368 ZOOLOGY. 



the rows of teeth examined. The thoracic and abdominal portions of 

 the nervous system, which lies loosely on the floor of the body, can be 

 readily found by raising the alimentary canal ; but the brain and infra- 

 ossophageal ganglia can best be detected by a longitudinal section of 

 the head. The ovaries always lie above the intestine, and the two 

 oviducts unite below the nervous cord to form the common duct which 

 opens on the ventral side of the third segment in front of the anus, 

 which is situated dorsally. Insects should be dissected in a shallow 

 pan lined with wax or cork, and the parts floated out ; fresh specimens 

 are desirable. The body may also be dissected, each segment with its 

 appendages being separated and glued in their true sequence to a card. 

 By simply dissecting an insect in this way, the student will acquire a 

 valuable knowledge of the external structure of insects. 



LITERATURE OF ARTHROPODA. 



Crustacea. Milne-Edwards's Histoire Nattirelle des Crustaces. S 

 vols., 1834-1840. Dana's Crustacea of the U. S. Exploring Expedi- 

 tion. 2 vols., 1852. Gerstaecker's Arthropoden (in Broun's Classen 

 und Ordnungen des Thierreichs). 2 vols., 1866-1891. Huxley's 

 The Crayfish, 1880. Packard's Monograph of North American Phyl- 

 lopod Crustacea, 1883. Also the writings of Say, Dohrn, Sars, 

 Claus, Brooks, Hagen, Faxon, Smith, Kingsley, etc. 



Podostomata. Van der Hoeven's Recherches sur 1'Histoire Natu- 

 relle des Limules, 1838. Milne-Edwards's Recherches sur 1'Auatomie 

 des Limules, 1872. Packard's Four Memoirs on the Anatomy and 

 Embrj'ology of Limulus, 1872-1891. Kingsley's Notes on the Em- 

 bryology of Limulus, 1885. Also the essays of Walcott, Dohrn, 

 Brooks, Lankester, Bruce, and Kishinouye. 



Araclmida. Hentz's Spiders of the United States. Boston, 1875. 

 Emerton's Structure and Habits of Spiders, 1883, and his various 

 essays, with those of G. W. and E. G. Peckham. McCook's American 

 Spiders and their Spinning Work. 3 vols., 1889-1892. With the 

 works of Walckenaer, Blackwall, Thorell, Simon, Moggridge, Bert- 

 kau, Keyserling, Marx, etc. 



Myriopoda. Wood's The Myriopoda of North America, 1865. With 

 essays by Newport, Harger, Latzel, Haase, Packard, etc. 



Insecta. Kirby and Spence's Introduction to Entomology. 4 vols., 

 1828. Burmeister's Manual of Entomology, 1836. Westwood's Mod- 

 ern Classification of Insects. 2 vols., 1839-1840." Harris's Treatise on 

 Insects injurious to Vegetation, 1886. Packard's Guide to the Study 

 of Insects, 1888. Packard's Entomology for Beginners. New York, 

 1890. Graber's Die Insekten, 1877. Kolbe's Einfuhrung in die 

 Kenntniss der Insekten, 1889-1892. Lubbock's Ants, Bees, and Wasps, 

 1882. For economic entomology, the works of Harris, Fitch, Riley, 

 Le Baron, Lintner, etc.; also for journals, Insect Life, Washington; 

 Psyche, Cambridge, Mass.; Canadian Entomologist, etc. 



