THE FLEAS 27 



EXERCISE 15a 



THE FLEAS 



ORDER SIPHONAPTERA 



Anatomical Study. 



In order to find the following characters two species of fleas 

 should be used, namely, the human flea (Pulexirritans), and the 

 dog flea (Ctenocephalus canis). Note the entire absence of 

 wings and the characteristic laterally compressed condition of 

 the body ,with legs strongly developed for springing. 



a. Legs; observe the greatly elongated coxa, and other seg- 

 ments. 



b. Mouthparts; composed of sharp piercing structures; a de- 

 tailed study of which may be omitted here. 



c. Antenna; short, three-segmented, usually sunken in a pit. 

 The terminal segment is swollen and annulated. 



d. Combs; rows of spines on the head (oral), and thorax (pro- 

 notal), forming combs (ctenidia) are used to separate the fleas of 

 the family Pulicidae into the combed and non-combed species. 

 The number of spines in each comb is also useful for classifica- 

 tion. In the dog flea notice the two rows of combs and count the 

 number of spines in each. 



e. Eyes, which may be present or absent, are of a simple type. 



f. Examine and draw a specimen of flea larva. 



g. Examine and draw specimens of flea eggs. 

 Draw one example of each species of flea. 



