66 ARTHROPODS 



The Head. — (i) Study the front part of the head. 

 How many ocelli f How are they arranged? Note the an- 

 tennae. Are they like those of the grasshopper ? How ma:ny 

 segments? Do you notice anything peculiar about the sur- 

 face of the head ? 



(2) Find the following mouth parts: — a, A thin small 

 •Rap, the labrum. Is it movable? b, A pair of strong jaws, 

 or mandibles, hard and black at the tip. For what are these 

 used ? c, A proboscis, which will be found bent back under 

 the mouth. Remove it with the tweezers, being careful not 

 to injure any of the parts. Spread the parts out and find 

 the central, long, hairy tongue, the short labial palpi close 

 to the tongue, and the long, slender blades, the maxillae. 



Get these in the right position on a slide, under a cover 

 glass, and place under the low power of the microscope. 

 Make the following drawings : 



The front of the head (XS). 

 The proboscis (Xio). 



The Thorax. — ( i ) Observe the enormous develop- 

 ment of the thorax. Is such a thorax of special value to the 

 bee? 



(2) Study the bee in flight. How are the wings dis- 

 posed when flying ? When at rest ? Are both pairs of wings 

 used in flight ? Look for a small wing cover in front of the 

 fore wing. It is the tegula. To what in the beetle is it ho- 

 mologous? Study the method of attachment of the wings. 

 Remove one of the front and one of the hind wings. 



Are the wings separate, or fastened together? 



Study the venation of the wings. Do you find the costal, 

 median, and internal areas? Is the venation the same in 

 both pairs of wings? 



