BIBLIOGRAPHY OF ECONOMIC ENTOMOLOGY. 
71 
1147. Penny, C. L. The diffusion of hydrocyanic-acid vapor in an 
enclosed space. <28th Ann. Rept. Delaware Agric. Exp. 
Station, 1901, pp. 218-235. 
1148. Pergande, Th. The southern grain louse ( Toxoptera grami- 
num Rond.). <Bull. No. 38, n. s., Div. Entom., U. S. 
Dept. Agric., November, 1902, pp. 7-19, 1 pi. 
1149. Pergande, Th. On some of the aphides affecting grains and 
grasses of the United States. <Bull. No. 44, Div. Ent., U. S. 
Dept. Agric., April, 1904, pp. 5-23, 4 figs. 
1150. Pergande, Th. A new enemy of the pear. <Bull. No. 44, 
Div. Ent., U. S. Dept. Agric., April, 1904, p. 88. 
1151. Perkins, G. H. The forest caterpillar. <Bull. No. 76, Ver¬ 
mont Agric. Exp. Sta., March, 1900, pp. 113-137, 13 figs., 
3 pis. 
Treats of Clisiocampa disstria Hiibn. 
1152. Peters, A. T. Mange in cattle and horses, and lice on hogs. 
<Bull. No. 74, Nebr. Agric. Exp. Sta., May, 1902, pp. 27, 
7 figs. 
1153. Pettit, R. H. Some insects of the year 1899. <Bull. No. 180, 
Mich. Agric. Exp. Sta., March, 1900, pp. 117-141, 15 figs. 
Notes on a number of species. 
1154. Pettit, R. H. A leaf-miner, Chironomus sp. in water-lilies. 
<First Rept. Mich. Acad. Sciences, 1900, pp. 110-111, 1 pi. 
1155. Pettit, R. H. Insect and animal life on the Upper Peninsula 
experiment station. Bull. No. 186, Mich. Agric. Exp. Station, 
December, 1900, pp. 28-42, 6 figs. 
1156. Pettit, R. H. Some insects of the year 1901. <Bull. No. 200, 
Mich. Agric. Exp. Station, May, 1902, pp. 179-212, 21 figs. 
1157. Pettit, R. H. Mosquitoes and other insects of the year 1902. 
<Special Bull. No. 17, Mich. Agric. Exp. Station, January, 
1903, pp. 26, figs. 26. 
1158. Pettit, R. H. Insects injurious to fruits in Michigan. <Spe- 
cial Bull. No. 24, Mich. Agric. Exp. Station, 1904, pp. 79, 
70 figs. 
1159. Phillips, J. L. Notes on Melanoplus femoratus Burm. <Bull. 
No. 40, Div. Entom., U. S. Dept. Agric., August, 1903, p. 87. 
1160. Phillips, J. L. Fourth report of the State entomologist and 
plant pathologist on the San Jose scale and the administration 
of the crop pest laws of Virginia. <Richmond, Va., 1904, 
pp. 46, pis. 9. 
1161. Phillips, J. L., and H. L. Price. The English pea louse. 
<Southern Planter, April, 1900. 
