1921. Phibbs. — Variations in Spines of Larva of Hypoderma. 55 



hardly to be distinguished from the horny platelets of the 

 cuticle. Various stages of development between plates 

 and spines may be observed. 



^oO^ ' Oq 



Fig. 3. Comparison of spines on the latero-ventral areas of the right 

 and left sides of a single H. bovis fourth-stage larva, x 20. The numbers 

 indicate the segments. 



The eighth latero-ventral area was chosen for comparison 

 in ten specimens. The results of this comparison are indi- 

 cated in fig. 2. All the spines are simple ; that is to say 

 each spine has only one point. In number they range 

 from' one (j.) to eleven (a). In one or two cases true spines 

 can hardly be said to exist on the area at all (k.). The 

 spines are irregularly arranged in a single line, with, in one 

 or two cases, an odd spine below. In size and shape the 



