SI X IN PROTOZOA 207 



Nowlin (1922) reported that ;i grcgarinc {Schneideria sp.), found 

 in the flv Sc'huct copro^ihila goc^ no further in its development in the 

 hirval stage of the host than the fullv^ grown trophic stage (gamont); 

 in the pupa, the ganionts unite in pairs, become encysted, and begin 

 sporulation. In the adult, sporulation is completed. Whether any of 

 these changes in the life cycle are influenced by molting or other 

 hormones of the host is, of course, unknown at the present time, but 

 the correlation may have some well-defined host-relationship basis. 

 Shortt and Swaminath (1927) reported a somewhat similar relation- 

 ship between Movocystis inackki and another dipteran host, Fhle- 

 hotovnis argan'ipes. In this case sporulation did not begin until the 

 host became adult. 



As shown by Wenyon (1911) and later by Ganapati and Tate 

 (1949), the development of the gregarine Lankesteria czilicis in mos- 

 quitoes shows similarities to that of the species cited above. Trophic 

 development takes place in the gut of the larva, and union of gamonts, 

 cyst formation, and sporogony take place in the malpighian tubules 

 of the pupa. Only spores are found in the adult. 



Hentschel (1926) reported a correlation between the develop- 

 ment of the acephaline gregarine Gonospora varia, with the sexual 

 development of its host, the polychete worm, Andoninia (Terraw- 

 his) teinaciilata. The coelomic parasites live among the developing 

 genital products of the host and complete their life cycle at the time 

 of sexual maturity of the worm. Occasionally gregarines are present 

 in segments which do not contain gonads. In these segments the 

 parasites are unable to complete their full life cycle, remaining small 

 and apparently unable to produce spores. Hentschel suggested that 

 the host gonads may produce a hormone or other substance which is 

 essential to the growth of the gregarines. The same author (1930) 

 reported a somew^hat similar relationship between Gonospora areni- 

 colae and its host, Arenicola ecaudata, except that the correlation 

 was not so close as for G. varia and Audouinia tentacidata. 



For those gregarines which have two hosts, as do members of 

 the family Porosporidae (including Neviatopsis, Fig. S), there is a 

 correlation between stages in the life cycle and the change of hosts; 

 this is true in other cases of two-host development, as in the coccidian 

 Families Aggregatidae and Haemogregarinidae and in the Order 

 Haemosporidia. It is fair to assume that, when any transmissible stage 

 in the cycle leaves one of the alternative hosts, transfer to the other 



