for you to cover this glass house with a board. The board can be lifted from time to time and the workings inside observed. You will readily see, also, that it will be necessary to have the right amount of earth or sand, else, if there is too much, the workings and tunnelings will be beneath the surface.
Ants are not hard to find under surface rocks, logs, and in old stumps. In quest of these, a garden trowel and covered tin bucket are the only things necessary. In collecting ants to establish in homes there is one form necessary - - that is the queen ant, easily recog- nized by her large size. When she is found it is a small matter to collect a number of workers, their eggs, larva? and pupa?. Place earth, rubbish and all, in your bucket, cover them and bring them to the artificial nest ; pour the whole mass on the upper pane of glass, remove the surface rubbish by degrees, and soon the ants will begin to work their way between the panes of glass through the broken corner which you have left as an opening for them.
Colonies inhabiting hollowr branches of sumac or elder are easily transferred. On one occasion a baking- powder can containing a hollow sumac knot, the home of a full colony of ants, was brought to the laboratory.
HABITS OF ANTS
249
It was late in the evening, so that no attempt was made to transfer the ants at that time. During the night the little workers had discovered a hole in the side of the can, previously stopped with a toothpick ; this they chewed away. When found in the morning they had taken themselves, their queen, their pupa1, eggs and larva1, and were comfortably established in a piece of glass tubing which chanced to be near by. Here, under cover of a pasteboard box, these ants were an interesting source of study and experimentation for the students until the summer vacation, six weeks later. They were country ants, and had to learn to like city ways. For instance, at first they ran around over granulated sugar, paying no attention to it; hut later, fed readily upon it. The experiments conducted with these ants you can likewise carry on.
»/
Ascertain what foods they will eat.
Remove several from the nest, and return them the next day.
Place near the entrance to the nest a few ants of the same species but from another nest, and note the result.
Study the action of the ants in their artificial nest, the character of the tunnelings they build, how they treat the young, the larva?, the pupa1, and the queen.
Secure a copy of "Ants, Bees, and Wasps," by Sir John Lubbock, the reading of which will suggest many valuable experiments upon the actions and instincts of this very colony of ants which you have established.
250
ELEMENTARY STUDIES IN INSECT LIFE
CHAPTEE V FORM AND FUNCTION
HEIST the study of Physiology is under way, comparative anatomy lends in- terest and adds value to the instruc- tion. The material may be procured easily, and the few facilities required for bringing the subject-matter intel- ligently before the class favor an anatomical study of the skeleton or external anatomy of the grasshopper. The skeleton of the grasshopper,1 the history of which we have already studied, will be the subject considered. A word in beginning concerning skeletons. As every student of physiology is taught, skeletons are of two kinds: endo-skeletons, or skeletons within the body and surrounded by muscles; exo-skeletons, or those without the body, having all muscles on the interior. The skele- tal structure of man comes under the first class ; the rigid outer structure of insects under the second class. Every one who has studied human physiology remem- bers among the first topics to be found in the text is 1 Uses of the Skeleton," and in answer to the question, " What are the uses of the skeleton ? " if he were per- mitted to use another's language instead of his own he would say, " To give form to the body, to protect the delicate organs, to furnish attachments for the mus- cles, to serve as levers for locomotion." And when an
^Melanoplus differentialis.
FOKM AND FUNCTION
251
apt student takes up the study of the skeleton of the grasshopper he will readily see that its skeleton serves identically the same purpose as the human skeleton. The integral parts of the human skeleton we call bones; the separate portions of the insect skeleton we term sclerites. That constituent which gives bones their firm- ness we commonly speak of as lime; that which lends rigor to the sclerite is called cliitine.
An examination of the body-wall of an insect shows it to be composed of a number of distinct pieces or sclerites. The lines separating these pieces are known as sutures. Sutures here, just as in the anatomy of the human skele- ton, are not freely movable joints. That term is re- served for those articulations which are freely movable ; for example, joints of the locust's leg.
FIG. 191. Plan for simple microscope stand.
Aids in the Laboratory. — In addition to the appliances, net and lens, already mentioned, the following simply constructed materials will be of assistance :
It will at times be found advantageous to have the specimens stationary, in order that the parts being stud- ied can be manipulated under the lens. For this pur- pose, Figure 191 shows a simple dissecting microscope stand, made from a 4 x 4-inch pine block nine inches
252 ELEMENTARY STUDIES IN INSECT LIFE
long, with two corners beveled in accordance with dimen- sions marked in the figure. On the side, at the middle of the four-inch table, a metal post about one-fourth inch in diameter is set in the block, and extends four inches above the table. Around this post one end of a wire sufficiently heavy to hold the weight of the lens is wrapped three or four times ; the other end is made into a loop, to hold the lens. The coil on the post will slide up and down, enabling the operator to focus the lens. In some cases a small square of glass fastened on the dissecting-table will be found helpful. This enables the needles to cut more accurately. When the specimen is to be held in a stationary position, fasten to the table a slice from a large cork, or a small slip of .soft wood, then pin to this the insect in the position desired.
Dissecting-needles can be made by driving the head of a sewing-needle into a wooden penholder or stick of similar size. Two of these needles will be required.
Two grades of pencil will be required, a soft pencil and a hard pencil.
The main qualification in a note-book is the paper. This should be white, of good weight, unruled, and well finished. These note-books can be made. The paper of the desired quality, high-grade flat cap of proper weight, for example, can be purchased and cut into pages about 8^ by 6| inches. These can be kept in an old book cover, or heavy cardboard cover. When a drawing has been satisfactorily finished on a sheet, the sheet, accom- panied by its notes, can be laid aside in serial order. It will be found advisable to make each drawing large and distinct. It is advisable to place only one drawing upon a page. Should more than one drawing appear
FORM AND FUNCTION
253
upon the same page, the possibility for confused im- pressions arises.
Preparation of Specimen. — The most humane and at the same time the most convenient way to prepare the live specimens for anatomical study is to place them for from one-half to three-quarters of an hour in a cyanide bottle. Any wide-mouthed bottle will do. Cnt a piece of cyanide of potassium,1 the size of a walnut, into small pieces, place in the bottle and cover with plaster of
-
FIG. 192. Cyanide bottle.
paris, add enough water to moisten the plaster of paris, allow to stand uncovered until dry ; then put a circular piece of blotting-paper which will cover this plaster formation in the bottom of the bottle. This paper will keep the insect dry, and when the blotter becomes very moist it should be replaced by another. A roll of blotting-paper is frequently placed around the inside of
1 Cyanide of potassium is a deadly poison. Great care should be exercised while handling it, to avoid inhaling the fumes or bringing the substance in contact with the mouth.
254 ELEMENTARY STUDIES IN INSECT LIFE
the bottle, to aid further in taking up the moisture which collects therein.
Terms Used in Denning Position and Direction. — With a specimen of the yellow grasshopper in hand it will be evident to the observer that the terms " up " and " down," " before " and " behind," and kindred terms denoting direction, are frequently indefinite in describ- ing the location of the parts of an insect. Should these terms be applied to an insect, the body being so small and its position so easily changed, it is evident that some confusion and frequent ambiguity would be likely to attend.
In locating and describing parts, not only in the study of insect life but also in other branches of Zoology, a series of terms adapted to the requirements have come into use. These the student will do well to understand fully in application and significance.
The cephalic direction is headward. This does not necessarily refer to the head, but refers to anything ex- tending in the direction of the head ; for instance, in Figuie 202 the front margin of the wing will be spoken of as the cephalic margin of the wing. The adverb de- noting direction headward is ceplialad; that is, one can say the front wing is ceplialad of the hind wing.
The direction opposite from cephalic is the caudal di- rection, or tailward, and is used in just the same way as the term cephalic direction. The adverb from this is caudad.
Lateral directions refer to points on the right or left side of the body. Laterad is the adverbial expression used.
The ventral direction, or downward, refers to what
AND FUNCTION'
255
might be spoken of as the under side of the insect,— that part of the body which lies nearest the ground. The adverb is ventrad, and is used as in the preceding.
The other direction would necessarily have reference to the back of the insect, and dorsal direction is the term used here, and dorsad is the adverb.
Now, in order that you may understand the applica- tion of these terms, refer to Figure 202, and notice that the two wings extend laterad from the body, and that the antenna is cephalad of the base of the wing, and like- wise that the wing is caudad from the antenna. The utility and application of these terms will be more read- ily understood with the specimen in hand and the ana- tomical study in progress.
EXTERNAL DIVISIONS OF THE BODY.
An examination of the whole body will readily show three divisions: the head, the thorax, and the abdomen.
The Head, apparently one piece, contains the mouth, eyes, and the long thread-like appendages known as the antennae.
The Thorax is in the central part of the body, furnish- ing attachment for the wings and legs.
The Abdomen is a slender portion extending caudad
from the thorax.
TITE HEAD.
Fixed Parts of the Head.
Compound Eyes. — (Fig. 193, J5) Prominently situated upon the lateral portions of the dorsal half of the head are the two prominent compound eyes. The hand-lens will reveal the honeycomb or network structure upon the surface of these eyes. If a compound microscope is at
256
ELEMENTARY STUDIES
INSECT LIFE
hand, cut off one of the eyes, wash well in water, and place the head covering under the microscope, using a low-power lens, Note the hexagonal divisions of the eye.
Each of these divisions con- stitutes the cornea for a sim- ple eye. There being many of these in each of the eyes as seen externally, it is emi- nently proper to call them compound eyes. Each of the simple eyes of which they are composed is termed ocellus (plural, ocelli).
Simple Eyes. — Between the compound eyes in the front part oi the face are located three bright, shining spots. One can be found immedi- ately in front of the upper half of each compound eye, and one between the antennal
sockets. These are the simple eyes. (Fig. 193, l>, 1), l>.} Epicranium. — The epicranium is that part of the cra- nial box which surrounds and holds the compound eyes and the simple eyes, and extends down the face to a dis- tinctly marked transverse line. The epicranium is di- vided into three parts.
Front.— - The front is that part which is on the cephalic aspect of the head.
Gense.— -The lateral portions of the epicranium are called the gense, or cheeks.
FIG. 193. Front view of head with clypeus and labrum removed to show mandibles in position, a, antenna ; 6, ocelli ; B, compound eye ; C, mandible ; d, maxilla ; e, maxillary palpus ; /, labium ; g, la- bial palpus. Enlarged about five times.
FOKM AND FUNCTION
257
Vertex.— - That portion of the epicranium which lies on the top or dorsal aspect of the head is known as the vertex.
Clypeus. — Just helow or ventrad of the front of the epicranium is the transverse suture, pre- viously mentioned, that separates the front of the epicranium from the broad, rather short sclerite. This sclerite is the clypeus. (Fig-. 1.94.)
' ' , r , V, . ,. , , , . FIG. 194. Clypeus
Make a drawing ol the cephalic and labrum. En. aspect of tlie head (that part of the lar^ed about five
times.
head which extends directly forward, and which might be commonly spoken of as the front view of the head), showing and naming all the fixed parts. In making these drawings the greatest care should be given to the accurate delineation and proper proportions of the parts, without any attempt whatever being made at shading1. In the majority of cases shad- ing will only tend to mask the details which must neces- sarily be brought out. The accompanying illustrations are given simply as aids, and not with the intention that any attempt whatever shall be made at their repro- duction. The line-drawings will have a very different appearance from shaded illustrations, and will go much farther toward cultivating the powers of observation in the student.
Movable Parts of the Head.
Antennae — (singular antenna) (Fig. 194, a}. — Just between the compound eyes arise the two many-jointed antenme. Make a drawing of these antennae, showing
the number of joints. —17
258
ELEMENTARY STUDIES IN INSECT LIFE
Mouth-parts. — Taken collectively, all the organs which aid in the mastication of food are called the month-parts.
Labrum. — The freely movable flap which is joined to the ventral margin of the clypens is called the labrum, or npper lip. (Fig. 19-1.)
Mandibles.- • By removing the labriim and clypens the mandibles become visible. (Figs. 193, <-, 195, c.} Note
FIG. 196. Inner view of maxilla, ic, lacinia ; glt
FIG. 195. Front view of head, galea . p^ palpus ; m, mem-
with mandibles spread out. c, brane. Enlarged about five
mandible ; <i, maxilla ; e, maxil- times,
lary palpus ; /, labiuni ; gr, labial palpus ; //, hypopharynx. En- larged about uve times.
the direction of motion in the act of chewing. Remove one of the mandibles, and carefully draw it.
Maxillae. — (Fig. 195, rf.) After removing the mandi- bles there appears another pair of jaws, the under jaws or maxilla?. These are more complicated organs, and need to be removed with some care. If the head has not been removed from the body before this time, remove it now and pin it with the back or caudal aspect uppermost to a piece of soft wood or cork. Lift off the freely movable flap, the labinm, of which we will speak later. (Fig.
FORM" -VXD FUNCTION
259
107.) The labium removed, carefully pry apart the two maxillae, endeavoring to obtain the full basal portion. With the aid of a small hand-lens, the following parts may be made out :
Lacinia. — A curved and toothed part, somewhat like the mandibles. (Fig. 169, Le.)
Galea. — Lying laterad or outside of the lacinia is the spoon-shaped galea. The galea is composed of two seg- ments. (Fig. 196, gl.Y
Palpus. — Arising from the basis of the galea is the long five-jointed palpus, or feeler. (Fig. 196, p.}
Make a drawing of the rear or caudal view of the maxilla1, naming all the parts.
Labium. — With the aid of a hand-lens, the labium may be analyzed into the following- parts :
The two movable flaps, ligula. (Fig. 197, L.)
The central portion, known as the mentum. (Fig. 197, If.)
Arising from the basal por- tion of the mentum are the labial palpi. (Fig. 197, Lp.)
Articulating with the base
FIG. 197. Labium. g, gula ; S, submentum ; M, mentum ; Pg, palpiger ; Lp, labial palpus. L, ligula, consists of the two flaps below mentum. Enlarged seven and one-half times.
of the mentum is the cres- cent-shaped submentum. (Fig. 197, S.)
The gula and the palpiger are inconspicuous parts, which will not readily be made out without the aid of a compound lens.
1 The basal portion of the maxilla is composed of a rectangular sclerite called the stipes, connected at the distal end with the lacinia, and at the proximal end with the small, two- jointed cardo. The larger joint of the cardo is somewhat triangular.
260
ELEMENTARY STUDIES IN INSECT LIFE
Make a drawing of the labimn, and name the parts apparent with the lens in use.
Hypopharynx.— - The hypopharynx, marked in Fig. 209 H, situated between the maxilla and arising from the back wall of the mouth, may be readily made out.
THORAX.
The thorax consists of three divisions : the prothorax, bearing the front pair of legs ; the mesothorax, bearing the front wings and the middle pair of legs ; the meta- thorax, bearing the hind wings and the last pair of legs.
Prothorax.
The prothorax is made most conspicuous by the pro-
notum, the large sunboimet- shaped piece covering the dorsal portion of the thorax and extending back over the mesothorax and enveloping the lateral portions of the prothorax. This pronotum is divided into four parts, be- ginning with the cephalic or
FIG. 198. side view of prothorax front part. They are named
(Fig. 198): a, pnrscutum ; &, scutum ; c, scutellum ; d, post scutellum.
Just beneath, or ventrad of the scutellum, is a small tri- angular piece called the epi- sternum of the prothorax. The under and ventral por- tion of an insect is spoken of as the sternum; the side
with leg. a, prsescutum ; b, scutum ; c, scutellum; d, post scutellum; e, episternuru ; m, membrane, con- necting head with prothorax, con- taining the jugular sclerites ; /, coxa of leg ; 0, trochanter ; ft, fe- mur ; i, tibia ; j, tarsi ; fc, pulvillus and two claws. Enlarged three times.
FORM AND FUNCTION
261
or lateral portion is the pleiirmn ; and the upper or dorsal portion is the notnm.
Do the sutures dividing these sclerites extend down to the ventral margins of the pronotum? Make a drawing of the lateral view of the prothorax.
Prothoracic Leg1. — For study it will be better to remove the leg from the body.
Coxa. — Xote the globular joint. This is the coxa. (Fig. 198, f.)
Trochanter. — This second segment is a short, much smaller segment than the coxa, and more readily seen from the inner side. (Fig. 11 IS, r/.)
Femur. — The next segment of the leg is the femur. This is the largest and most prominent portion of the leg. (Fig. 108, ft.)
Tibia. — Continuing outward, the next segment is the tibia, a segment more slender than the femur. How does the inner margin differ from the inner margin of the femur? (Fig. 198, /.)
The rest of the leg is composed of a number of freely movable segments, known collectively as the tarsi. In the grasshopper there are three of these movable joints, the outer or end one bearing a pair of claws and a horse- hoof-shapcd pulvillus between the claws.
Make a drawing of the thoracic leg.
Mesothorax.
In order to study the mesothorax, remove the pro- thorax. We will study first the lateral view, then the ventral view, and lastly the dorsal view.
Episternum. — Extending from the front half of the mesothoracic coxa, dorsad to the base of the first pair of
262
ELEMENTARY STUDIES IN INSECT LIFE
A.
B.
FIG. 199. Side view of thorax, larged three times. A, Mesothorax. a, parapteron. 6, episternum.
c, epimeron.
d, wing.
En-
B, Metathorax 6', episternum. c', epimeron. d', wing.
wings, is the episternum of the mesothorax. ISTote that this part-way surrounds the socket of the leg, and articu- lates with the lateral margin of the sternum beneath.
Students at this time will carefully distinguish the difference between color markings and sutures proper. (Fig. 199, Z>.)
Parapteron. — Just cepha- lad or in front of the meso- thoracic wing is a very small triangular sclerite, the parapteron. This sclerite is inconspicuous, and not readily discerned. Epimeron. — Extending from the base of the front wing to the socket of the mid- dle leg lies the epimeron of the mesothorax. (Fig. 199, c.) Make a drawing of the lat- eral aspect of the mesothorax. Ventral View. — Between the nicsothoracic legs, forming the ventral surface of the mesothorax, is a prominent quadrangular sclerite, nearly straight on the front margin, but on the median line of caudal margin there is a well-developed dovetailed structure, making a notch in this segment. (Fig. 200.)
FIG. 200. Ventral view of thorax. Pro. St., prosternum ; Mesa. St., mesosternum ; Mtta. St., metaster- num. Enlarged about three times.
broad
FORM AND FUNCTION
263
Make a drawing of the ventral aspect of the meso- thorax.
Dorsal View.— -Lying- between the mesothoracic wings is a quadrangular piece, with a raised shield-shaped center. This is the mesonotnni. (Fig. 202, (7.) Typ- ically speaking, the notum of each division of the thorax should be composed of four sclerites, bearing the same names as those already given the pronotnm. In this case we cannot locate them, since the sutures are not clearly marked. The first segment, the prsescutum, is a very narrow plate, a mere line, not easily made out.
Metathorax.
Dorsal View.— The shape and divisions of the meta- thorax are similar to those of the mesothorax. As in the mesothorax, the sutures cannot be satisfactorily defined.
Lateral View.— - The lateral aspect of the metathorax shows it to be composed of two sclerites, the episternum and the epimeron.
Episternum.— - This sclerite extends from the front half of the hind coxa to the base of the hind wing. (Fig. 109, b.)
Epimeron. — Immediately joining the caudal margins of the episternum is the epimeron, which likewise ex- tends from the leg socket to the base of the wing. Add a drawing of this lateral view of the metathorax to the lateral view of the mesothorax already drawn.
Ventral View. — On the ventral part of the metathorax there is but one sclerite, the metasternum.
The Metasternum. — Lying immediately caudad of the mesosternum there is a large sclerite, the central part
264
ELEMENTARY STUDIES IN INSECT LIFE
of which dovetails into the mesosternnm. This is the metasternum. (Fig. 200.) Note that the first abdom- inal segment is likewise dovetailed into the posterior margin of this segment.
FIG. 201. Metathoracic, or jumping leg. c, coxa ; <r, trochanter ; /, femur ; ti, tibia ; ta, tarsi ; p, pulvillus and two claws. Enlarged four times.
Metathoracic Leg - - The metathoracic leg, though somewhat different in appearance from the prothoracic leg, already studied, is composed of a like number of parts and bearing the same relative positions and names as given in the study of the prothoracic leg. Draw the metathoracic leg, and name the parts. (Fig. 201.)
The Wings.
The two pairs of wings on each side are membranous expansions of the body-wall. They are composed of membrane strengthened by many thickened portions ex- tending the length of the wings. These thickenings are
FORM AND FUNCTION
265
B.
called veins or nerves. In the grasshopper the struc- ture and shape of the two wings on one side differ very materially. (Fig. 202, w w.)
Mesothoracic Wing.— This is frequently called the tegmen. It is long and narrow, and heavier than the metathoracic wing. (Fig. 202.)
Metathoracic Wing. - - The metathoracic
FIG. 202. Dorsal aspect of body (female). A, head : i, antenna ; 2, epicranium ; 3, compound eye. B, prothorax : a, pnescutum; 6, scutum ;.c, scutellum ; d, post scutellum. C, mesonotum: se, scutum; scl, scutellum; to, tegmen, or wing-cover. D, mi-tano- turu : ac, scutum ; scl, scutellum ; ic, wing. E, abdomen : ;, L', 3, 4, 5, S, 7, 8, 9, 10, 11, segments ; aw7, auditory organ ; sp, spiracles ; ,•, cerci ; pp, podical plates ; o, ovipositor. Enlarged about three and one-half times.
wings are Lroad and fan-like, capable <>t he- ing folded in plaits, and are concealed along the sides under the tegniina when not in use. Since these arc relied upon for the principal
266
ELEMENTARY STUDIES IN INSECT LIKE
means of flight, they are commonly called the wings.
(Fig. 202.)
THE ABDOMEN.
Among writers upon this subject there exists a differ- ence of opinion concerning the number of segments com- posing the abdomen. It will be evident to the observer here, upon a careful examination, that there are eight segments on the dorsal aspect of the abdomen of the female, and nine clearly shown on the same portion of the male. As will be seen from Fig. 202, we have con- sidered the .segments caudad of segment eight in the female, and segment nine in the male, as parts of the dorsal portion, and have numbered them accordingly.
The First Segment- - The ventral portion of this seg- ment is dovetailed into the metasternum, and by some authors has been considered a part of the metasternum. The ventral portion is widely separated from the lateral portion of the same segment, by the insertion of the hind leg.
The Auditory Organs. - - Just
dorsad of the leg in this seg- ment is to be found on each side an oystershell-shaped open- ing, covered by a membrane. These are the organs of hearing, or auditory organs, and the mem- brane covering them is the tym- panum.
Second to Eighth Segments — The second to the eighth seg-
FIG. -203. Exterior view of auditory organ. Sp, spiracle. Clear space is tympanum. Small dark body in center is vesicle, which is connected by vein to ganglion shown at right. Enlarged fifteen times.
ments are each ring -like in form.
FoKAl A.\D
267
The connection between the ventral portion of each of these segments with the lateral portion is not a suture, but is made by a membrane. This membrane can be most readily seen in the living insect during respiration. The lateral and dorsal portions of these eight segments show no dividing suture.
Caudal Portion of Abdomen of Male.— - The ninth and tenth dorsal segments are united on their lateral mar- gins ; the eleventh segment is flattened and furrowed by three deep longitudinal grooves.
FIG. 204. Side view of male. 7, K, 9, 10, 11, seg- ments ; c, cerci. Enlarged about three times.
FIG. 205. Dorsal view of caudal appendages of male. 6, 7, H, 9, 10, 11, segments ; c, cerci. Enlarged about three times.
On each side, projecting candad from beneath the lateral margins of the tenth tergum and curved upward, are the two appendages called the cerci. In this species they are slightly forked.
Immediately beneath or within these cerci can be seen
».
two narrow plates, more readily distinguished at their caudal extremity. These are the podical plalcx.
This last of the ventral segments consists of a h 1-
shaped piece, rounding up over the caudal end of the body into a blunt point.
Make a drawing of the dorsal and lateral views of the abdomen of the male, naming the parts.
268
ELEMENTARY STUDIES IN INSECT LIFE
Caudal Portion of the Abdomen of the Female.- - The
eleventh segment is somewhat rounded, and is crossed by a transverse ridge.
The Cerci are situated similarly as in the male, and are much shorter and not forked.
The Podical Plates have the same position relative to the cerci as in the male, and are more prominent, curving up under the eleventh dorsal segment.
Ovipositor.— - The most prominent portion of the caudal extremity of the female is the ovipositor. This consists of four horny-tipped pieces, outward curved at the extremities. For their use and the man- ner of using, see Figures 11, 206, and page 9.
Egg Guide.— - The caudal margin of the last ventral segment extends dorsad between the two lower pieces of the ovipositor. This forms the egg guide.
FIG. 206. Side view of abdomen (female). 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, seg- ments ; Sp, spiracles ; aud, auditory organ ; o, ovipositor ; pp, podical plates ; c, cerci ; /, forked organ. Enlarged about three times.
JMake drawing of the lateral and dorsal views of the abdomen of the female.
Spiracles.— Just cephalad of the socket of the meso- thoracic leg and a little above, is a small slit-like organ. Watch this in the living insect and you will notice two small valves or lips opening and closing.
FORM AND FUNCTION
269
% I
)' /
FIG. 207. Side view, showing spir- acle of mesothorax with spiracle en- larged.
This is one of the openings of the respiratory system.
It is called a spiracle. Ex-
•
;ii i line the body of the liv-
ing grasshopper and locate, if you can, other spiracles.
INTERNAL DIVISIONS OF THE BODY.
The grasshopper, agreeing with higher forms of life, has a digestive, circulatory, reproductive, respiratory, excretory and nervous system. With the facilities at hand we shall not be able to study all of these thor- oughly. However, by means of the dissecting-stand, lens, and with the addition of a pair of needles, we can obtain some interesting facts.
DIGESTIVE TRACT.
Take a freshly killed specimen, clip off the wings, pin the body down by the legs to a sheet of cork or thin piece of some soft wood, and with a sharp-pointed pair
270
ELEMENTARY STUDIES IN INSECT LIFE
FIG. 208. Digestive system of bae, magnified ten times (after Cheshire). A, horizontal section of body ; 7p, labial palpus ; mx, maxilla ; e, eye ; dv, di\ dorsal vessel ; v, ventricles of the same ; No. 1, No. 2, No. 3, salivary gland systems, 1, 2,3; us, oesophagus ; pro. t, prothorax ; mesa, t, mesothorax ; meta. t, metathorax ; #, 0, ganglia of chief nerve chain ; n, nerves ; hs, honey sac ; p, petaloid stopper of honey sac or stomach mouth ; c. a, chyle stomach ; 6t, biliary or malplghlan ves- sels ; si, small Intestine ; ?, lamellae or gland plates of colon ; H, large Intestine.
KOR.M AND FUNCTION
271
of small scissors open the specimen on the median line of the back, the full length of the body. Be careful not to cnt deeper than the body-wall, lest the internal organs be disturbed ; pin down the sides of the body to the cork. The specimen is now ready for study npon the dissecting-stand.
The specimen can be more readily manipulated if the block or cork of wood holding it be placed in a vessel containing just enough water to cover the speci- men. The internal organs will float out and stand up more distinctly.
FIG. 209. Digestive, circulatory and nervous systems of female grasshopper. 1, 2, 3, 4, 6, 6, 7, 8, 9, 10, 11, 12, segments; a-a, digestive tract; H, hypopharynx ; Lb, labium; Lm, labrurn ; Lp, labial palpus ; mp, maxillary palpus ; (J?, tesophagus ; pp, ovipositors ; eg, egg guide ; co, colon ; r, rectum. The heart is an open tube running along the back; it is so marked, but not easily shown. Enlarged three times.
The digestive system begins with the masticatory organs of the mouth, previously shown. (Figs. 193, 195.) The food is here masticated and mingled with the saliva secreted by glands lying under the esopha- gus. From the esophagus it passes into the crop, where it is retained until mixed with the saliva. The food then enters the gizzard-like proventriculus ; the inner walls of this are lined with chitinized processes, which, by a series of contractions, grind up the food
272
ELEMENTARY STUDIES IN INSECT LIFE
and pass it into tlic stomach proper. Lying alongside this stomach, and connected with it, can be seen on each side three long tubes. These are glands (pouches or ceca), and secrete a fluid which enters the stomach. It passes forward into the crop, and acts upon the food there also. From the proximity to the stomach, these pouches are frequently called gastric ceca. Pla- t <';i u and other writers equally authentic, claim that the digestive properties of the fluid secreted in them agree with the pancreatic juice of vertebrates.
The food, after leaving the stomach, passes into the intestines, the upper part of which is called the ilenm, the middle part the colon, the terminal part the rectum. At the forward end of the ileum can be seen a large number of tubes (malpighian tubes) running backward. These are believed to perform the functions similar t<> that performed by the kidneys in the higher animals. While the food is in the stomach, and as it passes through the ileum and the colon, the nutritive portions oozing through the walls of this digestive tube enter the circulation. The waste material is carried off through the rectum.
Make a drawing of the dorsal view of the alimentary canal, and name the parts.
NERVOUS SYSTEM.
Cut the caudal extremity of the alimentary canal ; pin this far enough to the side to allow free view of the whole tract immediately beneath. Here can be seen the nervous system. It consists of a series of ganglia, or masses of nervous matter, situated under the di- gestive canal. These ganglia are arranged along the body just next to the digestive tract. They are placed
FORM AND FUNCTION
273
together, in pairs, three pairs in the thorax and five pairs in the abdomen. They are joined to each other and to the ones of the corresponding side by a cord of nerve tissue known as a commissure. This forms a double chain from the back part of the body up to the head, where a nerve band is formed around the esopha- gus; on the top of the esophagus are to be found the two largest ganglia in the body of the insect. From these ganglia, nerves proceed to various parts of the head. From these there go out brunches of nerves fo the eyes, to the antennae, to the maxilla- and mandibles, and to other parts of the face.
Make a drawing showing the nervous system and the position of the ganglia with reference to their respective segments on the -body.
FIG. 210. Respiratory system. Sp, spiracles, showing trachea) permeating all parts of the body ; S, air-sacs, which aid flight. Enlarged three times.
RESPIRATORY SYSTEM.
This insect, instead of having one portion of the body set apart for the purification of the blood, similar to animals possessing lungs, may be said to have lungs all over its system; that is, there are trachea1 branched and branched until thev cover everv part of the system
•. • JL t
—18
274 ELEMENTARY STUDIES IN INSECT LIFE
and extend to every organ in the system. These trachea do not depend upon the month for their supply of air, but are connected with the body-wall direct, the outer portion of this connection being known as spira- cles. (Figs. 206, 210.) These spiracles have valves and openings which close and open at intervals, allowing free interchange of air. The trachea? which run from these spiracles are membranous tubes, which do not collapse, because they are kept open by continuous rings of cartilage, similar, though on a smaller scale, to the cartilage in the windpipe of those animals pos- sessing lungs. This distribution of air within the body tends to make the insect lighter and more cupahlr of flight. In addition to these trachea, however, there are organs especially made to assist in buoying the in- sect when on the wing. These are commonly known as air-sacs, and connect with the spiracles as .shown in the figure. (Fig. 210.)
In a live insect, notice under the lens the action of the spiracle situated just in front and dorsad of the base of the mesothoracic leg. If the student will for a time watch this spiracle it will be seen to have two lips, and that these open and close in unison with the expansion and contraction of the body-wall. This movement of the body is more manifest in the abdo- men. Figure 207 shows this spiracle much enlarged.
Take out one or two of the largest trachea? found, and study their structure by tearing them apart on the dissecting-table under the lens. When the trachea are pulled apart with the needles, do they sometimes appear still to be connected by a thread which ravels
FORM AND FUNCTION
275
off from each fragment like thread from a spool ? This thread is the coiled structure which prevents the trachea1 at all times from collapsing.
Keturn to your outline-drawings of the external an- atomy, and locate the mesothoracic abdominal spiracle.
CIRCULATORY SYSTEM.
In this locust, there are no arteries and no veins. The circulatory system, so far as organs are concerned, is comprised of what we are wont to call the heart. This organ is a tube extending from about the tenth segment of the abdomen up into the head. This tube has valves along its sides which admit of entrance of blood, and do not allow that which has entered to escape until it passes out of the main opening at the end of this organ in the head.
The blood of insects differs from that of some other animals, in having no red corpuscles. It is a thin fluid, and is a mixture of blood and chyle, usually colorless, but sometimes yellowish or reddish. It is carried forward by this tube or heart to the front end, and then flows back, nourishing the organs as it- passes, and likewise coming in contact with tracheae, which are everywhere present in the body. When in contact with these trachea, action similar to that in the human lung takes place. It will be seen that the chief function of this heart is to conduct forward the newly made blood and unused blood from the back end of the body, pour it out at the front end of the body, and allow it to flow back like a river in its course. The action of the heart can be seen with the naked eye, or still better, through the haiul-leiis, in some cater-
276
ELEMENTARY STUDIES IN INSECT LIFE
pillars with light color and delicate skin, when they are held between the observer and the snn.
REPRODUCTIVE SYSTEM.
Should a female be examined a few clays previous to the time of oviposition, the ovary will be found much distended and containing about one hundred eggs. These eggs are carried out through the egg-duct and
FIG. 211. Reproductive system of female grasshopper. Large egg-sac lying above stomach ; ovi- (kict leading out above egg-guide (the external opening of oviduct is above point where duct is cut by this sectional figure) ; r, rectum ; a-a, digestive tract. Enlarged three times.
placed in position in the ground in the manner previ- ously shown. If eggs are present in the specimen now studied, make a drawing of the lateral view of the whole ovary and of one of the eggs.
THE BEETLE.
That some conception may be obtained of the dif- ferences and resemblances existing between the relative parts in different insects, the anatomy of the rummag- ing ground-beetle1 is outlined.
This is not an uncommon insect, and can be found in the woods around decaying logs, or under rocks. It
}Calosoma scrutator. Any of the larger beetles belonging to the Carabidae, the ground-beetle family, will do.
FORM AND FUNCTION
277
is about an inch long and a half-inch broad. The legs, top of head, and prothorax are purple, the wing-covers dark green with wine-red borders.
The beetle, after being treated with cyanide, as in the case of the grasshopper, should be boiled in water
FIG. 212. Rummaging ground-beetle (Calosoma scrutator). Enlarged.
until the parts separate easily. The different parts can be readily separated under the lens upon the dis- secting-stand.
Upon a piece of white cardboard, eight by fourteen inches, fasten neatly, with a good quality of glue, the several parts in order, following the method shown in Figure 213.
Name the movable parts of the head.
278 ELEMENTARY STUDIES IN INSECT LIFE
FORM AND FUNCTION
279
Name tlio divisions of the body.
Name the appendages of the body.
Name the segments of the legs on one side of the body.
It will be found more convenient to number the divisions and segments, then write the numbers and corresponding names in a column on the right-hand side of the card-mount.
Boil another specimen of the same beetle ; separate the parts. With a specimen of the yellow grasshopper in hand and the drawings previously made thereon, make careful observations on the comparative size, shape and relative positions of the following parts of the two insects, and place them in writing:
The head.
The prothorax.
The mesothorax.
The metathorax.
The abdomen.
The mandibles.
The maxilla?.
The eyes.
The prothoracic leg.
The mesothoracic leg.
The metathoracic leg.
The wing-covers (elytra).
The wings proper.
MOUTH-PARTS OF THE CICADA.
Since the mouth-parts of all insects are of two types, mandibulate and haustellate, it is proper that the student should be familiar with the structure of each. The mouth-parts of the grasshopper and the beetle are
280 ELEMENTARY STUDIES IN INSECT LIFE
examples of the mandibulate type. The mouth-parts of the cicada, sometimes called harvest-fly or locust, illus- trate the structure of the haustellate mouth. Specimens just from the cyanide bottle or preserving-fluid can be studied without further preparation. Dried speci- mens will require boiling in water until soft and plia- ble. Remove the head with the beak from the body of the specimen ; examine the beak before dissecting.
The primitive or earlier insects had biting mouth- parts ; the haustellate or sucking mouth is a later de- velopment. This mouth structure is therefore a special- ized form. That is, it has been peculiarly developed for a certain purpose, from, we are led to believe, the primitive mandibulate mouth. So, in discussing these sucking mouth-parts, it is the endeavor to trace each back to its primitive organ. The terms used, then, in naming the organs of the sucking mouth, are as far as possible the same as those used in naming the parts of the biting mouth. These terms, such as mandible and maxilla, are not used to name the parts of the sucking mouth to signify that they are used for chew- ing. The parts are so designated because it is gen- erally believed that the parts so named were once a true mandible or a true maxilla. But certain condi- tions arose which made it necessary for these insects to secure their nourishment from the juices under the bark of trees, instead of chewing the foliage. These biting mouth-parts gradually developed by long use into tube-like structures adapted to the required work.
The names given these are given, therefore, because it is generally believed that the sucking mouth-parts, so named, represent the present development or condition
FORM AND FUNCTION
281
of the corresponding part, the one bearing the same name in the biting mouth. That is, we say the parts are homologous.
What are the conditions which might arise to cause this peculiar and interesting development ? Let us sup- pose that, leaf- and vegetable-feeding insects became so numerous as to devour or greatly reduce the whole food supply. Is it not evident that many insects would perish \ But, if some of these insects find it possible to secure nourishment from beneath the bark of trees and dense outer covering of plants, the leaves of which have al- ready been eaten, will they not have a better chance to exist than
FIG. 214. Head of cicada, showing rnouth-
tllOSe wllOSe dependence parts. Tip of mandible and maxilla en- is wholly upon the foli- larged' at the left age? Insects which have learned to extract the juices, finding this an easy and uncontested way of obtain- ing sustenance, continue to seek nourishment in such places. Succeeding generations having used the mouth constantly in this way, this mouth has developed and adapted itself to the work in hand, until at present there exists a well-established mechanism for the imbibing of fluids.
282 ELEMENTARY STUDIES IN INSECT LIFE
With these points clearly in mind, take up the study of the cicada. Pin the head on a piece of cork, with the front of the head upward. With the dissecting-needle carefully draw out the mouth-parts contained in the long tube, the three-jointed labium. Trace these needle- like parts as near to the head as possible. How many of these needle-like parts are there? (See Fig. 214.) Each of these needles passes within the head. The larger ones are the mandibles, the smaller ones are the max- illa^. If a compound microscope is at hand, make an examination of the tips of a mandible and of a maxilla. These mandibles and maxillae are used, not for biting, but for boring or cutting through the outer layers of trees and plants. It is likely that they also aid in bringing the juices into the esophagus.
KEY TO THE OKDEES
283
CHAPTER VI.
KEY TO THE ORDERS AND THE PRINCIPAL FAMILIES
OF INSECTS
Definition — Hexapoda.— - Insects belong ,to the class Insacta or Hexapoda. They are small animals with bodies divided into three parts, — head, thorax, and abdomen. These are placed in longitudinal succession. They breathe, take air, by means of trachea ramifying throughout the body. The main trunks of the trachea
O «/
open externally at orifices (spiracles) situated at the sides of the body. As appendages they have one pair of antenna?, situated on the head, six legs attached to the thorax, the middle division of the body, four wings in some cases, in others two, always placed on t he- thorax. In some instances insects have no wings. The insect body is composed of a succession of transverse rings or segments, marked in some, obscure in others. It is generally conceded that the number of these rings never exceeds thirteen. This ringed or segmented condition is more marked in the earlier stages of in- sect life. The number of articulated legs is six. In the developing stages these may be present or absent.
ORDERS.
A. — Insects, wingless and without rudimentary wings, showing no evidence of having descended from winged ancestors. Three pairs of legs. Metamorphosis slight. APTERA.
AA. — Insects, winged, or having rudiments of wings, showing evidence of having descended from winged ancestors. Meta- morphosis varied.
284 ELEMENTARY STUDIES IN INSECT LIFE
B. — Mouth-parts biting, four wings.
C. — Front wings leather-like, usually narrower than hind wings, which are delicate, and fold in repose in the man- ner of a fan. Metamorphosis incomplete.
ORTHOPTERA.
CC. — Front and hind wings similar in texture, frequently with many cross-veins forming a network. Little or no fan-like action in the closing of hind wings. Metamor- phosis incomplete in some forms, complete in others.
NEUROPTERA.
CCC. — Wing-covers, i.e., .the upper pair, shell-like, meeting
in a straight line along the back, forming cases over and
concealing the delicate infolded membranous wings proper.
Metamorphosis complete. COLEOPTERA.
CCCC. — The four wings membranous. Front wings larger
than hind wings; hind wings always small, and not folding
fan-like in repose. Mouth-parts mandibulate, but in many
forms there is present a tubular proboscis; the mandibles
being in the form of jaws and the maxillae and labium
fitted for taking liquid food. HYMENOPTERA.
BB. — Mouth suctorial. Four wings.
C. — Mouth perfectly suctorial.
D. — The front pair wings leather-like, with more mem- branous apex (Heteroptera — see page 184), or entire wing parchment-like or membranous ( Homoptera — see page 185.) Metamorphosis incomplete.
HEMIPTERA.
DD. — Four large wings covered with scales. Metamor- phosis complete. LEPIDOPTERA. CC. — Mouth imperfectly suctorial. Four very narrow fringed wings. Very small insects. Metamorphosis incom- plete. THYSANOPTERA. BBB. — Mouth suctorial, mandibulate and maxillate bristles present in some forms, and used for piercing. Two wings, the hind wings being represented by a pair of knobbed, thread-like organs. Metamorphosis complete.
DIPTERA.
APTERA.
A. — Abdomen composed of ten segments; ventral tube wanting
on its first segment. Suborder Thysanura.
(Fish Moths.)
KEY TO THE ORDERS
285
AA. — Abdomen composed of not more than six segments, the first
being furnished with a ventral tube. Suborder Gollnnbohi.
(Spriugtails.)
ORTHOPTERA.
A. — Posterior femora fitted for walking, i. e., resembling those of the other legs. Organs of flight of immature forms in normal position. Insects mute.
B. — Anterior wings leathery, very short, without veins, meet- ing in a straight line; posterior wings when present folded to the middle of the anterior margin; tarsi three-jointed, the pulvillus wanting; cerci horny, resembling forceps.
Forficulidae.
(Earwigs.)
BB. — Anterior wings parchment-like, thickly veined ; posterior wings folded to the base, (except certain Phasnudac, which are wingless); tarsi five-jointed; cerci soft, jointed or with- out joints.
C. — Body oval, depressed; head wholly or almost wholly withdrawn beneath the pronotum ; pronotum shield-like, transverse; legs compressed; cerci jointed; rapid- running insects. Blattidar.
(Cockroaches.)
CC. — Body elongated; head free; pronotum elongated; legs slender, rounded; cerci jointed or without joints; walking insects.
D. — Front legs fitted for grasping; cerci jointed.
Mantidae. (Praying Mantis.)
DD. — Front legs simple; cerci without joints.
Phasmidac. (Walking-Sticks.)
AA. — Posterior femora fitted for jumping, i. r., very much stouter or very much longer, or both stouter and longer, than the middle femora; organs of flight of immature forms reversed; stridulat- ing insects.
B. — Antenna3 shorter than body; tarsi three- jointed ; organs of hearing situated in the first abdominal segment; stridulat- ing organs situated in hind femora and the costal area of
the tegmina. Acrididac.
( Grasshoppers.)
BB. — Antenna1 longer than body, setaceous; tarsi four- or
286 ELEMENTARY STUDIES IN INSECT LIFE
three-jointed; organs of hearing situated in the anterior tibae and also in the prosternum.
C. — Tarsi four-jointed; ovipositor (when exserted) form- ing a strongly compressed, generally sword-shaped blade.
Locustidfte. ( Katydids.)
CC. — Tarsi three-jointed; ovipositor (when exserted) form- ing a nearly cylindrical, straight, or occasionally up- curved needle. Gri/lliddc.
(Crickets.) NEUROPTERA.
A. — With four or two wings well developed.
B. — Antennae inconspicuous, awl-shaped, short and slender. C. — First and second pairs of wings nearly of same length ;
tarsi three- jointed. Libclliiliduc.
(Dragon-Flies.)
CC. — Second pair of wings either smaller or wanting; tarsi four- or five-jointed. Ephcmcridm:
(Day-Flies.)
BB. — Antennae usually conspicuous, setiform, filiform, clavate, capitate, or pectinate. C. — Tarsi two- or three-jointed ; wings unequal.
D. — Hind wings smaller. Psocidae.
(Book-Lice.)
DD. — Hind wings of same size, or broader than fore wings; anal area large, of simple venation, folded.
Perlidae.
(Stone-Flies.) CC. — Tarsi four-jointed; wings unequal. TcnnHidnc.
( White Ants.)
CCC. — Tarsi five- (sometimes apparently but four-) jointed. D. — Hind wings with no anal space, not folded. E. — Mouth more or less prolonged into a beak.
1'i/iwrjiidae. (Scorpion-Flies.) EE. — Mouth not prolonged into a beak.
Hcmerobidae. (Lacewing-Flies.) DD. — Hind wings with a folded anal space.
E. — Wings reticulate. Sialidae.
(Dobson-Flies.)
EE. — Transverse veins rather few. Phryganeidae.
(Caddis-Flies.)
KEY TO THE OKDKl.'S
287
AA. — Wings rudimentary or wanting. B. — Mouth prolonged into a beak.
BB. — Mouth not prolonged iuto a beak. C. — Tarsi five-jointed.
Panorpidae.
(Certain Scorpion-Flics.)
CC. — Tarsi four-jointed.
Phri/gancidar. (Certain Caddis-Flies.)
Tcrmitiditc. (Certain White Ants.) CCC. — Tarsi two- or three-jointed.
D. — Wings absent; or two rudimentary, leathery.
Psocidae. (Certain Book-Lice.)
DD. — Four rudimentary wings, veins visible.
Perlidae.
(Certain Stone-Flies.)
CCCC. — Tarsi one- or two- jointed. Mallophagidae.
(Bird-Lice.)
COLEOPTERA.
A. — Head not prolonged into a narrow beak, B. — Tarsi five-jointed.
c. d.
FIG 215. Various forms of antennfe of beetles, a, filiform, or thread-like ; 7>, serrate, or saw-like ; e, pectinate, or comb-like ; d, lamellate, having an enlarged end, composed of plates.
C. — Antenna? with terminal joints leaf-like (lamellifonn ; i.e., broader and flatter than basal segments.) (Lamelli- cornia.)
D. — The ventral surface of abdomen divided into five seg- ments; elytra cover entire dorsal surface of abdomen;
288
ELEMENTARY STUDIES IN INSECT LIFE
mandibles in males large, and armed with projections
or teeth. Lucaniilm.
(Stag Beetles.)
DD. — The ventral surface of abdomen divided into six segments; elytra do not usually cover entire dorsal sur- face of abdomen. flcarabacidae.
(Chafers ; June-Bugs.)
CC. — Antenna? never lamelliform, but thread-like or nearly so. (Adephaga.) D. — Legs fitted for running. Terrestrial insects.
E. — Clypeus extending laterally in front of base of antennae; i.e., antennae inserted in front above base
of mandibles. Cicindclidae.
( Tiger Beetles.)
EE. — Clypeus not extending laterally in front of base of antennae; i.e., antenna- coming from the side of the
head between base of mandibles and the eyes.
Cardbidae.
(Ground Beetles.) DD. — Legs, especially the hind legs, fitted for swimming;
not capable of ordinary walking. Di/tiNci<lu<:
( Predaceous Diving Beetles.)
BB. — Front and middle tarsi five-jointed, hind tarsi four-jointed. (Heteromera.) C. — Prothorax wider than head ; front coxa1 separated, not protruding; body
and wing-covers firm. Tciu-bi-ion'nl<n-.
(Darkling Beetles )
CC. — Prothorax narrower than head ; front coxae near together, protruding;
body and wing-covers soft. Meloidae.
( Blister Beetles.)
BBB. — Tarsi four-jointed (apparently), but with a small indistinct joint between the third and fourth clearly visible segments. (Phytophaga.) (See Figure 210.) C. — Body elongate, antennae long, fre- quently as long as the body or longer;
the larvae are borers. Cerambycidae.
(Long-horned Beetles.)
CC. — Body short, more or less oval, an- tenna? short. Chrysomclidae.
( Leaf Beetles.)
FIG. 216. Tarsi of beetle, showing indistinct fourth segment. (After Comstock.)
KEY TO THE ORDERS
289
BBBB. — Tarsi variable, antennae club-shaped; i.e., the distal joints enlarged; or antennal joints from third outward inure or less saw-like, the saw-teeth being on the inner edge. (Polymorpha. ) C. — Tarsi five- jointed.
D. — Maxillary palpus as long or longer than the antennre.
Hydrophilidae.
( Water Scavengers.)
DD. — Maxillary palpus plainly shorter than the antennae. E. — Abdomen with seven or eight visible ventral seg- ments. Integument soft. Lami>ijfi<lmi.
(Lightning-Bugs.)
EE. — Abdomen with five visible segments ; integument firm.
F. — Anterior coxae globular, and projecting but little from the coxal cavities.
G. — Hind angles of prothorax more or less prolonged backward. Prothorax fitting loosely to the after- body, thus admitting free nodding movements.
Illdtcridae. (Click Beetles.)
GG. — Hind angles of prothorax not prolonged back- ward. Prothorax fitting closely to after-body, per- mitting no nodding motion. Bii]ircKti/l>i<.
(Metallic Wood-Borers.)
FF. — Anterior coxa? conical, i. c., long, oblique, and projecting prominently from the coxal cavities. Small or moderate-sized beetles. Dcnm.^l iilne.
(Carpet Beetles ; Buffalo Moths.)
CC. — Tarsi apparently three-jointed (the apparent third joint consisting really of two small segments).
Coccincllidae. (Ladybirds.)
CCC. — Tarsi variable, being three-, four- or five-jointed. D. — Abdomen flexible, with seven or eight segments visible below ; elytra very short, leaving greater part of abdomen exposed. Stapluiliniilnr.
(Rove Beetles.)
DD. — Abdomen firm; elytra usually covering the body; (the elytra of some Silphidse are short, exposing at most the last three dorsal segments of abdomen.) E. — Legs fitted for swimming. C! i/rinidac.
—19 (Lucky-Bugs; Whirligig Beetles.)
290 ELEMENTARY STUDIES IN INSECT LIFE
EE. — Legs fitted for walking. Silphidae.
(Carrion Beetles.) AA. — Head prolonged in front, forming a beak.
Rhynchophora.
B. — Head drawn out into a proboscis. Antennae usually elbowed, i, e., basal joint longer, and when directed laterally the other
joints may be directed forward. Curculionidae.
(Curculios or Weevils.)
BB. — Head not drawn out into a proboscis; i.e., the beak is very short; antennae short with a broad club; tibia usually
toothed on the outer side. Scolytidac.
( Engravers.)
HYMENOPTERA.
A. — With abdomen broad at the base. The thorax and abdomen having a broad connection instead of being connected by a more or less thread-like joint. Extremity of female equipped with saw or boring apparatus, usually more or less concealed; vege- table feeders. (Phytophaga or Sessiliventres.) B. — Front tibia with two apical spurs; abdomen of female
equipped with a pair of saws. Tenthredinidae.
(Saw-Flies.)
BB. — Front tibiae with one apical spur; abdomen of female
furnished with a borer. Siricidae.
( Horn-Flies.)
AA. — The abdomen connected with what appears to be the thorax by a slender joint or petiole; in some long and thread- like, in others short. (Petioliventres.)
B. — Trochanters of two pieces, female with ovipositor. (Para-
sitica. ) ( Parasitic Insects.)
C. — Wings without a system of cross-veins forming inclosed
cells ; the main direction of the veins being lengthwise of
the wing. Chalcididae.
(Chalcis-Flies.)
CC. — Wings with well-developed series of veins and cross-veins.
Ichncumonidae. ( Ichneumon-Flies.)
BB. — Trochanters undivided, abdomen consisting of three, four or five visible segments. Insects of bright metallic colors ; abdomen convex above, flat or concave below. (Tubulifera. )
Chrysididae. (Ouckoo-Flies.
KEY TO THE ORDERS
291
BBB. — Trochanters undivided : abdomen composed of six or seven visible segments; female with retractile sting. (Aculeata.)
C. — Body with hairs on it more or less plumose. Apidae.
(Bees.) CC. — Hairs of body not plumose.
D.- — First abdominal segment (and sometimes second also) forming a knot or node on upper side. Formicidae.
(Ants.)
DD. — First and second abdominal segments without knot or node. E. — Wings folded in plaits when at rest.
F. — Tibiae of the middle legs with a single terminal spur, tarsal claws bearing a tooth. Eumenidae.
(Solitary Wasps.)
FF. — Tibiae of the middle legs with two terminal spurs ; tarsal claws not toothed. Vespidae.
( Social Wasps ; Hornets.) EE. — Wings not folded in plaits when at rest.
F. — Pronotum extending back on sides to the tegulse. (See Fig. 217.)
P t
FIG. 217. Drawn from specimen, by Miss M. E. Wise.
FIG. 218. Drawn from speci- men, by Miss M. E. Wise.
G. — Legs of normal length ; many wingless forms.
Scoliidae. (Underground Stingers.)
GG. — Legs very long; no wingless forms.
Pompilidae. (Runners.)
FF. — Pronotum not extending back to the tegulse. No
wingless forms. (Fig. 218.) Sphegidae.
( Thread-waisted Wasps; Mud-daubers.)
292
ELEMENTARY STUDIES IN INSECT LIFE
HEMIPTERA.
A. — Front of head not touching the coxse ; distal portion of wing generally thinner than basal part. (Hcteroptera.)
B. — Antennae as long as the head at least. Terrestrial Heter- optera excepting one family, Hydrobatidse. C. — Last segment of tarsi more or less split; claws arising from side of tarsi.
D. — Body usually elongate ; beak four-jointed ; tarsi two- jointed. Second and third pair of legs unusually long.
Hydrobatidae. (Water-Striders.)
CO. — Last segment of tarsus entire; claws arising from end of tarsi. D. — Antennae four-jointed.
E. — Wing-covers resembling network ; tarsi two-jointed.
Tingitidae.
(Lace-Bugs.)
EE. — Wing-covers of various forms or rudimentary, but not resembling lacework.
F. — Beak three-jointed, curved. Front femora some- what thickened. Reduviidae.
(Assassin-Bugs.) FF. — Beak four-jointed.
G. — Ocelli present.
FIG. 219. Wing of Coreidae, showing venation. (After Comstock.)
FIG. 220. Wing venation of Ly- gieidae. (After Comstock.
FIG. 221. Wing vena- tion of Capsidse. (After Comstock.)
H. — Antennae inserted on upper part of head; venation of wing according to figure.
Coreidae. (Squash-Bugs.)
HH. — Antenna? inserted well down on side of head; venation of wing according to figure.
Lygaeidae.
(Chinch-Bugs.)
GG. — Ocelli wanting; venation of wing according
to figure. Capsidae.
(Leaf-Bugs.)
KEY TO THE ORDERS
293
DD. — Antenna- five-jointed (rarely four-jointed) ; two ocelli, tibia bearing very short spines or none, tarsal claws with
appendages. Pcntatomidac.
(Stink-Bug Family.)
BB.— Antennse apparently absent, but really present, situated on under side of head and closely appressed to head, some- times placed in pocket in front of each eye. Aquatic Heter- optera. C. — Hind tarsi without claws.
D. — Fore tarsi of usual form, with two claws; head in- serted in prothorax. Not'tnn-tidac.
( Backswlmmers.)
DD. — Fore tarsi flattened with a fringe of hairs on the edge, and without claws. Head overlapping the prothorax.
Corisidae.
(Water-Boatmen.) CC. — Hind tarsi with two claws.
D. — Abdomen with terminal respiratory tube composed of two grooved thread-like organs. Not retractile. Legs not flattened for swimming. Yr/m/ur.
(Water Scorpions.)
DD. — Abdomen with two terminal strap-like appendages, retractile, frequently withdrawn from sight. Legs flat- tened for swimming. Belostomidae.
(Giant Water-Bugs.)
AA. — Front of head much bent inward so that it touches the coxae. Wings of same texture throughout. Suborder Homoptera. B. — -Tarsi usually three-jointed.
C. — With three ocelli, usually large insects; males possess
musical organs. Cicadidae.
(Cicadas.)
CC. — With two ocelli, males without musical organs.
D. — Antennse inserted on sides of cheeks beneath the eyes.
I'nlyoridae. (Lantern-Flies.)
DD. — Antenna? inserted in front of and between the eyes. E. — Prothorax prolonged backward into a hood or pro- cesses of varied forms. Mfinbrai-idae.
(Tree-Hoppers.)
EE. — Prothorax not prolonged backward. F. — Hind tibise armed with many spines.
Jassidae. (Leaf -Hoppers.)
294 ELEMENTARY STUDIES IN INSECT LIFE
FF. — Hind tibiae armed with one or two stout teeth,
with short stout spines at tip. Cercopidae.
( Spittle Insects.)
BB. — Tarsi usually two-jointed.
C. — Legs long and slender, not fitted for leaping; antennae
three- to seven-jointed. Aphididae.
(Plant-Lice or Green-Flies.)
CC. — Hind legs fitted for leaping; antennae nine- or ten- jointed. Psyllidae.
(Jumping Plant-Lice.)
BBB. — Tarsi usually composed of one joint. Minute in- sects; males with one pair of wings, females wingless and much degraded, so that most of the external organs and
appendages cannot be distinguished. Coccidae.
( Scale Insects.)
LEPIDOPTERA.
A. — Antennae knobbed at tip, or thickened near the tip; never feather-like or with process projecting from the sides. Hind wings without frenulum but with the humeral area of hind wing extended forward under the front wing. (Butterflies.) B. — First pair of legs different from the other pairs; gen- erally much smaller and not used as legs. C. — Front pair of legs very small, claws wanting.
NymphaUdae.
(Brush-footed Butterflies.)
CC. — Front pair of legs but little reduced in size; claws
present. Lycaenidae.
( Blues and Coppers.)
BB. — First pair of legs like the other pairs.
C. — Front tibiae without pads ; claws toothed.
Pieridae.
( Cabbage Butterflies.) CC. — Front tibiae with a pad.
D. — Claws large and simple; i.e., not toothed; antennae
generally straight at tip. Papilionidae.
(Swallowtails.)
DD. — Claws short and thick, and toothed at the base;
antennse generally recurved at tip. Hesperidae.
( Skippers.)
Before undertaking the systematic study of AA, the second group, or moths, an understanding of the wing structures of
KEY TO THE ORDERS
295
these insects is necessary. If the under side of the wing be moistened with benzine or chloroform, by means of a small camel's-hair brush, it will be noticed that the membranous portion of the wing is supported by veins or nervures. The relative positions of these veins remain fairly constant in the various families, and thus these veins afford clear and ready means of comparison. For these veins, various systems of arrangement and nomenclature are extant. The one used here was proposed by Redtenbacher, and has been modified and ex- tended by Comstock. The principal trunks of the veins bear the Roman numerals I, II, III, etc.; the branches of each of
Ux.j
FIG. 223. Wing of a Hepialid moth, showing plan of vena- . tion. (After Comstock.) FIG. 222. Wings of a Noto- dontid, showing venation. .F, frenulum. (After Comstock.)
these veins, where branches exist, are numbered III^ IIL, III3, etc. The system considers I (the front margin of wing) simple, II simple, III possessing five branches, IV with three branches, and V with two branches. Those main veins which come after V are called anal veins. They are generally simple. This ar- rangement has reference to the early or primitive plan of the wing. This condition is shown in Figure 222. This arrangement is greatly modified in some of the higher types, by the elimination of branches or even trunks and by the coalescence of veins for part or for their entire length.
AA. — Antennae of various forms, frequently feather-like, rarely knobbed at tip, but in such cases the hind wing bears a frenulum.
296
ELEMENTARY STUDIES IN INSECT LIFE
B. — Hind wings with three anal veins; small moths, palpi generally well developed; when palpi are not well de- veloped, antennae are at least as long as the front wings. Fringe on inner angle of hind wings longer than elsewhere. C. — The second anal vein of the hind wings forked near the base. Tortricidnc.
( Leaf-Rollers.)
CC. — The second anal vein of the hind wings not forked near the base. Tincidae.
( Leaf-Miners and Clothes-Moths.)
BB. — Hind wings with less than three anal veins; moths of
FIG. 224. Wings of a Geoniet- rid, showing venation. F, fren- ulum. (After Comstock.)
FIG. 225. Wings of a Noctuld, showing venation, (After Com- stock.)
medium or large size, palpi generally small ; antennae mod- erate in length. Fringe on inner angle of hind wing not noticeably longer than elsewhere.
C. — Vein IV2 of front wing standing midway between IV, and IV3 or nearer IVj than IV3. D. — Frenulum present.
E. — Antenna? in length spindle-shaped; i.e., thicker in the middle and tapering toward the tip and base; in breadth, i. e., in cross-section, shaped like a prism.
ftphingidae. (Hawk Moths or Humming-Bird Moths.)
KEY TO THE ORDERS
297
EE. — Antenna? not spindle-shaped, nor prismatic.
F. — Tarsi as short as tibia, hairy; stoutly built moths. Wing venation according to figure. ( Fig. 222.) Notodontidae.
(Proininents.) FF. — Tarsi long and naked; slightly built moth-.
Wing venation according to figure 224.
G-eometridae.
( Measuring-Worms. )
DD. — Frenulum absent ; humeral angle of hind wing extended forward under front wing; proboscis absent, legs without spurs. K<itnniii<l<i<:
(Cecropia Moths and others.)
FIG 226. Wings of an Arctiid, showing venation. (After Comstock.)
CC. — Vein IV2 of front wing arising from IV3 or si a tiding nearer IV3 than IV^ ocelli present: antennae bristle or thread-like; night- flying moths. (See Figure 225 for venation.)
D. — Vein II of hind wing distinct from vein III or united for but a very short distance near base of wing. (See Figure 225. ) Generally chill-colored moths.
Noctuidae.
(Owlet Moths.)
DD. — Vein II of hind wing united with III for a consid- erable distance from base. (See Fig. 226.) In many cases these moths are conspicuously striped or spotted.
Arctiidae.
(Tiger Moths.)
298
ELEMENTARY STUDIES IN INSECT LIFE
DIPTERA.
A. — Antennae with more than six segments, not ending in a style or bristle; palpi slender and flexible, four- or five-jointed. ( Orthorrhapha Nemocera. )
B. — Dorsum of thorax with a distinct V-shaped suture. (See Fig. 228.) Legs unusually long. Tipulidae.
(Crane-Flies.
FIG. 227. a, antenna of a Bombyliid ; ft, antenna of a Syrphid ; c, antenna of a Muscid ; d, antenna of a Tabanid. Drawn from specimens, by Miss M. E. Wise.
BB. — Dorsum of thorax without distinct V-shaped suture. C. — Margins of wings and each of the wing veins fringed with flat scales. Antennae with whorls of hair or plumes ; plume generally dense in male and sparse in female.
Culicidae.
( Mosquitoes.)
CC. — Margin of wing and each of wing veins without fringe of flat scales; antennae thick, straight, shorter than the thorax. Legs comparatively short
and stout. Bibionidae.
(March-Flies.)
AA. — Antennae three jointed, with distal joint marked with from five to eight rings or annuli. Bristle when present is us- ually at end, not on upper side of last segment. Palpi one- or two-jointed. (Or- thorrhapha Brachycera. )
B. — Antennae three-jointed, the second joint usually short. Third
segment frequently annulated. (See Fig. 227, d.) Tabanidae.
( Horse-Flies.)
BB. — Antennas three-jointed, the terminal joint not distinctly
FIG. 228. Thorax of crane-fly, showing V- shaped suture. (After Comstock.)
KEY TO THE OKDERS
299
divided. Body frequently fringed with down or covered with hairs, giving a bee-like appearance. Bombyliidae.
(Bee-Flies.)
BBB. — Antennae three-jointed, with terminal appendage of di- verse form and structure. Mouth forming a short, project- ing horny beak; strong feet. Predaceous flies. Asilidae.
(Kobber-Flies.)
AAA. — Antennae composed of not more than three joints and an arista;1 arista not arising from end of last segment; no arched frontal suture over the antennae. (See Fig. 227, 6.) ( Cyclorrhapha Aschiza. ) B. — Vein-like thickening between veins III and V. (See Fig.
226. ) Syrphidae.
(Hovar-Kieo.)
FIG. 229. Wing venation of a Syrphicl. (After Comstock.)
AAAA. — Antenna? consisting of three joints and an arista; frontal suture over antennae well marked, extending downward along each side of face. (Cyclorrhapha Schizophora.) B. — Arista on upper side of antennae. For wing venation see
Figure 230. Muscidae.
(House-Fly Family.)
FIG. 230. Wing of a Muscid. (After Comstock.)
The suborders Orthorrhapha and Cyclorrhapha, the main sub- divisions, chiefly based upon pupal characters, are omitted in this scheme. Instead of a dichotomous arrangement, the prin- cipal families of the order are placed under the four divisions of Brauer.
*A bristle-like appendage.
NOTE.
After the completed manuscript was in our hands, we asked the author to prepare this appendix. It is not a part of the general plan of the book, but is placed here, at our request, as a
brief treatise for reference only.
THE PUBLISHERS.
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APPENDIX
INJURIOUS INSECTS, AND MODES OF DEALING WITH
THEM
( For reference. ) FARM PRACTICES. CULTURE
Whenever an insect appears in injurious numbers it becomes highly essential that a knowledge of its life history should be acquired. In the life of many insects there is a stage where methods of culture or farm practices will destroy the insects and prevent the possibility of damage from them or from their direct offspring. As illustrations, in alfalfa-growing regions, native grasshoppers lay their eggs in the alfalfa-field late in the fall of the year. These eggs hatch in the early spring and the young defoliate the alfalfa. They mature during the summer and lay eggs on the same ground. These will destroy the next year's alfalfa yield. If the alfalfa lands are thoroughly harrowed in the early spring with a disk hamnv, the egg-pods are turned out of the ground and become a prey to birds and other insects. The exposure to sun and rain and the sudden changes in temperature destroy any which escape the birds and insects. The disking, likewise, materially increases the alfalfa yield.
The Hessian fly seems to have but one vulnerable point in its life; that is the time from wheat harvest until wheat sowing. The females of the earl}' fall brood seem to be so timed that they lay all their eggs
(301)
302
ELEMENTABY STUDIES IN INSECT LIFE
before the last of September. Now, if the summer volunteer wheat is kept under, and wheat, rye and barley sowing is postponed until after the middle of September, it is evident that, since the Hessian fly can live only on these cereals, the young of the fall brood will not find proper nourishment.
Clean culture is everywhere and at all times to be commended, since rubbish of any kind and all kinds offers a refuge for the hibernation of insects, and weeds furnish nourishment for the growing insects. The fol- lowing illustrates the point: crab-grass had been al- lowed to grow undisturbed through the summer in a young pear orchard. The crab-grass was plowed under in October. The leaf-eating insects, driven from the crab-grass, defoliated the young pear trees. These be- gan to bud again, when a heavy frost occurred, biting the tender buds and killing many of the trees.
Preventives. — Clean, thorough culture. Bands of cotton are placed around the bases of trees, then cov- ered with tar or similar harmless adhesive substances. This is done to prevent the ascent of climbing cut- worms, canker-worms, or the wingless female parent of the canker-worm. Ditching, with occasional post- holes in the ditch, for army-worms and chinch-bugs. (See page 136.)
Rotation of Crops. — Crop rotation is very effective. The corn-root worm rarely effects serious damage until land has been planted in corn at least three years suc- cessively. As before stated, the best means of preven- tion is thorough and clean culture. When insects be- come destructive they should be reckoned as a factor in deciding proper modes of cultivation.
INJTTRlOtJS INSECTS
303
Insecticides. — In dealing witli insects directly, we Lave three classes to combat:
1. Those with biting month-parts, having jaws, and masticating their food.
2. Those with sucking month-parts, having a beak, through which fluid nourishment is taken.
3. Insects of either of the above classes., but inac- cessible, such as insects on roots of trees or in bins of grain.
For Insects that Chew their Food. —
ARSENITES. — Since the first class bite off portions of their food, it is evident that poisonous substances placed thereon will be taken into the digestive system with the food.
SPRAYS.— -Paris green, an aceto-arsenite of copper, contains, when pure, about 58% of arsenic. The amount of arsenic contained is variable. An average analysis is: arsenic, 47.68%; copper oxide, 27.47%; sulphuric acid, 7.16%; moisture, 1.35%; insoluble material, 2.32%. In water, Paris green is practically insoluble. The spray formula generally used is Paris green one pound, freshly slaked lime two pounds, and 150 gallons of water. The addition of the lime is to prevent any caustic injury to the foliage. This for- mula varies somewhat with the plants sprayed. It can be used upon potatoes, apple trees, and most species of shade trees. For stone fruits the amount of water should be doubled, since leaves such as peach leaves are easily injured by arsenites. This spray when being used must be kept in a constant state of agitation, or the poison will settle. The liquid at the bottom of the
304
ELEMENTARY STUDIES IN INSECT LIFE
tank will be so strong as to injure the foliage, while that at the top will be useless. (See requisites for a spraying-pump. )
FIG. 231. The "Pomona" spray-pump, mounted on end of barrel. Used to spray with arsenical mixtures.
LONDON PURPLE.— - This is a by-product in the manu- facture of aniline dyes. It is an arsenite of lime, and contains a variable amount of arsenic. The average may be considered from 30% to 50% arsenic. It is a finer powder than Paris green, likely to remain longer
INJURIOUS INSECTS
305
in suspension. It sometimes contains much soluble arsenic, however; hence, is more liable to burn the fo- liage. Its use in spraying is the same as Paris green, with the exception that it is advisable to add greater amount of lime.
BAIT.— -Paris green or London purple 1 ounce, chopped grass or clover 8 ounces, and enough syrup to permit the mass to be worked into balls. These balls are spread around gardens for wire-worms, beetles, crickets, katydids, etc. For grasshoppers and cut- worms, mix 40 pounds bran, 15 pounds middlings, ar- senic 20 pounds, cheap grade of syrup 2 gallons. Mix in soft water to a paste.
For Insects with Sucking Mouth-parts.—
KEROSENE EMULSION.— - It is evident that such in- sects will not imbibe sufficient arsenic placed on a leaf, under the cuticle of which the sucking insects are with- drawing plant juices, to poison them. These insects are destroyed by contact poisons or external irritants, such as kerosene emulsion ; a spray composed of soft water 1 gallon, hard soap ? pound. The soap is dis- solved in the water by shaving and then boiling with the water. Remove from fire and add 2 gallons of kerosene ; mix thoroughly, add 30 gallons of soft water and apply with kerosene emulsion spraying-pump. To kill, this must reach the bodies of the insects. The substance is penetrating, and enters the breathing-tubes through spiracles of the body, interfering with respira- tion, and finally choking the insect.
Crude petroleum, applied with emulsion spraying- pump during winter months when leaf buds are closed —20
306
ELEMENTARY STUDIES IN INSECT LIFE
and fully dormant. For scale insects, sufficient should be applied to moisten bark of the tree. It is not safe to apply in excess, since there is a liability of injuring the tree. This substance should never be used during the growing season.
Fio. 232. " Kerowater " spray-pump. Designed for mechanically mixing and spraying kerosene and water. The oil and water are mixed and discharged in a milk-like emulsion.
Inaccessible Insects. — Carbon bisulphide, a very vola- tile and highly inflammable liquid. The vapor is very destructive to animal life. The vapor, being heavier than air, is effective against root insects and insects
INJURIOUS INSECTS
307
in stored grains. For root insects it is poured into holes, which are immediately closed up, causing the fumes to permeate the soil in all directions. For in- sects in grain bins, pans of this liquid are placed <m the tup of the grain or stored material. The vapor descends through the stored material. About a tea- spoonful is required for each cubic foot of space. Lighted lamps, fire, lighted pipes or cigars must be kept from the building while this method of fumiga- tion is in progress.
BORDEAUX MIXTURE.— - This is primarily a fungi- cide, but has likewise insecticide qualities in certain cases. It is frequently used to good effect at the same time with arsenical sprays for apple scab and other fungous diseases. Paris green is much more prefer- able in composition with the Bordeaux mixture. The formula fur the Bordeaux mixture is as follows:
Sulphate of copper 6 Ibs.
Quicklime 4- Ibs.
Water 40 gals.
Dissolve the copper sulphate in 4- gallons of water;1 slake the lime in another vessel; add the milk of lime slowly to the copper sulphate, stirring constantly. Strain through a sieve or coarse-grained guimysack, and add the remainder of the water. The mixture is ready for use. A simple test to make sure that enough lime is present in the mixture to properly protect, the plant, is to place some bright metal substance, such as a knife-blade, in the Bordeaux mixture. If when the blade is withdrawn there is an appearance of copper
1 The best way to dissolve the sulphate of copper is to suspend it la the water by means of a bag of coffee-sacking. Use the pulverized sulphate.
308
ELEMENTARY STUDIES IN INSECT LIFE
on the blade, more lime should lu> added until the knife- blade can be withdrawn untainted. Bordeaux mixture
FIG. 233. Seneca spray-nozzle, giving fan-shaped spray covering considerable area, and throwing coarse spray. Adapted to throwing spray some distance.
when used with Paris green solution can be used as so much water; that is, if the amount of water required in mixing up the Paris green solution is 150 gallons, pour in the 40 gallons of Bordeaux mixture and then add the balance or 110 gallons of water, making the 150 gallons of solution of Paris green.
FIG. 234. Vermorel spray-nozzle, affording a conical discharge and fine spray or mist. Adapted to spraying of trees, etc., at close range.
SPRAYING MACHINERY.— - To secure satisfactory re- sults in spraying, the spray must be kept agitated while being applied, and the application of the spray, as its name implies, should be as a fine mist. The agita-
INJURIOUS INSECTS
tion of the material is dependent upon the mechanism of the pump, the formation of the proper spray or mist upon the nozzle, and the force of the pump. The tank or receptacle for the liquid insecticide can conform to requirements. It may be a small bucket, a barrel, or a tank 011 wheels.
INJURIOUS INSECTS.
Ants. — (Formica sp., order Ilymenoptera.) Insects frequenting- pantries during summer months. Locate crevice from which they come, pour in carbon bisul- fide. Ant-hills in lawns can be destroyed by use of same substance poured into holes made in the ant-hill.
Aphids, — Plant-Lice, — Green-Fly. — Order Hemiptera. Minute insects feeding upon tender parts of plants grown both indoors and outdoors.
Remedies.— - Kerosene emulsion; tobacco water. In greenhouses, fumigation with smoke from burning to- bacco stems.
Apple. — APPLE-TREE BOKEL;, HOUND-HEADED. — (/>V perda Candida Fabr. ; order Coleoptera.) In the fall the bark of infested young trees discolors near the base of the trunk. The larva lies beneath this discoloration. In the spring the barjc cracks, and reddish wood dust drops. The adult is a pale-brown beetle, with two creamy white stripes the full length of the body. The antemur are longer than the body. The egirs are laid in June and -Inly. The larva spends the season in the trunk of the tree, boring during the summer months. The full-grown larva is over an inch long, fleshy, foot- less, and has a chestnut-brown head.
Preventive.— -Heavy coat of whitewash on trunks in
310 ELEMENTARY STUDIES IN INSECT LIFE
latter part of May. Wrapper of mosquito netting around the lower portion (about two feet high) of trunk, tied at the top and hilled up against at the bot- tom. Whitewash upper part of trunk.
Remedy.— -Dig out borers with a sharp knife and strong wire probe.
APPLE-TREE BORER, FLAT-HEADED. — -(Chrysobothris femorata Fabr. ; order Coleoptera. A shining green- ish black beetle, a little less than half an inch long. The larva can be found in trunk and larger branches. May be detected by discolored spots, cracking of bark, or appearance of sawdust. Mature larva, pale yellow, head end greatly enlarged and flattened.
Preventive and Remedy. — Same as for Round- headed borer.
APPLE FLEA BEETLE. — (Graptodera foliucca Lee.; order Coleoptera.) Beetle one-fifth inch long, feeding upon leaves.
Heinedy. — Arsenites.
BARK-LICE (especially Mytilqspis sp., Aspldlotus sp., Chionaspis sp. ; order Hemiptera). Mite-like insects, crawling in early spring; later becoming stationary, and secreting a waxy scale. (See page 1ST.)
Preventive.— -Plant unaffected trees.
Rem-edij. — Spray with kerosene emulsion during growing season ; with crude petroleum during dormant season.
BUD MOTH. — ( Tmetoeera ocellana Fabr. ; order Lepidoptera.) A minute moth, the larvtr of which de- stroy the flower-buds of apples, pears, plums, etc.
Remedy. — Arsenite sprays applied as buds begin to open, and then ten days later.
INJURIOUS INSECTS
311
TANKER WORM. — (Paleacrita rcrnald Peek. ; order Lepidoptera.) The "measuring-worm" larva, about an inch long, feeds upon the leaves. When disturbed it suspends itself by a thread.
Preventive.— ribands smeared with tar, printers' ink, or a similar harmless adhesive substance, placed around the trunks of the trees, about first of February, to pr&- vent the ascent of wingless parent female.
Remedy. — Thorough spraying with arsenites; very effective.
CODLING MOTH. — ( < 'tiri>oc<if^a ponwnclla Linn.; order Lepidoptera.) The larva a whitish worm, found feeding in or toward the core of the apple. Generally two broods. For adult, see Fig. 104.
Remedies. — Thorough spraying with arsenites, when blossoms have fallen ; then again ten days later. See pages 129, 131. Can be used profitably with Bordeaux mixture for apple scab. Two broods. Larvae and chrysalids will secrete themselves in burlap, cloth or paper bands in forks of trees, or around trunk. These can be destroyed every seven to nine days.
FALL WEB WORM. — (Hyphaniria cunca Drury ; or- der Lepidoptera.) A hairy caterpillar varying in color from gray to pale yellow or bluish black. It feeds upon the leaves of many trees, and lives in wyebs.
Remedies.— -Remove the webs; crush, or burn occu- pants. Spray with arsenites.
ROOT LOUSE. — (Schizoneura lanigera Hausm. ; or- der Hemiptera.) A small insect whose presence on the root is manifested by knotty swellings of roots and the presence of bluish white " wool." In another form
312 ELEMENTARY STUDIES IN INSECT LIFE
the insect feeds upon the branches. The woolly white covering is present here also.
Preventive.— -Plant unaffected trees.
Remedies.— -Hot water. Roots of nursery stock may be dipped in water having a temperature of 120° to 150° F. Kerosene emulsion or tobacco-dust poured in trenches around the roots of orchard trees.
TENT CATERPILLARS. — ( Clisiocampa Americana Harris; order Lepidoptera.) Hairy blackish larva? about two inches in length, white stripe along back, feeding on the leaves in May and June, emerging from silken webs or tents in which they spend the time not occupied in feeding.
Remedies. — Cut off egg-covered twigs during winter and early spring. Burn out or remove nests. Spray with arsenites.
TUSSOCK MOTH. - - ( Orgy la leucostigma Sm. and Abb. ; order Lepidoptera.) A bright yellow caterpillar, with red markings about an inch long; very hairy.
Remedies. — Collect foamy egg-masses in fall. Spray with arsenites.
Apricot.-- PIN -HOLE BORER. — ( tfcolytus rugulosus Ratz. ; order Colcoptera.) See under Peach.
PLUM CURCULIO. See under Plum.
Bean. — BEAN WEEVIL OR BEAN BUG. — (B ruckus oi- ler fits Say; order Coleoptera.) Very similar to pea weevil. A small brown-black beetle. The beetles ap- pear in fall and spring, and lay eggs in young pods. The larva- or grubs live in growing seeds.
ReinriUcs. — As soon as mature beans are picked, place them in temperature of 145° F. for an hour;
INJURIOUS INSECTS
313
this does not injure the seed. The beans may also be placed in tight box or bin and fumigated with carbon bisulphide.
BAG WORM OR BASKET WORM. — (Tliyridopteryx ephemerae formis Haw.; order Lepidoptera.) The bags covered with short bits of sticks, empty or containing the female egg-sac, conspicuous during winter months. The larva feeds upon both evergreen and deciduous trees.
Remedies. — Arsenites. Hand-picking.
BARK-LICE. See under Apple.
Blackberry. — CANE BORER. — (Obcrea bimaculata Oliv. ; order Coleoptera.) Small slender black beetle. It makes two girdles, an inch apart, near the tip of a cane, and lays egg between girdles. The larva bores down the cane.
Remedy. — When cane-tip wilts, cut off below lower girdle, and burn.
ROOTGALL-FLY. — (Rhodites rod leu in Sacken; order Diptera.) The small larva causes galls on roots of blackberry, raspberry, and rose. The bush appears sickly. Female dies. Do not confound with true root- galls.
Remedy. — Dig up and burn badly affected plants.
SNOWY TREE CRICKET. — (Oecantlius niveus Serv. ; order Orthoptera.) Small whitish insect; cricket-like. Punctures canes to deposit eggs. (See Figure 36.)
Remedy. — Burn infested canes in winter or very early spring.
BLISTER BEETLE. — (Family Meloidse; order Cole- optera. ) Soft, slim, long-necked beetles ; some black
314 ELEMENTARY STUDIES IN INSECT LIFE
and others gray or striped. Feeds upon leaves of trees and many garden plants.
Remedy. — Arsenites.
BUFFALO .Morn. --Buffalo Beetle. (Aii/Jtroni* scrof- ula rice Linn.; order Coleoptera.) The adult is a small brick-red and white beetle, about one-quarter inch long. The larva: are small, dark-colored, hairy creatures, in- festing carpets and woolen goods. The larva do the damage.
Remedies. — Use rugs instead of carpets. Rugs to be sunned frequently. Infested carpets should be treated likewise. The floors under them should be thoroughly scalded. Infested woolen may be placed in tight boxes and fumigated with carbon bisulphide.
Cabbage. — CABBAGE WORM or CABBAGE BUTTERFLY. (Picris rapes Linn.; order Lepidoptera.) Larvae an inch long, green, black and yellow markings. Feeds upon the leaves and heads. Two broods.
Remedies. — Hot-water spray at temperature 140° to 160° F. Kerosene emulsion. Salt water sprinkled into
the head.
GREEN LETTUCE WORM. — (Pluxia- brassicce Riley ; order Lepidoptera.) Pale green larva over an inch long, faint stripes. Feeds upon leaves of many plants, such as celery, cabbage, and lettuce.
Remedies.- - Kerosene emulsion. Hot water.
HARLEQUIN CABBAGE BUG. — ( Miiir/antia hixirion- ica Halm.; order Hemiptera.) Bug about half-inch long, orange dots and stripes over blue-black ground ; somewhat gaudy. Two to feix broods.
Remedies. — Hand-picking. Insects will secrete them-
INJURIOUS IXSKCTS
selves in piles of rubbish. In fall, place [tiles <>f rubbish in patch; burn early in the winter.
LICE. — (Family Aphida-; order Ilemiptera.)
Remedy. — Kerosene emulsion.
MAGGOT. — (PJiorbla braxxicce Bouche; order Dip- tera.) The maggot, a fly larva, eats its way into the crown and roots of young; cabbage, cauliflower, rad- ishes, etc.
Remedies.— -For cabbage and cauliflower, pour tea- spoonful carbon bisulphide in bole close to roots of each plant. Burn all infested plants.
The "club-root" of cabbage is not due to this, but is a fungous disease.
Cauliflower. — ( CAULIFLOWER OR CABBAGE WORM. See under Cabbage.
MAGGOT. . See under Cabbage.
Celery. — GREEN LETTUCE WORM. See under Cab- bage.
Cherry — CANKER WORM. See under Apple.
PLUM CURCULIO. See under 1'luin.
CHINCH-BUG. See under ( 1orn.
CLOTHES MOTH.—- ( Tinea pellionella Linn. ; order Lepidoptera.) Small cylindrical .rolls or cases, in cadi of which is a small, soft-bodied larva. This feeds on woolens, hair-cloth, fur, and feathers. The adult is a very small light-brown moth; wing expanse about one- third of an inch. (See Fig. 120.)
Preventive. — After thorough cleansing, airing, sun- ning of woolens, furs, etc., through May and June.
316 ELEMENTARY STUDIES IN INSECT LIFE
pack away for summer wrapped in stout paper, to pre- vent entrance of some belated female.
Remedies.- - Thorough sunning of goods likely to be infested in May and June. Goods which can be readily placed in tight chests can be fumigated with carbon bisulphide.
Corn. — CHINCH-BUG. — (Blissus leucopterus Say; or- der Hemiptera.) A small dark-colored bug; wings white, with dark triangular spot on each. The bugs frequently collect on corn-stalks and leaves so as to blacken a part of the plants. They frequently obtain their first spring food in wheat, millet, and other cereals, forsaking them for the corn after the other cereals are harvested.
Preventive.— -Burning all rubbish in fall. Rotation
of crops.
Remedy.— -Ditching. (See Fig. 109.)-
CORN-ROOT WORM. — (Diabrotica loiifjicornis and D. 12-punctata; order Coleoptera.) Stalks of corn stunted; fall over easily. Examination shows many roots sev- ered. Plain greenish-brown beetles, and yellowish bee- tles with twelve black spots on back; to be found in the shooting tassels.
Preventive. — Rotation of crops.
CORN BILL-BUGS.— (Splienoplionis sp. ; order Cole- optera.) Black or brown in color; one-fourth to one- half inch in length ; back marked with longitudinal ridges. Adults attack corn planted after timothy or sod, hiding during day at base of corn plants, boring round holes in stem.
Remedy.— - Fall plowing of land.
INJURIOUS INSECTS
317
GRAIN BEETLE OR GRAIN WEEVIL. — (Silraiius suri- namensis Linn; order Coleoptera.) Reddish brown beetle about one-tenth of an inch in length; feeds in stored corn or other grain.
Remedy.— -bisulphide of carbon.
ANGOUMOIS GRAIN MOTH. — ( Gdecliia- cereal ell a- Oliv. ; order Lepidoptera. ) The larva burrows within kernels of stored grain, making small round hole. See Figure 108.
Remedy. — Carbon bisulphide.
CORN WORM. — See under Tomato.
CORN-ROOT LOUSE. — (Aphis maidi-radicis Forbes; order Hemiptera.) Masses of small bluish lice found feeding on roots of corn plants.
Remedy.— - Thorough spring culture to keep down weeds upon which lice can also live, and to encourage the more vigorous growth of the corn.
GRASSHOPPERS. — (Family Acridida?; order Orthop- tera. ) For description, see pages 3-12.
Pre ven tive.— -Disk-harrowing in early spring, where grasshoppers deposit their eggs the fall before.
Remedies. — Arsenites in bait. When grasshoppers are entering a new field, a strip of the field at the place of entrance may be sprayed with arsenites, to be fed upon as they enter. Catching with " hopperdozer."
Cucumber. — CUCUMBER OR PICKLE WORM. — (Eudi- optis nitidalis Cram.; order Lepidoptera.) Larva about an inch long, yellowish white, slightly green, boring into cucumber. There are two broods.
Remedies.— -Hand-picking when they first appear. Infested fruit to be destroyed.
318 ELEMENTARY STUDIES IN INSECT LIFE
MELON WOEM. — (Eudioptis Jiyalinata Linn. ; order Lepidoptera.) Larva about an inch long, slightly hairy, yellowish green. Feeds on melon leaves and eats holes into the melon, cucumber, and squash. Two broods at least.
Remedies. — Arsenites applied very early in the sea- son.
SPOTTED CUCUMBER BEETLE. — (Diabrotica 12-punc- Intn Oliv. ; order Coleoptera.) Yellow and black spot- ted beetle, one-fourth inch long; feeds on leaves and fruit. The larva sometimes injures corn root. (See Corn.)
Preventive. — Cover with frames of mosquito net- ting.
Re mcdy.— -Tobacco powder liberally applied. Ar- senites in flour. Ashes sprinkled on plants from two to three times when they are wet.
STRIPED CUCUMBER BEETLE. — ( Dialrolica vittata Fabr. ; order Coleoptera.) The larva of beetle with black stripes about one-fourth inch long. The beetle feeds on the leaves; the larva, about one-eighth inch long, feeds on roots. There are two broods.
Preventives and remedies same as for Spotted Beetle.
Currant. — BORER. — (Scsia tipuliformis Linn.; order Lepidoptera.) Whitish larva, which bores into cur- rant canes and into gooseberry, spending winter there.
Remedy.— -Burn all affected cane in fall and early spring. Infested canes are made manifest by lack of vigor and stiffness.
CURRANT SAW-FLY. — (Nemahts ventricosus King; order Hymenoptera.) A yellowish green larva, about three-fourths inch long, and feeds upon the leaves. Two to four broods.
INJURIOUS INSECTS
Remedies. — Arsenites thoroughly applied to check first brood. Should be applied before larva* leave the lowest leaves. Later broods are more difficult to deal with ; hence, the first brood .should lie promptly checked.
Carpets. — BUFFALO BEETLE. See under B.
CLOTHES MOTH. See under C.
CODLING MOTH. See under Apple.
Clover. — CLOVER HAY WORM. — ( Asopia costal i* Fabr. ; order Lepidoptera.) A larva which attacks the dry or partially dry clover.
Remedy. — Clean mows out before storing new hay ; salt the first two or three feet of newly stored hay.
CLOVER SEED MIDGE. — (Cecidoini/id leguminicola Lint.; order Diptera.) Larva feeds upon the forming- seed, destroying it.
Rented icx. — Cut early crop when in full head, and depend upon second crop for seed. The flies oviposit in flowers of first crop. Fall plowing in infested fields. Use lime and kainit in fall after crop is off.
CUT- WORMS. — (Agrotis sp. and others; order Lepi- doptera.) Soft brown to grayish worms feeding upon tops and crowns or even roots of plants.
Remedy. — Arsenical baits placed about in the even- ing. In garden plots, dig deep narrow holes near plants to be protected. The worms will fall in and cannot escape. Worms frequently remain hidden during the day.
CUT- WORMS, CLIMBING. — Several varieties. Worms climb trees at night and eat off the buds.
Preventive. — Cotton batting banded about the tree; top of band turned down, and worms cannot climb over.
320 ELEMENTARY STUDIES IN INSECT LIFE
Remedies. — Arsenical baits.
Elm. — CANKER WORM. See under Apple.
BAG WORM. See under B.
ELM -LEAF BEETLE. — (Oalleruca xanthomelcena Schr. ; order Coleoptera.) A small beetle that eats the green matter from elm leaves, giving the tree a scorched appearance.
Remedy. — Arsenites.
FOUR-STRIPED PLANT-BUG. — (Poecilocapsus lineatus Fabr. ; order Hemiptera.) Bright-yellow hug, with black stripes. It punctures the young leaves and shoots of a number of plants.
Remedy. — Kerosene emulsion.
Gooseberry. — CURRANT BORER. See under Currant.
FOUR-STRIPED PLANT-BUG. See under F.
GRAIN MOTH. See under Corn.
GRAIN WEEVIL. See under Corn.
Grape. — APPLE-TREE BORER. See under Apple.
CURCULIO. — (Craponius incequalis Say; order Cole- optera.) A small black or grayish larva; infests the grape in June and July. Discolors the berry around the little black hole of entrance.
Remedies. — Jar the beetle off in sheets, as with the plum curculio.
GRAPE SLUG OR SAW-FLY. — (Selandria vitis Harris; order Hymenoptera. ) Larva yellowish green; about one-half inch long; feeds upon the leaves. Two broods.
Remedies. — Arsenites.
GRAPEVINE FIDIA. — ( Fidia viticida Walsh; order
INJURIOUS INSECTS 321
Coleoptera.) A short, broad beetle; riddles the leaves in June and July. The larva attacks the roots of grapes -- preferably the Worclen.
Remedies. — Strong arsenic sprays for the beetles ; the larvas on roots can be destroyed by bisulphide of car- bon.
GRAPE FLEA-BEETLE. — (Graptodera clialybea Illig. ; order Coleoptera.) A blue metallic beetle, one-fourth inch in length. Feeds upon buds and tender shoots in spring.
Remedies. — Arsenites.
GRAPEVINE SPHINX. — (Ampelophaga myron Cramer; order Lepidoptera.) A large green caterpillar, with yellow spots and stripes. At maturity is about two inches in length. Bears a horn at the posterior extrem- ity, and feeds upon the leaves and young grapes. Two broods.
Remedies.— -Hand-picking. Arsenites to be used in the early season.
ROOT BORER. See Grapevine Fidia.
SNOWY CRICKET. See under Blackberry.
LEAF-HOPPER. — (Erythroneura vitis Harris; order Hemiptera.) A small insect, less than one-tenth inch in length. 'Feeds upon leaves, and makes them appear scorched.
Remedies.— -Kerosene emulsion; small bonfires built at night in vineyard attract many to them. Clean cul- ture in the fall, to prevent collection of rubbish for insects to hibernate in.
GREEN-FLY. See Plant-Lice.
GREEN STRIPED MAPLE WORM. — (Anisota rubicunda
Fabr. ; order Lepidoptera. ) A yellowish green, longi- —21
322 ELEMENTARY STUDIES IN INSECT LIFE
tudinally striped naked insect, about one and a half inches long. Feeds on leaves of maple. Two broods.
Remedies. — Spray with arsenites, early in the sea- son. Insect has several parasites which keep it in check. Many birds prey upon it.
House Plants. — See Plant-Lice, Scale Insects, and Ked Spider.
HESSIAN FLY. See under Wheat.
HORN - FLY OF CATTLE. — ( Hcematobia serrata E. Desv. ; order Diptera.) A small black fly, about one- sixth of an inch long, tinged with brown and gray. Characteristic habit is to cluster about the base of the horn.
Preventive. — Greasy substances, such as tallow or fish oil, will keep insects away from animals for several days. Spraying the animals with kerosene emulsion.
JUNE BUG. See May Beetle.
LEAF-CRUMPLER. — (Phycis indiginella Zeller; order Lepidoptera.) Brown larva, found within the folded leaves of the various kinds of plants.
Remedy. — Spray with arsenite before the larvae conceal themselves within the folded leaves. Gather the folded leaves after the larvse have pupated, and burn them.
Lettuce. — APHIS or GREEN -FLY. — A plant-louse
which thrives on lettuce growing under glass.
Preventive.— - Tobacco-dust thrown on leaves of plants when aphis first appears. A better method is to fumi- gate with tobacco.
GREEN LETTUCE WORM. See under Cabbage.
LICE. See under Plant-Lice.
323
INJURIOUS INSECTS
MAY BEETLK <>i; JUNE BUG. — (Lacltn<mt<-nm Frohl. ; order Coleoptera.) A large familiar brown beetle, frequently heard buzzing about lamps at night. Feeds upon leaves of several varieties of trees. The common white grub, found when turning the soil, is the larval stage of this beetle. This grub frequently dam- ages strawberries.
Ecini'dics. — Use arsenites for beetle, and grubby plots can be freed by plowing to expose the grubs to poultry and field birds. The hogs will likewise clear the ground. Do not plant strawberries in land where these grubs are abundant.
MEALY-BUGS. — (Dactylopius adonidum Linn.; order Hemiptera.) White scale insects, which feed upon greenhouse plants.
Remedies. — A small stream of water generally drives them away from greenhouse plants. House plants may be washed in soapsuds or the insects can be removed from tender plants with an old toothbrush.
Maple. — MAPLE WORM. See under Green Striped Maple Worm.
FALL WEB WORM. — (Hyphantria cunea Drury; order Lepidoptera.) Caterpillars feeding in swarms within large webs in late summer and early fall. Re- move the web-infested limbs, and burn or crush the worms thereon. If it is objectionable to remove the infested limbs, spray the populous web thoroughly with kerosene emulsion.
BOX-ELDER BUG. See page 18-i.
BAG WORM. See under B.
MAPLE SCALE. — (Pulvinarla innumerabilis ; order
324: ELEMENTARY STUDIES IN INSECT LIFE
Hemiptera.) A good-sized brown scale insect. During the summer months a large cottony egg-sac appears from the posterior end of the female.
Remedy. — Spray with crude petroleum, during the dormant season.
MOSQUITO. — (Family Culicida?; order Diptera.) A long, slender fly. The females have strong, piercing mouth-parts used in piercing the cuticle of man and other animals.
Preventive.— -Keep cisterns and rain-barrels well covered. The surface of all ponds and small pools of water in the vicinitv, when not drained, should be
J 7
coated during the breeding season with kerosene, since these insects breed in rain-water.
Pea. — PEA WEEVIL. — (Bruchus pisi Linn.; order Coleoptera.) Very similar to Bean Weevil. See under B. Same remedies.
Peach. — -(Aphis pcrsicce Smith; order Hemiptera.) A dark-brown plant-louse, attacking tops and roots. More abundant in sandy lands.
Remedies.— - Kerosene emulsion for tree colonies. Tobacco-dust placed in trench around roots of trees for root colonies.
FLAT-HEADED BORER. See under Apple.
FRUIT BARK BEETLE OR PIN-HOLE BORER. — (Scoly- tus rugulosus Ratz. ; order Coleoptera.) A black beetle which bores into trunks and branches of peach, plum and apricot trees. It is about one-tenth of an inch in length.
Remedies.— -Hum the affected trees, since this beetle shows preference for weak or sickly trees. Keep trees strong and healthy.
INJURIOUS INSECTS
325
PEACH-TREE BORER. — (Sannina exitiosa Say; order Lepidoptera.) Larva whitish, three-fourths inch long at maturity ; bores into crown and upper roots of peach, causing gum to exude.
Preventive.— -Mounding, i.e., mound up earth about a foot high around the tree early in the summer, and re- move late in fall. The moth, then, lays eggs at mound top, and the larva1 die from exposure. Only fairly sat- isfactory.
Remedi/.— -The most reliable means of combatting this insect is to dig out the borers in the late fall and early spring.
PLUM CURCULIO. See under Plum.
Pear. — APPLE-TREE BORER. See under Apple.
BUD MOTH. See under Apple.
CODLING MOTH. See under Apple.
FLAT-HEADED BORER. See under Apple.
PEAR-LEAF BLISTER. — (Phytoptus />//>•! Scheuten.) A very small mite, causing blisters on the leaves. The mites spend the winter under the bud scales.
Remedy. — Spray with kerosene emulsion.
PEAR-TREE BORER. — (Sesia pyri Harris ; order Lepi- doptera.) Larva whitish ; feeds under bark.
Remedy.— -Dig out the larva with a knife.
PSYLLA. — (PsylJa pyricola Forst. ; order Hemiptera.) Besembles plant-louse ; infests pear twigs when fruit is setting. Exudes " honeydew >: in which grows a fungus. This fungus frequently gives the pear twigs a sooty appearance.
Remedi/.— -Repeated sprayings with kerosene emul- sion, beginning at time leaves are expanding.
HOUND-HEADED BORER. See under Apple.
326 ELEMENTARY STUDIES IN INSECT LIFE
Plum. — BUD MOTH. See under Apple.
CANKER WORM. See under Apple.
CURCULIO. — ( C onotrachelus nenuphar Herbst. ; or- der Coleoptera.) The larva is a whitish grub, which feeds on the fruit.
Remedies. — Jar the trees with padded mallet, in the early morning, beginning when the trees are in bloom and continuing four or five weeks. Place sheets under the tree, to catch the beetles as they fall; gather and destroy. The sheet or canvas may be arranged upon a frame in the form of an inverted umbrella, with one section left out to admit the tree; and this structure may be pushed around from tree to tree on wheels.
FLAT-HEADED BORER. See under Apple.
PLUM-GOUGER. — (Coccotorus scutcllaris Lee.; order Coleoptera.) The larva feeds on the kernel. The beetle bores a round hole in the plum. The curculio makes a crescent mark.
Remedy. — Same as for Curculio.
PLUM SCALE. — (Lecanium sp. ; order Hemiptera.) A large brown scale insect.
Remedy. — Spray with kerosene emulsion, or in win- ter months with crude petroleum.
Potato. --COLORADO POTATO BEETLE. — (Dorypliora decemlineata Say; order Coleoptera.) Both beetle and larva feed upon the leaves.
Remedies. — Arsenites.
STALK WEEVIL. — (Tricliol>aris trinotata Say; order Coleoptera.) The larva bores into the stalk of the po- tato near the ground.
Remedy.— - Burn all infested vines.
INJURIOUS INSECTS
327
Quince. — ROUND-HEADED BORER. See under Apple.
Raspberry. — CANE BORER. See under Blackberry.
ROOT BORER. See under Grape.
ROOTGALL-FLY. — (Rliodites radlcum Sacken ; order Diptera. ) The larva produces galls on the roots of the raspberry, blackberry, seriously affecting the health of the plant. These swellings must not be confounded with the true root-galls found on raspberry, blackberry, apple, and peach. This root-gall is a fungous disease, espe- cially noticeable in nursery stock.
Remedy. — The best remedy thus far seems to be the destruction of all infested plants.
SNOWY TREE CRICKET. See under Blackberry.
RED SPIDER. — (Tetranychus telarius Linn.) A small red mite, found on plants both in greenhouse and out- doors.
Remedy. — Strong streams of water from a hose, kerosene emulsion.
Rose.— -ROOTGALL FLY. See under Raspberry.
MEALY-BUG. See under M.
ROSE SLUG. — (Selandria rosce Ilarr. ; order Hymen- optera.) A slug-like worm, soft greenish or yellowish, about one-half an inch long. It eats large patches in the upper surface of rose leaves. The leaves appear scorched, and drop off. Feeding is done by night, and the slugs rest on the under side of the leaves during the day.
Remedy.— - Forcible stream from a hose will wash off many. Spray with arsenites.
SAN JOSE SCALE. — (Aspldinhix pernidosus fWnst. ;
328 ELEMENTARY STUDIES IN INSECT LIFE
order Hemiptera.) The very small circular scale not easily detected; lives upon a large number of decid- uous trees.
Remedies. — Frequent applications of kerosene emul- sion during summer. Several applications of crude petroleum during the dormant season. Avoid infested stock.
SCALE INSECTS. See under Plant-Lice.
Squash. — BORER. — (Melittia ceto Westw. ; order Lepidoptera.) The larva bores into the root or crown of the squash and other plants of this family. The parent moth flies by day.
Remedies. — When vines begin to run, cover the fourth, fifth or sixth 'joints with earth, so that they may take root and aid in supporting the plant.
SQUASH BUG. — (Anasa tnstis De Geer; order Hem- iptera.) A flattened, rusty, ill-smelling bug, one-half inch long ; pierces leaves with its sucking beak. Leaves become yellow and die.
Remedies. — The insects will collect at night under boards laid near the hills, and can be crushed. A thor- ough spray with kerosene emulsion will kill the young bugs.
Strawberry. — CROWN BORER. — (Tyloderma fragance Riley; order Coleoptera.) A white grub; bores into the crown of the plant during the middle of summer.
Remedy. — Burn over field after fruit is gathered. If this is unsuccessful, dig up plants and burn them.
MAY BEETLE. See under M.
LEAF ROLLER. — (Phoxopteris comptana Frohl. ; order Coleoptera.) Larva about one-half inch long; feeds on
INJURIOUS INSECTS
the leaves, protecting itself by rolling them up and tying with threads of silk. Two broods.
Remedies. — If arsenites are applied before the leaves are rolled, the caterpillar may be destroyed; if not, after fruit is off the leaves of the strawberry plants should be mowed over, and the stalks and leaves burned.
ROOT BORER. — ( Anarsia lineatella Zeller; order Lepidoptera.) A whitish borer, boring into crown of plant late in season and remaining there over winter.
Remedy.— -Burn the plants.
ROOT LOUSE. — (J />///* Forbesii Weed; order Ilem- iptera.) In the latter part of the season lice appear in great numbers on the crowns and roots of the plants.
Remedies.— -Rotation of crops.
SAW-F.LY. — (Empliytus maculata Norton; order Hymenoptera.) A greenish larva, about three-fourths of an inch long; feeds upon leaves. Two broods.
Remedies. — Spraying with arsenites for second brood.
Sweet Potato. — SAW-FLY. — (Schizocerus chants Nor- ton; order Hymenoptera.) A small larva, which feeds upon the leaves.
Remedies. — Spray with arsenites.
Tomato.— - FRUIT WORM. — (Heliothis armiger Hub.; order Lepidoptera.) A pale-green or brown larva, about an inch long; faintly striped. Feeds upon the tomato fruit. The same species is found feeding in the head of the ears of sweet corn. Also attacks cotton.
Remedy.— - Hand-picking.
TOMATO WORM. — (Phlegethontius celeus Hbn. ; or- der Lepidoptera.) This large green worm is occasion- ally seen upon the leaves and stems of the tomato. By
330 ELEMENTARY STUDIES IN INSECT LIFE
reason of its size it is an attractive prey for parasites, and seldom bec'omes abundant enough to become serious.
Remedies— - Hand-picking. Arsenites.
Wheat. — CHINCH-BUG. See under Corn.
HESSIAN FLY. — (Cecidomyia destructor Say; order Diptera.) During the winter, small brown seed-pods ("flax-seeds") may be found in the plants near the roots. These are the chrysalids. Small black two- winged flies emerge from these in April and May. The young whitish grubs attack the stalks near the base. From two to four broods. The fall brood lays its eggs before the 20th of September. It attacks rye and barley.
Remedy. — Burn or plow under stubble immediately after harvest, and destroy summer brood which is then in " flax-seed " stage. Keep down the volunteer wheat ; postpone sowing the wheat, until after the 20th of Sep- tember, when eggs will have been deposited on other plants. Fertilizers added in spring materially aid in- fected wheat to tiller, and thus outgrow the injury.
FALL ARMY WORM. — (Laphygma frugiperda Smith and Abb.; order Lepidoptera.) A pale-brown cater- pillar ; feeds upon wheat, corn, rye, and other suc- culent plants, during September and October. Fre- quently travel together in the same direction in quest of food, — whence the name.
Remedy. — Late fall plowing of fields where pests have been ; crushing caterpillars with the roller. Wheat- fields eaten off in fall are not necessarily destroyed.
GRASSHOPPER. See under Corn.
WHITE ANTS or TERMITES.— - These insects frequent
INJURIOUS INSECTS
331
orchards, especially those containing old stumps or rub- bish. More common in Southern States.
Remedy. — Carbon bisulphide. Washing trunk of in- fested tree with a mixture of kerosene emulsion and arsenites.
WIRE WORM. — (Family Elateridce.) These are slim, brown larva1, which feed upon the roots of various plants. They are the immature forms of the " click beetle."
Remedy. — Arsenical bait of fresh clover or sweet- ened corn-meal dough. Fall plowing. Rotation of crops.
332 ELEMENTARY STUDIES IN INSECT LIFE
REFERENCE BOOKS.
PROTECTIVE DEVICES.
Animal Coloration. Beddard. London. 1892. The Colors of Animals (International Science Series). Poulton. London. 1890.
SOCIAL AND SOLITARY INSECTS.
The Solitary Wasps. G. W. and E. G. Peckham. Wisconsin
Geological Survey. Madison, Wisconsin. Ants, Bees and Wasps (International Science Series). J. Lub-
bock. D. Appleton & Company. New York. Langstroth on the Honey-Bee, revised by Dadant. Charles Dadant
& Son. Hamilton, Illinois. Harvesting-Ants and Trap-door Spiders, with Supplement. J. T.
Moggridge. L. Reeve & Company. 5 Henrietta Street, Covent
Garden, London.
FLOWERS AND INSECTS.
Fertilization of Flowers. Hermann Muller, translated by D. W.
Thompson. Macmillan & Company. London. 1883. The Natural History of Plants, Vol. II, Part I. Kerner and
Oliver. Henry Holt & Company. New York. 1895.
OUR FRIENDS AND FOES.
Economic Entomology. John B. Smith. J. B. Lippincott & Com- pany. Philadelphia. 1896.
Our Common Insects. A. S. Packard. Estes & Lauriat. Boston.
Bulletins and Reports of Division of Entomology, Department of Agriculture. Washington, D. C.
Mosquitoes. L. O. Howard. McClure, Phillips & Co. New York.
WEALTH OF INSECT LIFE.
Manual for the Study of Insects. J. H. and A. B. Comstock,
Comstock Publishing Co. Ithaca, N. Y. 1895. Insect Life. J. H. Comstock. D. Appleton & Company. New
York. 1897. The Insect Book. L. O. Howard. Doubleday, McClure & Co.
New York. The Cambridge Natural History. Vols. V and VI. Macmillan &
Company. London and New York. 1895. The Riverside Natural History. Vol. II. Houghton, Mifflin &
Company. New York and Boston. An enumeration of the published synopses, catalogues, and lists
of North American Insects. C. V. Riley. U. S. Department
of Agriculture, Division of Entomology, Bulletin No. 19. 1888.
INDEX AND GLOSSARY.
Abdomen of grasshopper, 266- 269.
Acquisition of insect forms, 222; of laboratory material, 239.
Acrididse, 182, 285. Acridiiiije, 182. Actifts limn, 194. JEschninre, 240. Agrioninae, 240. A</i-»tin sp., 319. Alaus oculatus, 190. Alfalfa blossom, fertilization of, 104-107.
Ammopltilti Yarrowi, 66-71, 91, 93.
Amoeba, 34.
Ampelophaga myron, 321. Anosia plcxippus, 40, 58 ; larva
and pupa of, 58; protective
characteristics of, 59.
.\tnisa tristis, 143, 328. Angmunois grain moth, 135, 317.
A»isc>i>l<'rt/x pometaria, 124.
AniNotti ntlticunda, 321.
.1 nnplilJialni UK, 42.
" Ant cows," 8.3.
Ants, 291,309; number of facets in compound eye of, 41; life history of, 81-85; the habits of, 247-9 ; modes of observing, 247-9; attending aphids, 185; mud house of, 83.
Antenna1, uses of, 36, 37, 38 ; of grasshopper, 257 ; of mos- quito, as auditory organs, 44; of eecropia moths, 39 ; varied forms in beetles, 289; in flies, 298.
Antenna 1 nerves, varied func- tions of, 42.
Anther, 96.
Aiithrcnus scroftilariae, 148, 314.
Anarxin Unratella, 329. Aphids, 309; cared for by ants, 83.
AphididsD, 294. Aphis Forbcsii, 329. Aphis maidi-radicis, 317. Aphis pcrsicac, 324. Apple flea beetle, 310.
Apple, insect enemies of, 309- 312.
Apple-tree borer, flat-headed, 310.
Apricot, insect enemies of, 312. Aptera, 165, 283, 284, 285. Arctiidae, 297. Army worm. 141, 142. Arnold, quotation of, 47. Arrangement of insects, 235. Arsenites, 303. Asclcpiodora ririilis, 108. Asilidse, 299. Asopia costatis, 319.
(333)
334
INDEX AND GLOSSARY
Aspidiotus ancylus, 189. grcenii, ISO. perniciosus, 327. Assassin-bugs, 292. Auditory organ, 266; location
of, 44.
Austral zone, 208. Australian ladybird in Califor- nia, 212.
Backswimmers, 293.
Bag- worm moth, 54, 313.
Bait, 305.
Bark-lice, 310, 313.
Barriers, 204 ; to advance of creeping insects, 130; to en- trance, 206; to existence, 200, 207.
Basilarchia arcliippus, 57, 60.
Basket worm, 313.
Bean, insect enemies of, 312.
Bean weevil, 312.
Bean-bug, 312.
Bees, 291; nurse, 78; influ- ence of, on alfalfa blossom, 107 ; on milkweed blossoms, 110.
Beeswax, secretion of, 78.
Bee-flies, 299.
Beetle, anatomy of, 276-279.
Belostomidae, 293.
Benacus griseus, 185.
Bibionidse, 298.
Bird-lice, 175, 287.
Blackberry, insect enemies of, 313.
Black swallowtail butterfly, the life of, 13-23; pupa of, show- ing protective resemblance, 50-53.
Blattidse, 178, 285.
Blissus leucopterus, 316.
Blister beetle, 288, 313.
" Blues and coppers," 294.
Bluebottle-fly, laboratory exer- cises on, 244, 245.
Bombardier beetle, 51, 53.
Bombiliidae, 299.
Bombus Howardi, 61.
Books of reference, 332.
Book-lice, 286, 287.
Bordeaux mixture, 307.
Boreal zone, 208.
Borer, 310, 327.
Brachynus americanus, 53.
Browning, quotation from, 15.
Breeding-cage, care of, 239 ; for Lepidoptera, 243.
Brush-footed butterfly, 294.
Bruchus obtectus, 312.
Bruchus pisi, 324.
Buffalo moths, 148, 149, 289, 314.
Buffalo beetle, 314. Buprestidse, 289. Butterfly, brush-footed, 294. Butterfly, classification of, 194.
California, Australian ladybird in, 212.
Calosoma scrutator, 277.
Camponotus pennsylvanicus, 84.
Canker worm, 124, 311.
Cane borer, 313.
Capsidse, 292.
Carabidse, 288.
Carbon bisulphide as an insecti- cide, 153, 306.
Carpocapsa pomonella, 125-131,
311.
Carrion beetles, 290. Carpet beetles, 289.
INDEX AND GLOSSARY
Carpets, insect enemies of, 319.
Caudal direction, 2.14.
Cauliflower, insect enemies of, 315.
Cabbage worm, insect enemies of, 314.
Cabbage butterfly, 294, 315.
Cabbage worm, 144, 314.
Cabinets, 234.
Caddis-flies, 176, 286, 287; larva of, 49.
Cecidomyia destructor, 330. leguminicola, 319.
Cecropia moth, 297; life history of, illustrated, 24-33.
Cercopidae, 294.
Celery, insect enemies of, 315.
Cephalic direction, 254.
Cerambycidce, 288.
Ceratopsyllus serraticeps, 197.
Cerci, of male grasshopper, 267 ; of female, 268.
Cicada, 185, 293; mode of pro- ducing sound, 45; mouth- parts of, 279-282.
Cicadidse, 293.
Cicindelidse, 288.
Circulatory system, 275.
Chafers, 288.
Chalcis-flies, 290.
Chalcididse, 290.
Chinch-bug, 135-137, 292, 316.
Chitine, 251.
Chrysalis, 2, 29.
Chrysididse, 290.
Chrysobothris femorata, 310.
Chrysomelidaa, 288.
Chrysopa, 48.
Claviger, 42.
Click beetles, 190, 289.
Clisiocampa americana, 123.
Clothes moth, 150-152, 296, .".15.
Clover, insect enemies of, 319. hay worm, 319. seed midge, 319.
Clypeus of grasshopper, 257.
Clytus marginicollis, 61.
Coccidse, 294.
Coccinella abdominalis, 133.
Coccinellida>, 289.
Cocoon, 28, 29.
Coccotorus scutellaris, 326.
Cockroach, 152, 153, 178, 285.
Codling moth, 125-131, 311.
Coleoptera, 189-191, 284, 287- 290.
Collecting at lights, 230.
Collembola, 166, 285.
Colony of bees, 73.
Colorado potato beetle, 326.
Complete metamorphosis, 2.
Compound eye, number of facets in, 41.
Comstock, on wing venation, 295; quotation from. 81 ; ex- periments with carpenter ant, 84.
Conotrachelus nenuphar, 326.
Cope, quotation from, 94.
Coreidsc, 292.
Corn, insect enemies of, 31(i.
Corn bill-bugs, 316.
Corn-root worm, 316, 317.
Corn-root louse, 317.
Corpusculum, 109.
Coxa, of grasshopper, 261.
Crane-flies, 298.
Craponius inacqualis, 320.
Crickets, 180, 286; earlike or- gan of, 44; mode of produc-
336
INDEX AND GLOSSARY
ing sound in, 45 ; night
cricket in Japan, 46. Crops, rotation of, 302. Crown borers, 328. Cuckoo-flies, 290. Cucumber, insect enemies of,
317. Cucumber worm, 317.
Culex pungens, 154.
CulicioX 298, 323.
Ourculio, 290, 320.
Cureulionidse, 290.
Currant, insect enemies of, 318.
Currant saw-fly, 318.
Cut- worms, 319.
Cyanide bottle, use of, 253.
Cyaniris pseudargiolus, 40.
Cyclorrhapha, 299.
Dactylopius adonidum, 323.
Damsel-fly, 173.
Darkling beetles, 288.
Darwin on cross-fertilization, 95.
Day-flies, 286.
Dealers in entomological sup- plies, 237.
Dermestidse, 289.
Diabrotica loiigicornis, 316. 12-punctata, 318. vittata, 318.
Diaspis snowii, 188.
Digestive tract of honey-bee, 270; of grasshopper, 269-272.
Diptera, 196-198, 284, 298, 299.
Dissecting-needles, how to make, 252.
Dissosteira longipennis, 213, 215.
Distribution, modes of insect, 209.
Dobson-fly, 286.
Dorsal direction, 255. Doryphora dccem-lineata, 142,
143, 326. Dragon-flies, 172, 173, 174, 286;
how to rear, 240; number of
facets in compound eye of,
41.
Drone bee, 77.
Du Bartas, quotation from, 73. Dytiscidse, 288.
Earwig, 285.
Eggs, protection of, 47.
Egg-guide, 268.
Egg-pods, of yellow grasshop- per, 10; number of eggs in, 12; of cockroach, 153.
Elateridse, 289, 331.
Elfin butterfly, distribution of, 205.
Elm, insect enemies of, 320.
Elm-leaf beetle, 320.
Emphytus maculata, 329.
Erythroneura vitis, 321.
Engravers, 290.
Epicranium of grasshopper, 256.
Ephemeridae, 167.
Epimeron, of mesothorax, 262 ; of metathorax, 263.
Episternum, of mesothorax, 261; of metathorax, 263.
Erax cinerascens, 197.
Eristalis latifrons, 61.
Eudamus proteus, distribution of, 203.
Eudamus lathyllus, 195.
Eudioptis nitidalis, 317. hyalinata, 318.
Eumenidse, 291.
Eurymetopus taurus, 175.
Ephemeridee, 286.
INDEX AND GLOSSARY
337
Eyes of insects, simple and com- pound, 40.
Eyes of grasshopper, simple and compound, 255.
Fall army worm, 330.
Fall web worm, 311, 323.
Farm practices to prevent un- due increase of insects, 301.
Fauna, definition of, 207.
Feigning death, 219.
Femur, 261.
Fidia viticida, 320.
Field collecting, 226.
Filament, 96.
Fish moth, 166, 284.
Fleas, 197.
Flowers, self-sterile, 96-101.
Fluted scale, 212.
Food of black swallowtail but- terfly, 22, 23 ; of larva, 15, 16.
Forficulidse, 285.
Formalin, use in preservation, 223.
Formica sp., 309. Formic idee, 291. Four-striped plant-bug, 320. Fruit-grower, insect friends and
foes of, 120-134. Fruit worm, 328. Fulgoridse, 293.
Galea of grasshopper, 259. Galeruca xanthomelaena, 320. Gense of grasshopper, 256.
Geographic distribution, 202- 212.
Gelechia cerealella,, 135, 317. Geometridae, 297. Giant water -bug, 185, 293. Girard, quotation from, 55.
Gomphinae, 240.
Gooseberry, insect enemies of,
320.
Grain beetle, 317. Grain, weevil, 317. Grape, insect enemies of, 320. Grapevine flea beetle, 321. Grapevine fidea, 320. Grape saw-fly, 320. Grape slug, 320. Grapevine sphinx, 321. Grapta interrogationis, 195. Graptodera foliacea, 310.
chalybea, 321.
Grasshoppers, 182, 285, 317. Grasshoppers, injurious, 137-
141. Grasshoppers, the yellow, 3 ; life
history of, 3-12; anatomy of
255-276. Grasshopper, long- winged, 213-
215.
Green lettuce worm, 314. Green milkweed, 108. Green-fly, 294, 309, 321. Green striped maple worm, 321. Ground beetles, 288. Gryllidse, ISO, 286. Gryllotalpa borealis, 181. Gula of grasshopper, 259. Gypsy moth, 202, 204.
Habitat, 202. Haernatobia serrata, 322. Harlequin cabbage-bug, 314. Hawk moths, 296. Hawaii, appearance of milk- weed butterfly in, 207. Hearing, sense of, 43. flrJiothis armiger, 329. Hemerobidse, 286.
338
INDEX AND GLOSSARY
. Hemiptera, 183-189, 284, 292- 294.
Herbert on fertilization of plants, 95.
Hesperidse, 294.
Hessian fly, 330.
Heteroptera, 184, 185, 292.
Hexapoda, definition of, 283.
Hildebrand, on fertilization of alfalfa blossoms, 106, 107.
Home-making, of insects, 91, (J2.
Homoptera, 185-189, 293.
Honey-bee, 61; friend of the horticulturist, 131 ; visiting pear blossom, 98 ; life history of, 73-81.
Honey-dew, 83.
Hopperdozer, plan of, 140.
Horn-flies, 290; of cattle, 322.
Hornets, 85, 291.
Horns, protective, of caterpil- lar, 17.
Horse-flies, 928.
House ants, 153.
House-fly, 147, 147, 299; life history of, 196; laboratory exercises on, 244, 245.
House plants, insect enemies of, 322.
Hover-flies, 299.
Huber's experiments with ants, 82.
Humming-bird moth. 193, 296.
Uydropliilus, haunt of, 192.
Hydrobatidse, 292.
Hydrophilidse, 289.
Hydrophilus triangutaris, 189.
Hymenoptera, 198; plant-eat- ing, 198, 199; parasitic, 132, 199-201; stinging, 201, 284, 290, 291.
Hyphantria cunea, 311, 323. Hypopharynx, 260.
Ichneumon-fly, 290.
Ichneumoiiida}, 290.
Incisalia augustus, 205.
Incomplete metamorphosis, 1.
Injurious insects and modes of treatment, 309-331.
Insects, injurious, 309-331 ; ar- rangement of, 235 ; enemies of man, 154-158; friends of man, 158-161.
Insecticides, 303.
Instinct, 89-93; limitations of, 92.
Instinct and reason, 93. Interrogation butterfly, 195;
the larva of, 49 ; pupa of, 50,
51.
Jassida?, 293.
Jumping plant-lice, 294.
June-bug, 288, 323.
Kalliina paralecta, 56.
Katydid, 181; mode of produc- ing sound, 45.
Kermes nivalis, 187.
pubescens, 188.
Kerosene emulsion, 305.
Knight, on fertilization of plants, 95.
Labium of grasshopper, 259. Labrum of grasshopper. 258. Laboratory, aids in, 251. Lace-bugs, 292. Lace-winged flies, 48, 286. Lachnostcrna fusca, 323. Laeinia of grasshopper, 259. Ladybird, 133, 191, 289.
INDEX AND GLOSSARY
339
Lamellicornia, 287. Lampyridce, 289. Lantern-flies, 293. Larva, 2 ; protection of, 50. Leaf butterfly, 56. Leaf-hoppers, 293, 321. Leaf beetles. 288. Leaf-bugs, 292. Leaf-roller, 290, 328. Leaf-miners, 290. Leaf-crumpler, 322. Lecanium sp., 320. Lecaiiium aurantiacum, 187. Lepicloptera, 192, 284, 294-297
mode of spreading, 233. Leucania, 141. Libellulidse, 172-174. 280. LilieUula pulcliclla, 172, 174. Lice, true, 189. Lightning-bugs, 289. Linnaeus, 122. London purple, 304. Long-horned beetles, 288. Lubbock, on insect vision, 43. Lucanidae, 288. Lucky-bugs. 289. Locustidae, 280. Ln/ilif/i/inii fi~iif/i/><'>'iJ(i, 330-. Luna moth, 194. Lycaenidap, 294. Lygaeidae, 292.
Madagascar, 211. Maggot on cabbage. 314. Mailing insects, 230. Mullophaga, 175. Mallophagidae, 175, 287.
Map of a collecting vicinity. 228.
Map, an aid in note-taking, 229. March-flies, 298.
Materials for field collecting. 223.
Mandibles of grasshopper, 25S.
Mantis religiosa, 138.
Mantidae, 178, 285.
Maple, insect enemies of, 323.
Maple scale, 323.
Maple worm, 323.
Maxillae of grasshopper, 258.
May-flies, 107, 108.
May beetle, 323.
Mealy-bugs, 323.
Measuring-worms, 397.
Melanoplus differentialis, 3, 4;
anatomy of, 255-270. Mclitlia ceto, 328. Meloido?, 288, 313. A Felon worm, 318. Mentum of grasshopper, 259. Mrrula migratoria, 164. Metallic wood-borers. 289. Metamorphosis, 1, 238, 242. Memhracidu1. 293. Mesothoracie wing, 205. Mesothorax. 201. Metasternum, 203. Metathoracic leg, 204. Metatboracic wing, 265. Metasternum, 203.
Microscope stand, how to make 251.
.Milkweed butterfly. 207. Sec
-\nnfiin jili'.ri/ipus. Milkweed, fertilization of, 108-
112; entrapping insects, IK). Mimicry, 57. Mimicking moths. 59. Mimicking insects. 01. Mimicked insects. 01. Mole cricket. 1ST. Mosquitoes. 154-158. 298. 324.
840
INDEX AND GLOSSARY
Moths, classification of, 193. Molting, 2; of caterpillar, 10;
of a grasshopper, 4-7. Mouth-parts of grasshopper,
258.
Mud-daubers, 63, 291. Mud shed built by ants, 83. Murgantia histrionica, 314. Musca vomitoria, section
through eye of, 42. Musca domestica, 147. Muscidse, 299.
Natural selection, 61. Nematus ventricosus, 318. Nepidse, 293. Net, how to make, 223. Nervous system, of grasshopper,
272, 273.
Neuroptera, 167, 284, 286, 287. Noctuidae, 297. Note-book, use of, 227. Notonectidae, 293. Notodontidse, 297. Nymph, 2. Nurse-bees, 75. Nycteribia, 42. Nymphalidae, 294.
Observation, some points for,
240.
Oberca bimaculata, 313. Odors, production of, 39 ; of
butterfly, 40; uses of, 40. Oedipodinae, 182. Occanthus niveus, 313. Orders, list of, 165. Orgya leucostigma, 312. Orthezia graminis, 48. Orthorrhapha, 298. Orthoptera, 176-182, 284-286.
Ovipositor, 268 ; of grasshop- pers, 9.
Oviposition, manner of, in yel- low grasshopper, 9.
Ovule, 96.
Owlet moths, 297.
Paleacrita vernata, 311.
Palpi, uses of, 36.
Palpiger, of grasshopper, 259.
Palpus of grasshopper, 259.
Parapteron, 262.
Parasitism, 216-218.
Parasitica, 290.
Parasitic insects, 290.
Paris green used as spray, 130, 303.
Panorpida?, 286, 287.
Papilionidse, 294.
Papilio polyxenes, 13-23.
Parnassian butterfly, 207.
Pastinaca sativa, 13.
Pea, insect enemies of, 324.
Pea weevil, 324.
Peach, insect enemies of, 324.
Peach-tree borer, 325.
Pear, insect enemies of, 325.
Pear, fertilization of blossom, 97-101.
Pear-leaf blister, 325.
Pear-tree borer, 325.
Peckham, Geo. W. and Eliza- beth, quotation from, 71, 72.
Pelopaeus cementarius, 64.
Pentatomidse, 293.
Pepsis formosa, 68.
Perla epliyre, 169.
Perlidse, 168, 286, 287.
Petal, 96.
Petroleum as insecticide, 305.
Peucedanum foeniculaceum, 13.
INDEX AND GLOSSARY
841
Phasmidse, 180, 285. Phasmomantis Carolina, 179. PhlryctJiontins celcits, 193, 329. Phorbia brassicae, 315. Phoxoptcris comptana, 328. I'Jiifi-ifi iiulir/inella, 322. Pinning insects, mode of, 232. Phryganeidae, 176, 286, 287. Phytoptus pyri, 325. Pickle worm, 317. Pieris oleracea, 40. Pieris rapae, 144, 314. Pieridse, 294. Pigeon horn-tail, 198. Pin-hole borer, 312. Pitcher pupa, of humming-bird
moth, 195.
Plant-lice, 185, 186, 309, 321. Plant-lice cared for by aphids,
83.
Plants and insects, 94-118. Plum, insect enemies of, 326. Plum curculio, 312, 325, 326. Plum-gouger, 326. Plum scale, 326. Plitsia brassicae, 314. Podical plates of grasshopper,
of male, 267; of female, 268. Podisus spinosus, 53. Poecilocapftus lineatus, 320. Polistes, 85. Pompilidae, 291. Potato, insect enemies of, 326. Potato beetle, Colorado, 142. Praying mantis, 138, 178, 170,
285.
Predaceous insects, 133. Predaceous diving beetles, 288. Preservation of insects, 222.
230. Preserving materials, 225.
Preventives, 302.
Proboscis of butterfly, 23.
Prominents, 297.
Pronuba moth, 92 ; pollenizing
yucca lily, 112-118; head of.
114; ovipositor of, 114. Prothorax of grasshopper, 260. Prothoracic leg of grasshopper,
261.
Psilopa, 204. Psocidse, 286, 287. Psylla pyricola, 325. Psyllidse, 294. Ptilium, 42.
Pulvinaria innumerabilis, 323. Pulcinaria pruni, 121. Pupa, protection of, 50. Pupation of caterpillar, 18, 19.
Queen bee, 74-77.
Queen, of white ants, 170.
Quince, insect enemies of, 327.
Raspberry, insect enemies of, 327.
Records, manner of keeping, 228.
Red spider, 322, 327.
Red mite, 139.
Redtenbacher, on wing-venation. 295.
Reduviidse, 292.
Reference books, 332.
Relaxing insects, 236.
Reproductive system of gra-s hopper, 276.
Respiratory system of grass- hopper, 273-275.
Rhodites radicum, 313, 327.
Rhynchophora, 290.
Robber-fly, 197, 299.
342
INDEX AND GLO8BAKY
Robin, classification of, 164. Rootgall-fly, 313, 327. Root borer, 329. Root louse, 329; on apple, 311. Rose slug, 327. Rose, insect enemies of, 327. Rotation of crops, as insect pre- ventives, 302. Rove beetle, 289. Royal jelly, 75. Runners, 291.
Saturniidse, 297.
Samia cecropia, life history of, illustrated, 24-33.
San Jose scale, 188, 212, 32G.
Sannina exitiosa, 325.
Kaperda Candida, 309.
Sarcophaga cimbicis, 190.
Sarcophaga, transformations of, 146.
Saw-flies, 290, 329.
Scale insects, 185-187, 294, 322; remedies for, 306.
Searabseidae, 288.
Scent of butterflies, 40.
ticliisoneura lanigcra, 311.
Rcliizocerus cbenus, 329.
Scoliidae, 291.
Scolytus rugulosus, 312, 324.
Scolytidse, 290.
Scorpion-flies, 286, 287.
Scudder, S. H., 57.
Segments, normal number of, in caterpillar, 14.
Xclandria vitis, 3201.
Nclandria rosae, 327.
Selection, artificial, 219; nat- ural, 220.
Sepal, 96.
Sesia pyri, 325.
Kesia tipuliformis, 318. Shakespeare, quotation from, 73. Sialidse, 286. Sight, sense of, 40. Silphidse, 290. Silvanus surinamensis, 317. Siricidse, 290. Skeleton, exo-, endo-, 250. Skipper, swallowtailed, distribu- tion of, 203.
Skippers, 294 ; classification of, 193.
Slaves, of ants, 82.
Snout beetle, 191.
Smell, sense of, 37-39.
Snowy tree cricket, 313.
Social development, 63.
Social organization, 219.
Social wasps, 88, .291.
Solitary wasps, 291.
Sound, production of, 45.
Special senses, 34-46.
Species, number of, 162; varia- tion in, 163.
Sphegidse, 291.
Nphcnophorus, 316.
RphenopJioms ochreus, 191.
Rplicx speciosus, 92.
Sphingida?, 296.
Spiracles, 268.
Spittle insects, 294.
Spotted cucumber beetle, 318.
Spray nozzles, 308.
Spray pump, 304, 305.
Spraying machinery, 308.
Spraying for codling moth, 130.
Sprays, 303.
Spreading-board, 233.
Sprengel on fertilization, 94, 95.
Springtail, 166, 167, 285.
Squash, insect enemies of, 328.
INDEX AND GLOSSARY
JJUJ
Squash-bug, 143, 144, 292, 328.
Stag beetles, 288.
Stalk weevil, 326.
Slaphylinidse, 289.
Stigma, 96.
Sting of bee, means of defense, 52-54.
Stinging, instinctive, 90.
" Stink-bugs," 39, 293.
Hlumoxys, 158.
Stomoxys calcitrans, 147.
Stone-flies, 168, 177, 286, 287.
Strawberry, insect enemies of, 328.
Striped cucumber beetle, 318.
Structure and function of in- sects, 250-282.
Struggle of life, 212-214.
Style, of pear flower, 96.
" Sugaring," 230.
Supplies, dealers in, 237.
Swallowtail butterflies, 294; life history of, 13-23; how to rear, 242-244.
Swarming of bees, 79, 80.
Sympathetic coloration, 56.
Sweet potato, insect enemies of,
329. Syrphidee, 299.
Tabanidse, 298.
Tabanus, 158.
Taste, sense of, 36; in bees, 37;
in ants, 37 ; in wasps, 37. TenebrionidcT, 288. Tennyson, quotation from, 18. Tent caterpillar. 123, 312. Tenthredimdse, 290. Termites, 330. Termitidse, 169, 286, 287. Tetranyclius telarius, 327.
Thalessa lunator, 200.
Thrips, 183.
Thysanoptera, 182, 183, 284.
Thysanura, 166, 284.
7'/i i/rldopteryx cphemeracfonii in,
313.
Tibia, 261. Tiger beetles, 288. Tiger moths, 297. Tinea pellionella, 150, 315. Tineidae, 296. Tingitidse, 292. Tipulidse, 298.
Tomato, insect enemies of, 329. Tomato worm, 329. Touch, sense of, 36. Triclwbaris trinotata, 326. Trap-door spider, 89, 90. Tree cricket, eggs of, 49. Tree-hoppers, 293. Tremcx columba, 198. Trochanter, 261. Trombidium locustarum, 139. Tropical zone, 208. Tryxalinae, 182. Tussock moth, 312. Tyloderma fragariae, 328.
Umbelliferae, 13. Underground stingers, 291. Use of tools by an insect, 66-71.
Ventral direction, 254.
Vertex of grasshopper, 257.
Vespa, 85.
Vespa occidcntalis, 61.
Vespida\ 291.
Viceroy butterfly, 60, 162.
Volucella evecta, 61.
Waite on fertilization, 97, 101. Walking-sticks, 56, 180, 285.
344
INDEX AND GLOSSARY
Warning colors, 214, 216.
Wasps, 85-88 ; friends of horti- culturists, 132; solitary, 291; social, 291; thread-waisted, 291.
Water scavenger beetle, 189, 289.
Water-striders, 292.
Water-boatmen, 293.
Water scorpions, 293.
Wheat, insect enemies of, 330.
Whirligig beetles, 289.
" Wigglers," 154.
Weevils, 290.
Williston, S. W., quotation
from, 66. Worker bee, 77-79.
White ants, 169, 172, 286, 287, 330.
Wire worms, 331. Wood-boring beetle, 190.
Yellow-jackets, 85, 8'6. Yucca lily, fertilization of, 112- 118.
Zonal map of United States, 210.
Zones of life, 208.
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