MICROSPORIDIA PARASITIC IX MOSQUITOES. 113 



into light some phases of the development of the protozoon which 

 \\i-re not recognized in the scant material of 1919 and which now 

 lead me tn place the microsporidian in the genus Stem pel! ia. 



Tin- present paper deals with the findings thus made with 

 >](( i.il reference to the development of the microsporidian 

 Martini; with an experimental infection and is intruded to 

 supplement the observations published before. 



MATERIAL AND METHODS. 



The h<>-! larva?, Culex territans, were found breeding in an old 

 boal filled with rain water on Conwango River at \\"arreii, 

 I 1 - ;:ii-> 1\ aiiia. On two occasions, July 5 and 10, i)jo, j<)o larva- 

 were collet '<-d and examined microscopically, of which 43 were 

 found to be infected by the microsporidian. 



The material was studied in fresh as well as fixed and -Mined 

 Miie. 11- and in section preparations. For fixation, Schaudinn's 

 mixture was mainly used; for staining, Heidenhain's iron 

 ha -in. t ic. \\lin or Gicmsa's stain was used as in previous stin! 

 A leu < liemsa-stained preparations were decolorized and stained 

 \\ith Heidenhain's ha-matoxylin, although the reverse was uoi 

 at tempted, iii order to compare the effects of staining by the two 

 method-. It may be worth while to state here that methylene 

 Mm- M.I', seems to be a suitable stain for the spores. On July 7, 

 [920, 1 subjected a number of spores to mechanical pressure on 

 a slide, added one drop of a strong aqueous solution of methylene 

 blue and sealed with a vaselined coverglass. An examination 

 of i his preparation in the summer of 1923 showed that the spore 

 membrane had not shrunk and that both the polar capsule and 

 the -pi'i-opl.isni in the spores which escaped the pressure were 

 m. -l di-tinrtly visible (Figs. 4 j, &). 



Sinee l-'ontana was not carried on the trip, smears of pressed 

 spores were either stained with Giemsa's stain or treated with a 

 mixture !' 1 ,ug< -1's solution and gum arabic. Some of the smeai > 

 \\ere kept air-dry, however, and stained later with Fontana. 



THE INFECTION EXPERIMENT. 



In order to determine the changes which the spores of the 

 miero-poridiaii undergo in the digestive tract of a new host larva 

 when taken into it with food and if possible, the way with which 



