1905.] 



NATURAL SCIENCES OF PHILADELPHIA, 



161 



the cytoplasmic mass, which may thus become a thin shell, or even 

 wholly wanting at the two ends of the spore. There is an evident 



Fig. 5. 



membrane or shell in the mature spore, the average length of which is 

 5 microns. 



The reason for regarding these bodies as spores is the fact that they 

 occur in the alimentary canal of the host, both before and behind the 

 openings of the Malpighian tubules. 

 In the former position they were 

 seen to lie close against the epithe- 

 lial cells, but none of my material 

 showed any of them en route to en- 

 trance. 



Perhaps the most striking phe- 

 nomenon exhibited by this parasite 

 is the abundance wdth which it 

 occurs. Fig. 6 shows the cross-sec- 

 tion of a tubule, wherein the para- 

 sites come near to occluding the 

 entire lumen. This is a quite char- 

 acteristic condition. It would seem 



that so complete a blocking up of the tubule should produce dis- 

 turbances in the economy of the host. Yet the tubule epithelium 

 was throughout, to all appearances, wholly normal. 



Fig. 6. 



11 



