THIRTEENTH WEEK. 



The work of this week is elective. For directions see under 

 twelfth week. 



ELECTIVE WORK. Field Work. 



NEEDED. Slides, covers, glycerine jelly, alcohol, oil of cloves, 

 and balsam. 



TWELFTH WEEK. In the field: Search for a plant affected with 

 large scale insects. Note the general appearance of the affected plant. 

 Note the abundance and distribution of the scale insects on the plant. 

 Look for evidences of parasitism and work of predaceous insects, collect 

 any specimens that may show such work and also twigs containing 

 normal scales. In the laboratory: Look for eggs and young and con- 

 tinue the search for parasites. Mount the eggs and young if found, in 

 glycerine jelly, as follows: With the point of a penknife pick out a piece 

 of jelly about one sixteenth of an inch in diameter and place on the center 

 of a slide. Upon this place the insect to be mounted and lay on the cover 

 glass and gently heat until the jelly becomes fluid. Examine under 

 the microscope and describe briefly. Determine the species by U. S. 

 Agr. Report for 1880. 



THIRTEENTH WEEK. In the field: Search for a plant affected 

 with small whitish scales and do as directed above for the large scales. 

 In the laboratory: Mount specimens of the insects from beneath the 

 scales in glycerine jelly, as directed above, and in Canada balsam, as fol- 

 low: Place the insects in alcohol five minutes and then in oil of cloves 

 about the same length of time. Now put a small drop of balsam on 

 the center of the slide and the insect upon it, and cover. Warm gently 

 as before. Determine the species by U. S. Agr. Report for 1880 and 

 Cornell University Report for 1882. 



FOURTEENTH WEEK. In the field: Turn over a piece of sod 

 with a spade and carefully pick the earth to pieces searching for root- 

 feeding larvae. Look for and note any evidences of injury, and collect 

 specimens. In the laboratory: Determine, as nearly as possible from 

 books and the collection, the grcup of the insects found and make a 

 brief descriptive note of each. Properly mount and label each specimen. 



FIFTEENTH WEEK. In the field: Look for a tree or fallen log 

 affected with borers; collect specimens of the insects and of their 

 work. In the laboratory: Determine, as nearly as possible, the insects 

 collected. Make a descriptive note of the insects and sketches showing 

 their work. Properly mount and label the material collected. 



SIXTEENTH WEEK. In the field: Look for a leaf-eating or fruit- 

 eating insect and collect specimens. In the laboratory: Determine, 

 mount and note as above. 



