348 GUIDE TO CALIFORNIA INSECTS. 



serted in the thorax to the right of the median line and should emerge, in most 

 cases between the middle and hind legs. One fourth of the length of the pin 

 should be above the insect. 



See that dirt that might render the study of the specimen difficult is re- 

 moved. If the legs are retracted extend them and if the legs or antennae 

 are unusually long bring them up towards the body so that they may be in 

 less danger of being broken off. Pull out the tongue in the case of bees 

 that the palpi may be seen. It is generally desirable to attempt to deter- 

 mine any unknown insect at pinning time to learn what parts must be 

 studied so that care may be taken to keep these exposed. 



Small insects may be mounted by gluing them to the point of paper tri- 

 angles These should be not over 1 cm. long nor over 2 m.m. wide at base. 

 The under part of the left side just above the legs should receive the triangle 

 point, the insect being at right angles to the triangle. Before beginning to 

 mount a quantity of triangles should be cut and pinned ready for use. 



Velvet mounts are undoubtedly the most convenient method for small in- 

 sects. Cut white velvet into pieces one inch by three, lay a piece on a 

 microscope slide pile up, arrange the specimens on the velvet and then lay 

 another slide over them fastening the ends with gummed labels. Mount 

 many specimens of each kind, both side up, and see that all significant 

 structures are exposed. Other specimens may be added by breaking the seal 

 at one end and carefully lifting the upper glass. 



DRAWING. 



The only way to effectively study complicated structures i^ by drawing 

 them, and the first thing a student should learn is to draw accurately. Ac- 

 curacy in drawing is almost wholly a question of learning to see and appreci- 

 ate proportions. One sees the detail and if a feature of the detail is drawn 

 first it will almost invariably be out of proportion. It will not look right but 

 one is at loss to see wherein it fails to correctly interpret the object. 



To draw a grasshopper side view for instance proceed as follows: 



1st Decide and mark on the paper the total length of body. 



2nd Draw the dorsal line locating the proportion the head, prothorax and ely- 

 tra contribute to this line. 



3rd Locate the main ventral line, comparing the width of the thorax with 

 the dorsal length of the prothorax. 



4th Locate the hind leg noting tne position of the base by its direction from 

 the hind angle of the pronotum, the angle at which it crosses the dorsal line, 

 the length as compared with the elytra, and by the direction the tip of the 

 leg lies from the tip of the wing. 



.5th Locate the divisions between the abdominal segments. 



6th Now proceed to work in the detail, locating the minor points as needed 

 in the same manner as above. 



