STUDIES ON MICROSPORIDIA PARASITIC 

 IX MOSQUITOES. 



V. FURTHER OBSERVATIONS UPON StempelUa (Thelohania) magna 

 KUDO, PARASITIC IN Culex pipiens AND C. territans. 1 



R. KUDO, 



DEPARTMENT OF ZOOLOGY, UNIVERSITY OF ILLINOIS. 



CONTENTS. 



PAGE 



Introduction 1 1 2 



Material and Methods 113 



The Infection Experiment 113 



Schizogony Il8 



Sporogony 1 2O 



The Spore 122 



The Relation between the Parasite and the Host 126 



Summary 126 



Papers Cited 126 



INTRODUCTION. 



In the autumn of 1919, I chanced to observe at Urbaria, 

 Illinois, six larvae of Cnlex pipiens which were infected by a 

 microsporidian and named it Thelohania magna (Kudo, '20). 

 Since the prospect of obtaining additional material was small at 

 that time, I ventured to summarize the results of my observations 

 made upon "a single section preparation and a number of 

 smears" of the host larvae in a paper ('21). 



In the following year, I found at Warren, Pennsylvania, some 

 forty-three larvae of Culex territans which harbored an apparently 

 similar protozoon, whose effect upon the host mosquitoes was 

 the subject of another paper ('22). This material from Pennsyl- 

 vania was far more abundant than the previous collection, and 

 enabled me to conduct an infection experiment. The observa- 

 tions in the temporary field laboratory and subsequent micro- 

 scopical studies of a large number of preparations have brought 



1 Contributions from the Zoological Laboratory of the University of Illinois, No. 

 2.S4- 



112 



