HAMOSPORIDIA 159 
“ Contrarily to the fungi, announced previously by the same authors, these 
yeasts do not become pathogenic to the culicids; neither can one, according to 
them, attribute any réle whatever in the aptitude of Stegomyia calopus for 
transmitting yellow fever. 
“ Nevertheless the study of these yeasts is not devoid of interest : the spherical 
or irregular masses formed by these yeasts, which one encounters in the large 
air-sac of the culicid, may be easily taken, upon superficial examination, for 
sporozoans, and the authors are not far from supposing, as we shall see farther 
on, that these yeasts were taken by the Americans Parker, Beyer and Pothier, 
for one of the stages of the parasite which they described under the name 
Myzococcidium stegomyie. It is well to indicate, now, the possible errors of 
interpretation to which the encountering of these yeasts, parasites of culicids, 
can give place. 
“ Schaudinn, in his remarkable work, interprets in a wholly individual man- 
ner the réle of these yeasts, which he nearly always found in the diverticula of the 
stomach (air-sac, sucking stomach, food reservoir) of the numerous culicids 
which he dissected in the course of his beautiful researches. According to him 
these yeasts have a purely physiological réle: by his investigations he has been 
led to conclude that the irritating effect of the bite of Culex is due, not alone, 
as it had been thought up to now, to the saliva secreted by the salivary glands, 
but as well to the combined action of gas and diverse products, secreted by the 
yeasts of the cesophageal diverticula. We will not follow the author in his very 
concise demonstration of this réle of the yeast parasites in any physiological way ; 
we have only to mention this original interpretation in passing, which shows us 
how much all these questions of the parasites of culicids need to be seriously 
studied. We see in fact, on the subject of these yeasts of the stomach of the 
mosquito, three authors, studying them successively in different countries, 
Schaudinn in Germany, Parker, Beyer and Pothier in Mexico, Marchoux, 
Salimbeni and Simond in Brazil, and each one of them attributing a totally 
different interpretation from the viewpoint of their parasitic réle.” 
ANIMALS. 
PROTOZOA. 
Parasites of mosquitoes belonging to the Sporozoa and Flagellata have been 
described by many authors. Among the Sporozoa are Myxosporidia, Hemo- 
sporidia and Gregarinez. To the Hemosporidia belong the malarial and other 
blood parasites of mammals and of birds. These are grouped in the family Plas- 
modide and, as is well known, have a life-cycle which necessitates two hosts. The 
agamic phase is passed in the blood of a vertebrate, the sexual phase in some 
blood-sucking insect. These parasites are discussed in a later chapter, in con- 
nection with malaria (p. 188). A nearly related group of Hemosporidia is the 
family Hemogregarinide, a large proportion of which live in cold-blooded 
animals (reptiles, batrachians and fishes) but also some in warm-blooded 
animals (mammals and birds). It was in a species of this group, an Hemopro- 
teus from the crow, that MacCallum was the first to prove the existence of sexual 
phases in the Hemosporidia. Several Hemogregarinide are known to be 
transmitted by mosquitoes. According to Schaudinn, Hemoproteus noctue, a 
blood-parasite of owls, is transmitted by Culex pipiens. Another species, 
Hemoproteus danilewskyi, and probably still other species, all living in the blood 
