ARTHROPOD A 271 



securing of material the students should -make observations on 

 the following points : 



1. Habits. Where and under what circumstances found? 

 At what time of the year does this species occur in greatest 

 abundance ? Under what circumstances are they most active ? 



2. Methods of Locomotion. How many methods seem 

 available? Degree of efficiency of each? Under what circum- 

 stances is each used? What distance can be attained at one 

 effort? Continue the study later in more limited quarters, as 

 in the room and under a bell-glass. Compare the work of the 

 various legs. Are the wings used at all in jumping ? 



3. Protective Features. Coloring; to what extent do you 

 find this of protective value ? Reasons. Does the animal show 

 a distinct instinct for hiding ? Compare all available species in 

 these regards. 



4. Do they produce definite sounds? Under what circum- 

 stances ? Do you find any hint as to the method of their pro- 

 duction ? 



5. Do you detect any movements which suggest respiration? 

 Rate ? (Find spiracles in the thorax and abdomen.) 



6. Supply hungry animals with fresh leaves and study the 

 feeding process. Dip the leaves in various solutions and notice 

 whether it makes any difference to the grasshopper. 



If alcoholic material is used for the following morphological 

 studies it should not be allowed to become dry. If dipped in 

 a mixture of glycerine and 50 per cent, alcohol, specimens will 

 not dry so rapidly. 



The sexes differ, particularly in the abdominal region. Pro- 

 cure specimens thus differing by examining a number of individuals, 

 and keep both kinds for comparison. Sketch dorsal, lateral and 

 ventral views of each (especially in the regions of difference). 

 External Features. Study the following points : 

 i. The regions of the body. 

 Head; thorax; abdomen. 



What are the signs of segmentation in these three regions ? 

 Where is it most clearly indicated? Where are the 

 segments most similar? 



