178 ANIMAL PARASITES AND MESSMATES. 



We often find in summer in puddles of water, tliin 

 worms, which are sometimes a foot long, resembling a 

 violin string, and have for a long time puzzled natural- 

 ists. They are known by the name of Gordius, and have 

 lately been very carefully studied, both with reference 



to their organization, to 

 their mode of life, and 

 their development. We 

 give here the figure of a 

 Gordius of the natural 

 size. The Mermis, like 

 the Gordius, passes its 

 youth in the body of cer- 

 tain insects, and leaves 

 its living cradle to 

 scatter its eggs abroad. 

 In this case, the embryos 

 themselves go to seek for 

 their host, and unlike the 



Fig. 40. — Gordius aquaticus, natural size. 



ichneumons, they use 

 them with moderation. The life of the host is never 

 compromised, and no functional disturbance is observed, 

 notwithstanding the enormous size of the worm. 



The Mermis is especially found after a heavy 

 shower; some kinds of Filaria are also more common 

 when it rains. Under the title of " Notes on the Appear- 

 ance of Worms after a Shower of Bain," I communicated 

 to the Academy of Belgium some observations on these 

 creatures, and these observations were recorded in the 

 bulletins. 



Some years ago they brought me one morning, after 

 a shower of rain, a quantity of worms, four or five inches 



