EXPLANATION OF PLATE I.. All the figures enlarged unless otherwise stated, the hair-lines indicating the natural sizes. FIG. 1.-Egg-pod of Caloptenus differentialis with the mouth torn open, exposing the newly-hatched larva of Epicauta vittata (1 a) eating into an egg, and the passage which it made through the mucous covering-natural size. FIG. 2.-Dorsal view of the first larva, or triungulin, of E. vittata; 2 a, one side of the head of same from beneath, greatly enlarged so as to show the mouth parts; 2 b, terminal joint of maxillary palpus showing imbrications and flattened inner surface armed with stout points; 2c, leg, showing more plainly the tarsal spines; 2 e, labrum; 2 d, one of the abdominal joints from above, showing stout points, stigmata and arrangement of spinous hairs. FIG. 3.-Eggs of E. vittata, the natural size indicated at side. FIG. 4.-Dorsal view of the Carabidoid stage of the Second Larva of E. vittata; 4 a, its antenna; 46, its right maxilla; 4 c, its leg; 4 d, side view of same, showing its natural position within the locust-egg mass. FIG. 5.—Lateral view of the ultimate or full-grown stage of the Second Larva of E. vittata; 5 a, portion of the dorsal skin, showing short setaceous hairs. FIG. 6.-Third head, or that from the Scarabæidoid stage of the Second Larva of E. vittata, from beneath, showing the reduction of mouth-parts as compared with the first head (2 a); 6a, antenna of same; 6 b, maxilla of same; 6 c, mandibles of same. FIG. 7.-Fourth head, or that of the full-grown larva of E. vittata, from above; 7 a, leg of same; 7 b, the breast-plate or prosternal corneous piece. FIG. 8.-Lateral view of the pseudo-pupa or Coarctate Larva of E. vittata, with the partially shed skin adhering behind; 8 a, dorsal view of same; 8 bits head from the front; 8 c, same from side; 8 d, tuberculous leg; 8 e, raised spiracle; 8 f, anal part of same. FIG. 9.-Lateral view of the true pupa of Epicauta cinerea Forst.; 9a, ventral view of same. FIG. 10.-Epicauta vittata (lemniscata or trivittate var.). FIG. 11.—Epicauta cinerea Forst (= marginata Fabr.). FIG. 12.-Antenna of the triungulin of Epicauta pensylvanica; 12 a, maxilla of same; 12 b, labial palpus of same. FIG. 13- Hornia minutipennis, dorsal view, 13 a, lateral view of same; 136, simple claw of same; 13 c, Coarctate Larva; 13 d, leg of ultimate stage of Second Larva. VERY singular and amusing stories have been, and still are, accepted by many of the amicable relationship existing between the prairie dog, burrowing owl and rattlesnake. It is not within the province of the present article to repeat them, for they are familiar to every school boy. Many of their habits, however, are yet little understood, and I shall endeavor to give the results of several years observation on the plains and in the mountains. The prairie dog (Cynomys ludovicianus) is widely extended through nearly all the Rocky Mountain region of the United States, and seems to thrive equally well in the bleak regions of the Upper Yellowstone, or in the fervid tableau of Central Mexico. In the rich, fertile lands of Central Kansas, they sometimes become disagreeable nuisances to the farmers, making sad havoc among the fields of growing grain. In the dry, scorched deserts of Southern Colorado, I have seen the villages where one would almost suppose the simplest forms of animal life were incapable of being supported. In the cold, bleak Laramie plains, where but little vegetation save the sage brush can exist, and where for more than six months in the year they seldom dare expose themselves to the bitter winds, they thrive in countless numbers. They are, however, provident little fellows, and literally make hay while the sun shines! Late in the summer one will frequently meet burrows, around the entrance of which, for some distance, the grass has been neatly mown, and left to cure. Were he to visit any of them a day or two later, he would find the hay all cleanly removed. In a few instances I have surprised the inhabitants carrying the nicely preserved hay into their dwellings. As their |