332 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



EEPKODUCTIOX OF THE ARMY-WORM. 



An important announcement has lately been made by Pro- 

 fessor Riley, the eminent entomologist of St. Louis, in regard 

 to the eggs of the army-worm, Leucania iiniinincta^ in a paper 

 lately read before the Academy of Science of that city. Dr. 

 Riley states that at first view it seems singular that the eggs 

 of an insect that appears in such countless myriads, from 

 Maine to Georgia and from Virginia to Kansas, should have 

 remained undiscovered either by farmers or entomologists. 

 Stimulated by this rather discreditable fact, he made spe- 

 cial efforts to solve the problem, which have been recently 

 crowned with success by his having witnessed the mode of 

 oviposition on the blue grass. The eggs, as he had supposed, 

 were secreted, being either glued in rows of from five to 

 twenty in the groove which is formed by the folding of the 

 terminable grass blade, or in between the sheath and the 

 stalk. Sometimes they were pushed into crevices in the 

 ground, especially at the base of the grass stalk. The eggs 

 are white, slightly iridescent, spherical, and only two hun- 

 dredths of an inch in diameter. They are fastened to each 

 other and to the leaf, and covered along the exposed portion 

 by a white, glistening, viscid substance. 



By the seventh day after deposition the brown head of the 

 embryo shows distinctly through the shell. The larva hatch- 

 es the eighth to the tenth day, being less than two millime- 

 ters in length, of a dull translucent white color, with a large 

 brown-black head. On account of its extremely small size, 

 and the color resembling the pale bases of the grass stalks 

 near the ground, it is almost impossible to find them even 

 where there are dozens to the square foot. Proc. Acad, Nat. 

 JSc, St. Louis, May 8, 1876, 1111. 



STRUCTURE AND DEVELOPMENT OF MITES. 



These animals, represented by the cheese and itch mite, 

 are exceedingly numerous in species, and much attention has 

 been lately paid to them, judging by the memoirs published 

 in 1876 by French and German authors. Of the first impor- 

 tance is an elaborate work by A. L. Donnadieu, entitled 

 " Recherches pour servir a Phistoire des Tetranyques," pub- 

 lished in the Annates de la Societe Linneenne de Lyon., with 



