158 



PARASITOLOGY. 



arranged, point backwards. The booklets are 

 very small and resemble, in shape, those of a cat's 

 claw. The posterior half of the female is attenuated 

 until it is no larger than a knitting needle; the female 

 is eight to twelve inches long, the male three to four 

 inches. 



Life Cycle.— The fe- 

 male is oviparous; the 

 eggs are oblong and 

 contain fully developed 

 embryos, in a few days 

 after they have passed 

 to the ground with the 

 feces; if they are in- 

 gested by the intermed- 

 iate host, which is the 

 larva of the May bug 

 ( white worm or grub 

 worms) they soon hatch 

 in its digestive tract ; 

 this embryo is very 

 small and provided 

 with four small hook- 



Fig. 62 — ECHINORHYNCHUS GiGAS. 



Cephalic extremity showing globe- 

 shaped proboscis and six rows of 

 booklets. 



Photomicrograph, 1\% 



lets with which it burrows through the intestinal wall 

 and becomes encysted in the abdominal cavity ; when 

 this cyst matures it contains the fully developed larva, 

 which retains its vitality during the existence of the 

 larval worm and has been noted still alive after 

 metamorphosis into the perfect insect; it is possible 

 that other invertebrates may act as an intermediate 

 host; if the pig eats these white worms or May 

 beetles containing the encysted larva, the young echi- 

 norhynchus is set free by the process of digestion 



