62 E. H. STRICKLAND 
GENERAL HOST RELATIONSHIPS OF THE MICROSPORIDIA 
By far the greater number of known cases of Microsporidian 
infection have been recorded from fish, though infection of crusta- 
ceans, particularly of crabs, is not infrequent. In insects about 
forty cases of infection have been recorded. . A great number of 
the descriptions, however, are very incomplete. All tissues of 
the host are liable to be the seat of infection, though in fish the 
muscles are the most favorable, while in insects the fat body 
usually suffers. 
The tissue-infecting forms fall into two categories: (1) Con- 
centrated, in which the adjacent tissues form a membrane around 
the trophozoite, or the trophozoite itself is limited by a definite 
membrane; (2) Diffuse, in which the protoplasm of the parasite 
and host cells becomes indistinguishably mingled, till the tis- 
sue is found to be infiltrated with vast numbers of spores 
(Nosematidae). 
As a general rule, infection by these parasites is not fatal to 
the host though its vitality is much impaired. When larvae of 
insects are infected the parasite is often able to pass over into the 
adult and in the case of pébrine is capable of infecting the ova, 
so that the disease is transmitted to the next generation. 
Insect hosts of Microsporidia 
The following list of the insect hosts of Microsporidia is par- 
tially adapted from Minchen’s work (’03) on Sporozoon hosts, 
with additions from more recent literature. Doubtful, or incom- 
pletely described forms have been in most cases omitted. 
DIPTERA 
Anopheles maculipennis, larva.......Thelohania legert Hesse (04) 
Chironomus sp., larva...............Nosema chironomi L. and 8. (’08) 
Corethra sp play acne. one eee Nosema corethrae L. and 8. (’08) 
Limnophila rhombia, larva.......... Thelohania janis Hesse (’03) 
Pachyrhina pratensis, larva.......... Glugea stricta Monz 
Simulium ornatum, larva............Glugea varians Legér (’97) 
Simulium venustum, larva........... [Nosema] Glugea simulii L. and S. (’08) 
Simulium ochranum, larva...........[Nosema] Glugea simulii L. and S. (08) 
Simulium bracteatum, larva\ | __. J Glugea bracteata sp. nov. 
Simulium hirtipes, larva { \ Glugea fibrata sp. nov. 
Simulium vittatum, larva............ Glugea multispora sp. nov. 
Stegomyia fasciata, larva and adult Nosema sp. Simond (03) 
Stegomyia fasciata, adult............Nosema stegomyiae L. and 8. (’08) 
Tanypus varius, larva...............Thelohana pinguis Hesse (’03) 
