XIV ILLUSTRATIONS. 



23. Armed Palisade-worm of Horse [Sclero&tomum armatum) 71 



24. Vermiceous Aneurism of Great Mesenteric Artery . . 72 



25. Sclerostovium tHracanthum . 73 



26. Small Red Sclerostome {S. rubrum) from Horse . 73 



27. Gape AYorm {Syngamus trachealis) 74 



28. Trichinella spiralis ... .77 



29. Eelworms {AnguUlulidai) . . 79 



30. Ear Cockles in Corn {Tylenchus scandens) SO 



31. Wheat attacked by Tylenchus sca-ndens 81 



32. The Stem Eelworm {Tylenchus dcrasCatrix. Kiihn) 82 



33. The Beet Eelworm {ffeterodera schachtii) 83 



34. Ascaridco .... 86 



35. Oxyures of Horse (Ourvula) ... 87 



36. Oxyures of Horse [Mastigodes) . . 88 



37. The Horse-Leech {Huemopis sanguisuga) . 95 



38. Structure of an Arthropod {Periplancta americana) 100 



39. Head and Lower Lip of Cockroach . . 101 



40. Structure of Insect Leg . . . 104 



41. Digestive Organs of the Cockroach . . 105 



42. Trachea and side-view of part of Abdomen . 106 



43. Iv'ervous System . . . 108 



44. Wood-lice {Animdillidinm mlgarix, Porcellio scaler, and antenna 



of Oniscus, &c.) 109 



45. MiWe-peiiea {Blanjulus jndi/ullus and lulus Londincnsis) . 112 



46. Millepedes (1, Blanjulus pulchellus ; 2, Polydesmus complaimtus) ; 



Centipede (3, Geophilus suiter runeus) . 113 



47. House Spider {Tegenaria civilis) . . . 115 



48. Orb-weaving Spider, &c. . . . . . 117 



49. Harvest Bug (Trombidium holosericeum) . , 119 



50. Harvest Bug (Leptus autumnalis) , . 120 



51. UeA Spider (Tetranychus ielarius) . . 121 



52. Red Hen Mite (Dermanyssus avium) and Egg , 122 



53. Head of a Tick ... . 123 



54. External parts of a Tick . . . , .124 



55. Female Tick laying Eggs . . 125 



56. Female Sheep-scab Mite . . . 129 



57. Red Mange . , . . lai 



58. Demodectic Scabies (section of skin) . , 132 



