THE SQUASH BUG AND THE HARLEQUIN CABBAGE BUG 59 



XVIII. THE MOUTH PARTS AND LIFE HISTORY OF THE 

 SQUASH BUG AND THE HARLEQUIN CABBAGE BUG 



Materials. Squash bugs and harlequin cabbage bugs, magnifier, 

 potassium hydrate, pins. 



Directions. (The squash bug is an ill-smelling, dark-brown 

 insect a little less than of an inch in length. It is common in gar- 

 dens on squashes, melons, and cucumbers, and the adults may be 

 easily secured during the summer. They should be placed in al- 

 cohol or formalin. 



In the Southern states the harlequin cabbage bug may be used 

 instead. This bug is known as the "calico back," or "terrapin 

 bug," and is very injurious to cabbages, radishes, and mustard. 



Better than either of these, for a study of the mouth parts, is the 

 dog-day harvest fly, or cicada.) 



A. EXTERNAL FEATURES. Head. Note the compound 

 eyes. They are not so large as those of the locust or but- 

 terfly. Note the simple eyes. How many are there and 

 where are they ? Note the antennae. How many segments 

 in each one ? How do they differ from those of the butter- 

 fly ? Note that the head slopes greatly in front. 



Mouth parts. Note a sharp pointed, immovable, upper 

 lip. At the base of this arises a slender beak that is found 

 pointing backward beneath the thorax between the bases 

 of the legs. Take off the head and mount it on a slender 

 pin, which can then be stuck into a piece of cork to facilitate 

 handling. Examine the beak with the low objective or a 

 hand lens. Is it jointed ? How many segments are there ? 

 With sharp pointed needles pick the beak apart. Fresh 

 specimens or those preserved in alcohol may be used, but 

 better than either are dried specimens, the heads of which 



