410 THE CANADIAN ENTOMOLOGIST 



their life histories were worked out. The appearance of parasi- 

 tised larvae was similar to thql of the specimens, found in Spring, 

 containing other Myxosporidia S.L. The life history of the organ- 

 isms is, in brief, as follows: a spore is taken into the alimentary 

 tract of a very young larva. From this escapes an amoeboid germ, 

 which passes between the cells of the mesenteric epithelium, and 

 thus gets into the body cavity. Here it attacks, and enters, a cell 

 of the fat body, where it grows with great rapidity, soon bursting 

 the cell and living free life in the body cavity of its host. It is now 

 termed a trophozoite, and consists of a multinucleated mass of proto- 

 plasm. As the trophozoite matures, a small clearly constricted 

 globule of protoplasm collects around each of the numerous nuclei, 

 to form a spherical sporont. The single nucleus of the sporont 

 undergoes three (or more in some species) divisions, thus forming 

 eight nuclei, which in time become the centres of eight small bodies 

 known as sporohlasts. Around each of these sporoblasts is secreted 

 a thick shell, which activity is accompanied by a complicated in- 

 ternal development. This converts the sporoblast into a mature 

 spore, which is capable of spreading the infection, which liberated 

 in the water by the death and subsequent decay of its host. 



It is believed that infection by this class of parasite can be 

 accomplished only in the earliest stages of larval life, before the 

 peritrophic membrane lines the entire surface of the mesenteron. 

 The latter, it would seem, is the only part of the alimentary tract 

 which would not resist the attacks of an unarmed germ. A fuller 

 account of this exceptionally stout peritrophic membrane, and its 

 development, has been published by the writer ('13). In this 

 paper, also, the three Glugeid species discovered as parasites of 

 Simuliid larvae were described. 



It will be seen, from the above descriptions of the various 

 parasites of Simuliid larvae found around Boston, that they are 

 very conspicuous, and would readily attract the attention of an 

 observer. Notwithstanding this fact, there are no other records 

 of their occurrence in North America. This would appear to 

 indicate that, in those sections of the country where species of 

 Simulium are most abundant, these parasites do not exist, for in 

 these places careful studies of the larval stages have been made by 

 several observers. A Glugeid was described from the European 



