Vol. XXlii] ENTOMOLOGICAL NEWS 223 



gametoblast the nucleus divides into a number of parts (the 

 number depending on the species of parasite) which arrange 

 themselves near the wall, and from each of which is developed 

 ;t tlagellate microgamete. These are freed from the resting 

 cell and being motile may find a macrogamete which one of 

 them enters and fertilizes. The fertilized macrogamete now 

 becomes elongate and ovoid and is termed the ookinete, or 

 wandering cell. It penetrates the wall of the stomach, and, 

 passing through the epithelium, it encysts just under the base- 

 ment membrane. These cysts occur mostly on the posterior 

 iwo-thirds of the dilated part of the stomach. The resting 

 cell or oocyst increases greatly in size as by nuclear division 

 it produces many sporoblasts which in turn develop into 

 snorozoites. When completely matured the cyst bursts liber- 

 ating the sporozoites in the body cavity of the mosquito. 



They are carried around in the blood currents, and, pene- 

 trating the salivary gland, surround the central canal down 

 which they finally pass with the salivary secretion. The mos- 

 quito in biting its victim, injects them into the blood and the 

 life-cycle is complete. 



The nature of the diagram necessitates inaccuracies in 

 structure such as for example the exaggerated length of the 

 dilated portion of the stomach. On the other hand since not 

 all mosquitoes are capable of transmitting the parasite, I have 

 included such characteristics of Anopheles, the malarial bear- 

 ing mosquito, as could be placed in such a diagrammatic rep- 

 resentation. 







A STATION FOR INSTRUCTION AND RESEARCH IN BIOLOGY will be main- 

 tained by the University of Michigan from July 2 to August 23 in- 

 clusive, 1912, near the Bogardus Engineering Camp of the University 

 on a tract of land stretching from Douglas Lake to Burt Lake in 

 Cheboygan County, Michigan. Since the number of students that can 

 be accommodated is limited, immediate registration is necessary to 

 insure admission and no registration will be accepted if received after 

 June ist. Applications for admission should be addressed to Professor 

 T. E. Rankin, Secretary of the Summer Session. Ann Arbor, Mich. 

 Among the courses offered is one on tlir Natural History of Insects 

 by Professor Frank Smith and Mr. Paul S. Welch, of the University 

 of Illinois. 



