1899] MICROSCOPICAL JOURNAL 243 



either disappeared altogether or have shrivelled up into a 

 very small compass, being of no further use to the little 

 creature. The last mentioned are, I believe, the larval 

 stage of Limnesia histrionica. So little is known at 

 present about the larval atages of water mites, that it is 

 almost impossible to name the species correctly from the 

 larva3. After having spent sometime in the state just 

 mentioned they become free swimming, with eight legs, 

 and are now very much like the adults, so much so, that 

 you can now tell with tolerable certainty the species to 

 which they belong. 



All of the members of the genus Arrenurus are hard 

 skinned mites, the males only have tails, the females being 

 without these appendages. Arrenurus tricuspidator 

 (Muller), is a very brilliant red mite. It can easily be 

 recognized by the peculiar formation of its tail. Ar- 

 renurus emarginator (Muller) is a very large red mite. I 

 believe we shall have several more red mites to place in 

 this genus later, because I have several red females that I 

 cannot name until the males are taken. 



The genus Hydrachna contains soft-bodied mites, which 

 can be recognized by the mouth organs projecting as far 

 forward as the palpus. In this genus we have two red 

 mites. H. cruenta (Mull.), is easily known by the patch 

 on the dorsal surface behind the eyes. 



The genus Hydrodroma is also represented by two red 

 mites, also distinguished for the patch on the dorsal sur- 

 face. The genus NessBa has several red mites. Of course, 

 all fresh-water mites are not red, all colors being repre- 

 sented in these beautiful creatures more or less, but I 

 have said enough to show that instead of anyone captur- 

 ing the common red water mite it is much more likely 

 that he has only captured a mite of a common color. — 

 Illustrated Annual. 



