26 VIGNETTES FROM INVISIBLE LIFE. 



the word " Tyro " suggests ; as its disuse may be 

 ascribed to an advance in organisation in another 

 direction, or an environment which rendered it no 

 longer necessary ; or even it may be the result of 

 accident in some remote ancestor, who neverthe- 

 less managed to live and perpetuate the injury to 

 its descendants. 



Instead of making bricks and building a home, 

 M. tyro secretes a glutinous covering, in which it 

 moves and has its being. This is of rather a loose 

 texture, and may be regarded as approaching the 

 Limnias, described in our next, or to that of the 

 Moscules in No. V. To return, " Melicerta tyro 

 is a Melicertan with a gelatinous sheath very like 

 that which invests the Floscules, and yet with a 

 distinct character of its own." Its trochal disc 

 is four-lobed like that of M. ringens, but with more 

 of a "butterfly" character when expanded, and 

 having two long antenna. Moreover, the eyes even 

 in the adult form are more readily seen than in 

 M. ring ens, or the Floscules. All things considered, 

 it does not seem to be undergoing a process of de- 

 terioration, notwithstanding the loss of its brick- 

 making faculties. 



