MICROSPORIDIA — PARASITIC IN MOSQUITOES 157 



less distended thorax, than the majoritj^ On microscopical 

 examination, the former proved to be infected by a microsporidian 

 parasite represented b}' numerous very conspicuous spores. 

 Hence, all the specimens were subjected to careful examinations, 

 either in fresh smear or in section preparations. 



The results of the examination are as follows (table, pp. 158 

 and 159) . 



As will be seen from the above, out of thirty-eight larvae ex- 

 amined, six were infected by the present parasite. Thirteen 

 pupae examined were free from the infection. One of nine adult 

 mosquitoes examined showed a few spores in fresh smear, while 

 the rest were uninfected. Judging from the results of the exam- 

 ination recorded above, showing that almost all of the infected 

 larvae manifested more or less heavy infection, the parasite ap- 

 pears to exercise a mortal effect upon the host, and the infected 

 larvae die before completing their larval life. Most careful 

 examination of the sections of the other larvae failed to reveal 

 any with slight infection. As the habit of the larvae shows, 

 those infected either swallow^ed a large amount of infected tissue 

 of the larva dead from the infection and underwent decay at 

 the bottom of the pool, so that the heavy infection resulted in 

 comparatively short time, or became infected when quite young. 

 Although the writer did not encounter any larva slightly infected, 

 there would most probably be some larvae which, having only 

 been infected to a slight degree or at later days of the larval 

 stage, may be able to transform into pupae and even into adult 

 mosquitoes. In order to solve these questions the writer went to 

 the place on November 17, only to find that heavy and continu- 

 ous rain in the latter part of October connected the pool with 

 the main stream, producing a suitable place for small fishes, so 

 that not a single mosquito larva was found. 



The following description of schizogony and sporogony is the 

 summary of observations on a single section preparation and a 

 number of smears. 



The youngest schizonts found in the adipose cell are rounded 

 bodies, each containing a deeply staining nucleus (figs. 1, 2). 

 They are about 4 to 5^ in average diameter. The nucleus is usu- 

 ally located in the center. These schizonts are grouped in the 



