252 



caught in large numbers in shaded drains, under 

 bridges, in outhouses, etc., and excellent material is in 

 this way easily got. Identify the species of Culex 

 that is infected. 



(iii) For the method of feeding mosquitoes on 

 birds' blood, vide p. 95. 



Twelve to fifteen hours. Vermiculi in all stages 

 of development are found in the stomach ; a conical 

 projection arises from the fertilized gamete. This 

 gradually elongates, forming a long, curved, oval body, 

 the complete vermiculus. The protoplasm is vacuo- 

 lated, and a nucleus (chromatin) is readily shown by 

 staining (Romanowsky). 



The proteosoma vermiculi are larger and more 

 slender than those of halteridium. 



Development of Zygotes (one or two days). The 

 vermiculi have disappeared, but in the stomach wall 

 are now found transparent, spherical, pigmented 

 bodies. 



Three to four days. The zygotes have increased 

 in size, and sporoblasts appear in their interior. In 

 the larger forms, signs of further division are seen 

 (striation), formation of sporozoits. 



Development of Sporozoits (nine to ten days). By 

 this time the sporozoits have reached the salivary 

 glands. Somewhat earlier they can still be found 

 amidst the thoracic muscle. Earlier still, they can be 

 pressed out of the ripe oocysts in the stomach wall. 

 The sporozoits occupy chiefly the middle lobe of the 

 gland (Koch). 



Black Spores are found in the larger zygotes. 

 They also occur free in 'the thoracic region (or, 

 possibly, in the gland substance). They are brownish- 

 black, curved, sausage-shaped bodies, suggesting a 

 mycelial nature. It is believed by Grassi that they 



