182 
zooLooy. 
laying up pellets of pollen in some subterranean mouse- 
nest or in a stump, and the young hatching, gradually eat 
the pollen, and when it is exhausted and they are fully fed, 
they spin an oval cylindrical cocoon; the first brood are 
workers, the second males and females. The partly hex- 
agonal cells of the stingless bees of the tropics {Melipona) 
are built by the bees, while the hexagonal cells of the honey- 
bee are made by the bees from wax secreted by minute 
glands in the abdomen. Though the cells are hexagonal, 
they are not built with mathematical exactitude, the sides 
not always being of the same length and thickness. 
The cells made for the young or larval drones are larger 
than those of the workers, and the single queen-cell is large 
and irregularly slipper- shaped. Drone-eggs are supposed 
not to be fertilized. Certain worker-eggs have been known 
to transform into queen-bees. On the other hand, woiker- 
bees may lay drone-eggs. The maximum longevity of a 
worker is eight months, while some queens have been 
known to live five years. The latter will often, under fa- 
vorable circumstances, lay from 2000 to 3000 eggs a day. 
The first brood of workers live about six weeks in summer, 
and are succeeded by a second brood. 
Literature of Arthropod a. (For Crustacea see p. 85.) 
Podoslomata. — Van der Hoeveu's Recberches siir rHistoire Natu- 
relle des Limules, 1838; Milue-Edwards's Recherches sur TAna- 
tomie des Limules, 1872; Packard's Four Memoirs on the Anatomy 
and Embryology of Limulus, 1872-91; Kingsley's Notes on the Em- 
bryology of Limulus, 1885; works of Walcott, Dohrn, Lankester. 
Arachnida. — Hentz's Spiders of tbe 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., 1889-92; with the works 
of Walckenaer, Black wall, Thorell, Simon, Eeyserling, Marx, etc. 
Myriapoda. — Wood's The Myriapoda 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 Eotomology, 1836; Westwood's Modern 
Classification of Insects, 2 vols., 1839-40; Harris' Treatise on In- 
sects injurious to Vegetation, 1886; Packard's Guide to the Study of 
Insects, 1888; Entomology for Beginners, 1890; Graber's Die Insek- 
ten, 1877; Lubbock's Ants, Bees, "and Wasps, 1882. For economic 
entomology, the works of Harris, Fitch, Riley, Le Baron, Lintner. 
