SCIENCE. Q I 



No. VIIL Insecta. 



By ALPHEUS HYATT and J. M. ARMS. 223 illustrations in the text and 13 

 plates. Cloth. 324 pages. Price, #1.25. 



'"THIS Guide is a series of replies to questions which have arisen in 

 1 the minds of its authors while teaching. No attempt has been 

 made to prepare a treatise for scholars but to gire a guide that will 

 enable instructors to give lessons with specimens, and dispense with 

 the use of books on the part of the pupil. The book is an original 

 work in many repects, but also describes in as compact form as possible 

 the elementary principles cf insect anatomy, physiology, and classifi- 

 cation. The " synopsis" of chapters preceding the book will be found 

 valuable to the teacher. The plates and illustrations, which have been 

 prepared with unusual care, illustrate the prominent structural charac- 

 ters of each order of Insects. 



No. XII. Common Minerals and Rocks. 



By W. O. CROSBY, Professor of Mineralogy in the Mass. Inst. of Technology 

 Illustrated with 40 figures. 200 pages. Price, paper, 40 cents. Cloth, 60 cents. 



THIS includes a brief and simple account of the principal geological 

 agencies, descriptions of all the more common and important 

 varieties of minerals and rocks, and an explanation of the leading 

 kinds of structure occurring in rocks, such as stratification, etc. 



It is not merely a guide to teachers, but also a simple and logical 

 presentation of the leading facts and principles of structural geology. 

 It is well adapted for class use, and is already used in many schools. 

 Specimens to Illustrate, from 50 cents to $10.00. 



No. XIII. First Lessons in Minerals. 



By ELLEN H. RICHARDS, Instructor in Mineralogy, Mass. Inst. of Technol- 

 ogy. Paper. 50 pages. Price, 10 cents. A valuable introduction to Guide No. 

 XII. 



'""pHESE lessons were first worked out with three successive classes of 

 1 children, from six to eight years old, just out of the Kindergarten, 

 and then given to classes in two public schools in the city of Boston. 



