ON STRUCTURE

Although in the foregoing chapter a little has been said on this subject, there is a great deal more that a student should learn about the general form of these creatures.

They begin life as white or nearly colourless grubs, which, after various changes of skin, assume what is called the nymph or pupa stage, during which a change occurs, believed to be peculiar to theHymenoptera; the fifth segment of the larval body is transferred to the mass which is called the thorax, so that a portion of what looks like thorax is really the first segment of the abdomen. Continental writers call this portion sometimes the first abdominal segment and sometimes the median segment, but Newman gave it a definite name, the "propodeum", and the most convenient method seems to be to call it so, and treat it as a part of the thorax, calling the first or basal segment of the abdomenthat which immediately follows the regional constriction, which occurs between the propodeum and the abdomen.

Fig 28. Parts of an aculeate

Fig. 28.aHead.a1Antennæ.a2Ocelli.a3Compound eyes.b1Prothorax.b2Scutum of Mesothorax.b3Scutellum of Mesothorax.b4Post-Scutellum of Metathorax.b5Propodeum.c1c2, etc., Segments of Abdomen.Legs.d1Coxa.d2Trochanter.d3Femur.d4Tibia.d5Tarsi.d6Calcaria or Spurs.d7Unguiculi or claws.d8Pulvillus.eFront wing. 1 Costal nervure. 2 Post Costal nervure. 3 Median nervure. 4 Posterior nervure. 5 Basal nervure. 6 Cubital nervure. 10 1st Recurrent nervure. 11 2nd Recurrent nervure.f.Hind wing. 7 Anterior nervure. 8 Median nervure. 9 Posterior nervure.Cells.AMarginal.BUpper basal.CLower basal.D1st Submarginal.E2nd Submarginal.F3rd Submarginal.G1st Discoidal.H2nd Discoidal.I3rd Discoidal.J1st Apical.K2nd Apical.

Fig. 28.

aHead.a1Antennæ.a2Ocelli.a3Compound eyes.

b1Prothorax.b2Scutum of Mesothorax.b3Scutellum of Mesothorax.b4Post-Scutellum of Metathorax.b5Propodeum.

c1c2, etc., Segments of Abdomen.

Legs.d1Coxa.d2Trochanter.d3Femur.d4Tibia.d5Tarsi.d6Calcaria or Spurs.d7Unguiculi or claws.d8Pulvillus.

eFront wing. 1 Costal nervure. 2 Post Costal nervure. 3 Median nervure. 4 Posterior nervure. 5 Basal nervure. 6 Cubital nervure. 10 1st Recurrent nervure. 11 2nd Recurrent nervure.

f.Hind wing. 7 Anterior nervure. 8 Median nervure. 9 Posterior nervure.

Cells.AMarginal.BUpper basal.CLower basal.D1st Submarginal.E2nd Submarginal.F3rd Submarginal.G1st Discoidal.H2nd Discoidal.I3rd Discoidal.J1st Apical.K2nd Apical.

The perfect insect when it emerges has therefore a head, a thorax of four segments, and an abdomen of seven visible dorsal segments in the male, and of six in the female. The ♂ has six ventral segments exposed, and often the apex of the eighth, which is frequently elongate, the seventh being almost always short and hidden; the eighth dorsal segment can be discovered hidden under the seventh, but it is very rarely exposed. The head (a) bears numerous appendages; a pair of antennæ (a1), usually of thirteen joints in the male and of twelve in the female; two compound eyes (a3), composed of many facets; three simple eyes (or ocelli) (a2), which are situated on its vertex; twomandibles; twomaxillæ, bearingpalpion each side, of a varying number of joints; and alabium, or tongue, which also bears at its base two four-jointed palpi (cf. fig. 20).

The thorax, as we are considering it, consists of four segments—theprothorax(b1), which bears the two front legs; themesothorax(b2), which bears the intermediate pair of legs and the anterior pair of wings; and themetathorax(b3), which bears the posterior pair of wings and the hind legs. Thepropodeum has no appendages. The mesothorax above has two parts, a larger portion in front called by some thescutum(b2), and a smaller portion behind called thescutellum(b3). These are separated from each other by a transverse impression, and the scutellum is often raised into a sort of little shield; behind this is another little elevation called thepost-scutellum(b4); this is really the dorsal apex of the metathorax, and behind this lies thepropodeum(b5). Each leg is composed of various parts, and articulates into a cavity of the thorax called theacetabulum. The first two joints of the leg, thecoxa(d1) and thetrochanter(d2), are very short; then follows thefemuror thigh (d3); then thetibiaor shin (d4); and finally thetarsi(d5), which compose the foot. At the apex of thetibiaare usually two spines called thecalcaria(d6). Thetarsiare five-jointed, the joints following each other in a linear arrangement, and in theAnthophilathe basal joint is more or less dilated; the apical joint bears two claws (unguiculi,d7) which are sometimes toothed, and between them, in some genera, there is what is called apulvillus(d8) or cushion; this is very large and dilated in some of the fossors.

The wing neuration is always rather troublesome, as various authors use different names for the veins and cells. To begin with the anterior wing (e), there are four nerves which start from the base and run horizontally; the first of these, which forms the anterior margin of the wing, is called thecostal nervure(1); immediately below this, and running almost parallel to it with scarcely any space between them, is thepost-costal nervure(2); these end in thestigma(s), a dark in-crassation towards the apex of the wing; from the stigma a nerve, curving first downwards and then up to the anterior margin of the wing, encloses themarginal cell(A). Below thepost-costalnervure, and situated about the centre of the wing, is the third longitudinal nervure called themedian nervure(3); behind this again runs theposterior nervure(4), and behind that the actual margin of the wing which is not provided with a protecting nervure, but is only folded back so as to receive the hooks of the posterior wing. Across the wing at, roughly, about a third of its length from the body runs thebasal nervure(5); this extends in a somewhat zigzag line from thepost-costalto theposterior nervurecrossing themedian, andthereby enclosing two cells, theupper basal cell(B) and thelower basal cell(C). From the centre of the apical nerve of each of these cells extends a longitudinal nervure; the upper of these runs out nearly to the apical margin of the wing and is called thecubital nervure(6); this is united to the nervure of themarginal cellby one, two, or three cross nervures, enclosing thereby one, two, or three cells called the first (D), second (E), and third (F)submarginal cells. The nervure from the lower basal cell is a short one, as it is met by a cross nervure called the firstrecurrent nervure(10), which runs from thecubitalto theposterior, thereby enclosing two cells, the first (G) and second (H)discoidal. Thesecond recurrent(11) leaves thecubitalnearer the apex of the wing than the first, meeting a nervure which, springing from the outer posterior angle of the second discoidal, closes the third discoidal (I), and, curving slightly upwards, nearly reaches the apical margin of the wing. Beyond the second recurrent, and behind this last nervure which we have been talking about, are two spaces not actually enclosed, but called thefirst(J)and second(K)apical cells.

The posterior wings have very few cells.Like the anterior pair they have three longitudinal nervures; theanterior(7), which runs close and parallel to the anterior nerveless margin, and often touches it at about half the length of the wing; themedian(8) andposterior(9) run in diverging lines from the base towards the exterior margin of the wing, the anterior and median nervures being almost always joined by a cross nervure, and the median usually united to the posterior by a cross or curved nervure. The actual base of the anterior wing is covered by a little convex somewhat shell-like cap, called thetegula(T). The abdomen is composed of a series of segments in linear arrangement (c1c2, etc.). These call for no special remark, beyond what has been said in the chapter on males and females, but those who wish to investigate the very interesting questions connected with the terminal segments of these creatures should consult some more technical work.[3]The arrangements of the mouth parts and of the apical segments of the Hymenoptera afford perhaps the most important structuralcharacters of the order, but they involve an amount of dissection and study which can only be undertaken by those who are inclined to give themselves up to this subject as a speciality.

Abdomen,125Acetabulum,135Ammophila,22Andrena,9,12,15,48,77,79,122,139— fulva,121— rosæ,138— thoracica,121Antennæ,101,103,134Anthidium,50,121Anthophila,6Anthophora,48,61,82,93,109,111,121— pilipes,61— retusa,62Ants,28,31,88Aphides,88Apis,16Astatus,103Banded bodies,120Beetles,20Biting,3,32Black Species,120Bombus,16— terrestris,41,42Brain,125Bramble Stems,12Breeding,113Broods,13Burrows,9Calcaria,70,135Carder Bees,40Cardines,75Carpenter bee,55Caterpillar,19,20Cells,10,12,28,29,40,58— hexagonal,28— pitcher-shaped,58— waxen,29,40Ceratina,47,128Chimneys,25Chloroform,118Chrysis,27Cilissa,48Cleaning hairs,68Clover fertilization,39Cockroaches,128Cocoons,33,58Coleoptera,128,129Colletes,44Colonies,5,63Colour,100Colour schemes,22Combs,23,68,69Corbicula,67Coxæ,135Crabro,95,102— albilabris,119Cuckoos,3,14,30,54— flight of,85Cyanide,116Dasypoda,48Development,124Digestion,125Diggers,6,7Diptera,129Distribution,105Domestication,41Drone flies,3Dufourea,106Earwigs,128English names,55Epeolus,45Ether,117Eyes,134Females,95Femur,135Figwort,36Figure of insect,133Flies,3,129Flower lovers,6Flute,57Food,6,28Foot,135Formica,34,59— fusca,119— sanguinea,89Formicoxenus,96Fossors,6,7Galleries,28Grasshoppers,19,128Growth,126Guests of Ants,89Hairs,65,71Halictus,13,15,17,77,94,97,119,122Head,125Hemiptera,129,130Heterogyna,28,31Heteromorphæ,130Hive bee,2,16Homing instinct,21Homomorphæ,130Honey pots,29Hornets,35Humble bees,39— mutilated,41Hymenoptera,128,129Ichneumons,21Inquilines,3Jewel flies,21,27Keyhole wasps,101Killing bottles,126Knife-like hairs,68Labels,118Labial palpi,5Labium,127,134Larva,11,13Lasius niger,91— flavus,91Latin names,55Lawn bee,9Leaf-cutting bees,52Lepidoptera,129Ligula,75,134Limbs,125,127Locomotion,125Lodgers with ants,89Lomechusa,89Long-horned bee,104Lora,74Lysimachia,106Macropis,106Males,95Male wasp,2— hornet,2Mandibles,127,129Mason bee,55Maxillæ,75,127,134Mayflies,128Melecta armata,61— luctuosa,62Mentum,74Metœcus paradoxus,38Mimicking flies,94Miscophus,119Moss,29Mouse's nest,29Mouth,128Mutilla,112,119Myrmica,34Myrmosa,100Nests,24,26,31,35,45,49— in bramble stems,45— Humble bees,40— of leaves,53— of paper,37— in wren's nest,41Neuration,136— figure and explanation of,133Neuroptera,128,129Nodes,33Nomada,15,48Non-predaceous hymenoptera,3Nymph,11Odynerus,24Orthoptera,128,130Osmia,48,56,120— bicolor,59,121— inermis,58— leucomelana,57— parietina,58— rufa,56Ovaries,4Ovipositer,1Oxybelus,86Palm,82Palpi,134Panurgus,49Paper,37Paraglossæ,76Paralytics,18Plant lice,19Poison bags,1Pollen collecting,65Pompilus,87Ponera,33Porterage,34Post-scutellum,135Predaceous species,3Preservation,116Propodeum,132,135Prosopis,44,46— cornuta,47Pulvillus,135Queens,4Rarity,105Ray, John,63Sallows,82Sandy bank,83Saropoda,93,111Scale,33Scrophularia,36Scutellum,135Scutum,135Segments,96Setting,117Sexual structure,100Shin,135Snail shells,12,57Social species,3,4,28Solitary species,3,4,6Spade-like hairs,69Sphecodes,13,15,17,48,97,122Spiders,19Stinging,2,38Stings,2,32Stipes,74Straws,12Structure,132Stylops,77Submentum,74Swarming,29Tarsi,135Tegula,133,138Thigh,135Thorax,125,129Tibia,135Tomtit,42Tongues,15,39,44,49,66,72Trochanter,135Tubular entrance,25Unguiculi,135Vagaries of structure,104Velleius dilatatus,38Vespa sylvestris,36Walls,12Wasps, social,35— solitary,24Waspy coloration,120,121Wings,110— cells,112,133— folded,24,28— hooks,110— nervures,133Workers,4Wrens' nests,41Yellow-coloured species,120

Abdomen,125Acetabulum,135Ammophila,22Andrena,9,12,15,48,77,79,122,139— fulva,121— rosæ,138— thoracica,121Antennæ,101,103,134Anthidium,50,121Anthophila,6Anthophora,48,61,82,93,109,111,121— pilipes,61— retusa,62Ants,28,31,88Aphides,88Apis,16Astatus,103

Abdomen,125

Acetabulum,135

Ammophila,22

Andrena,9,12,15,48,77,79,122,139

— fulva,121

— rosæ,138

— thoracica,121

Antennæ,101,103,134

Anthidium,50,121

Anthophila,6

Anthophora,48,61,82,93,109,111,121

— pilipes,61

— retusa,62

Ants,28,31,88

Aphides,88

Apis,16

Astatus,103

Banded bodies,120Beetles,20Biting,3,32Black Species,120Bombus,16— terrestris,41,42Brain,125Bramble Stems,12Breeding,113Broods,13Burrows,9

Banded bodies,120

Beetles,20

Biting,3,32

Black Species,120

Bombus,16

— terrestris,41,42

Brain,125

Bramble Stems,12

Breeding,113

Broods,13

Burrows,9

Calcaria,70,135Carder Bees,40Cardines,75Carpenter bee,55Caterpillar,19,20Cells,10,12,28,29,40,58— hexagonal,28— pitcher-shaped,58— waxen,29,40Ceratina,47,128Chimneys,25Chloroform,118Chrysis,27Cilissa,48Cleaning hairs,68Clover fertilization,39Cockroaches,128Cocoons,33,58Coleoptera,128,129Colletes,44Colonies,5,63Colour,100Colour schemes,22Combs,23,68,69Corbicula,67Coxæ,135Crabro,95,102— albilabris,119Cuckoos,3,14,30,54— flight of,85Cyanide,116

Calcaria,70,135

Carder Bees,40

Cardines,75

Carpenter bee,55

Caterpillar,19,20

Cells,10,12,28,29,40,58

— hexagonal,28

— pitcher-shaped,58

— waxen,29,40

Ceratina,47,128

Chimneys,25

Chloroform,118

Chrysis,27

Cilissa,48

Cleaning hairs,68

Clover fertilization,39

Cockroaches,128

Cocoons,33,58

Coleoptera,128,129

Colletes,44

Colonies,5,63

Colour,100

Colour schemes,22

Combs,23,68,69

Corbicula,67

Coxæ,135

Crabro,95,102

— albilabris,119

Cuckoos,3,14,30,54

— flight of,85

Cyanide,116

Dasypoda,48Development,124Digestion,125Diggers,6,7Diptera,129Distribution,105Domestication,41Drone flies,3Dufourea,106

Dasypoda,48

Development,124

Digestion,125

Diggers,6,7

Diptera,129

Distribution,105

Domestication,41

Drone flies,3

Dufourea,106

Earwigs,128English names,55Epeolus,45Ether,117Eyes,134

Earwigs,128

English names,55

Epeolus,45

Ether,117

Eyes,134

Females,95Femur,135Figwort,36Figure of insect,133Flies,3,129Flower lovers,6Flute,57Food,6,28Foot,135Formica,34,59— fusca,119— sanguinea,89Formicoxenus,96Fossors,6,7

Females,95

Femur,135

Figwort,36

Figure of insect,133

Flies,3,129

Flower lovers,6

Flute,57

Food,6,28

Foot,135

Formica,34,59

— fusca,119

— sanguinea,89

Formicoxenus,96

Fossors,6,7

Galleries,28Grasshoppers,19,128Growth,126Guests of Ants,89

Galleries,28

Grasshoppers,19,128

Growth,126

Guests of Ants,89

Hairs,65,71Halictus,13,15,17,77,94,97,119,122Head,125Hemiptera,129,130Heterogyna,28,31Heteromorphæ,130Hive bee,2,16Homing instinct,21Homomorphæ,130Honey pots,29Hornets,35Humble bees,39— mutilated,41Hymenoptera,128,129

Hairs,65,71

Halictus,13,15,17,77,94,97,119,122

Head,125

Hemiptera,129,130

Heterogyna,28,31

Heteromorphæ,130

Hive bee,2,16

Homing instinct,21

Homomorphæ,130

Honey pots,29

Hornets,35

Humble bees,39

— mutilated,41

Hymenoptera,128,129

Ichneumons,21Inquilines,3

Ichneumons,21

Inquilines,3

Jewel flies,21,27

Jewel flies,21,27

Keyhole wasps,101Killing bottles,126Knife-like hairs,68

Keyhole wasps,101

Killing bottles,126

Knife-like hairs,68

Labels,118Labial palpi,5Labium,127,134Larva,11,13Lasius niger,91— flavus,91Latin names,55Lawn bee,9Leaf-cutting bees,52Lepidoptera,129Ligula,75,134Limbs,125,127Locomotion,125Lodgers with ants,89Lomechusa,89Long-horned bee,104Lora,74Lysimachia,106

Labels,118

Labial palpi,5

Labium,127,134

Larva,11,13

Lasius niger,91

— flavus,91

Latin names,55

Lawn bee,9

Leaf-cutting bees,52

Lepidoptera,129

Ligula,75,134

Limbs,125,127

Locomotion,125

Lodgers with ants,89

Lomechusa,89

Long-horned bee,104

Lora,74

Lysimachia,106

Macropis,106Males,95Male wasp,2— hornet,2Mandibles,127,129Mason bee,55Maxillæ,75,127,134Mayflies,128Melecta armata,61— luctuosa,62Mentum,74Metœcus paradoxus,38Mimicking flies,94Miscophus,119Moss,29Mouse's nest,29Mouth,128Mutilla,112,119Myrmica,34Myrmosa,100

Macropis,106

Males,95

Male wasp,2

— hornet,2

Mandibles,127,129

Mason bee,55

Maxillæ,75,127,134

Mayflies,128

Melecta armata,61

— luctuosa,62

Mentum,74

Metœcus paradoxus,38

Mimicking flies,94

Miscophus,119

Moss,29

Mouse's nest,29

Mouth,128

Mutilla,112,119

Myrmica,34

Myrmosa,100

Nests,24,26,31,35,45,49— in bramble stems,45— Humble bees,40— of leaves,53— of paper,37— in wren's nest,41Neuration,136— figure and explanation of,133Neuroptera,128,129Nodes,33Nomada,15,48Non-predaceous hymenoptera,3Nymph,11

Nests,24,26,31,35,45,49

— in bramble stems,45

— Humble bees,40

— of leaves,53

— of paper,37

— in wren's nest,41

Neuration,136

— figure and explanation of,133

Neuroptera,128,129

Nodes,33

Nomada,15,48

Non-predaceous hymenoptera,3

Nymph,11

Odynerus,24Orthoptera,128,130Osmia,48,56,120— bicolor,59,121— inermis,58— leucomelana,57— parietina,58— rufa,56Ovaries,4Ovipositer,1Oxybelus,86

Odynerus,24

Orthoptera,128,130

Osmia,48,56,120

— bicolor,59,121

— inermis,58

— leucomelana,57

— parietina,58

— rufa,56

Ovaries,4

Ovipositer,1

Oxybelus,86

Palm,82Palpi,134Panurgus,49Paper,37Paraglossæ,76Paralytics,18Plant lice,19Poison bags,1Pollen collecting,65Pompilus,87Ponera,33Porterage,34Post-scutellum,135Predaceous species,3Preservation,116Propodeum,132,135Prosopis,44,46— cornuta,47Pulvillus,135

Palm,82

Palpi,134

Panurgus,49

Paper,37

Paraglossæ,76

Paralytics,18

Plant lice,19

Poison bags,1

Pollen collecting,65

Pompilus,87

Ponera,33

Porterage,34

Post-scutellum,135

Predaceous species,3

Preservation,116

Propodeum,132,135

Prosopis,44,46

— cornuta,47

Pulvillus,135

Queens,4

Queens,4

Rarity,105Ray, John,63

Rarity,105

Ray, John,63

Sallows,82Sandy bank,83Saropoda,93,111Scale,33Scrophularia,36Scutellum,135Scutum,135Segments,96Setting,117Sexual structure,100Shin,135Snail shells,12,57Social species,3,4,28Solitary species,3,4,6Spade-like hairs,69Sphecodes,13,15,17,48,97,122Spiders,19Stinging,2,38Stings,2,32Stipes,74Straws,12Structure,132Stylops,77Submentum,74Swarming,29

Sallows,82

Sandy bank,83

Saropoda,93,111

Scale,33

Scrophularia,36

Scutellum,135

Scutum,135

Segments,96

Setting,117

Sexual structure,100

Shin,135

Snail shells,12,57

Social species,3,4,28

Solitary species,3,4,6

Spade-like hairs,69

Sphecodes,13,15,17,48,97,122

Spiders,19

Stinging,2,38

Stings,2,32

Stipes,74

Straws,12

Structure,132

Stylops,77

Submentum,74

Swarming,29

Tarsi,135Tegula,133,138Thigh,135Thorax,125,129Tibia,135Tomtit,42Tongues,15,39,44,49,66,72Trochanter,135Tubular entrance,25

Tarsi,135

Tegula,133,138

Thigh,135

Thorax,125,129

Tibia,135

Tomtit,42

Tongues,15,39,44,49,66,72

Trochanter,135

Tubular entrance,25

Unguiculi,135

Unguiculi,135

Vagaries of structure,104Velleius dilatatus,38Vespa sylvestris,36

Vagaries of structure,104

Velleius dilatatus,38

Vespa sylvestris,36

Walls,12Wasps, social,35— solitary,24Waspy coloration,120,121Wings,110— cells,112,133— folded,24,28— hooks,110— nervures,133Workers,4Wrens' nests,41

Walls,12

Wasps, social,35

— solitary,24

Waspy coloration,120,121

Wings,110

— cells,112,133

— folded,24,28

— hooks,110

— nervures,133

Workers,4

Wrens' nests,41

Yellow-coloured species,120

Yellow-coloured species,120


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