372 Transactions of the Society. 



of M. pachi/soma (of which only the late parasitic larval stage is 

 known), except the much greater thickness of the body (0'72- 

 1 '26 mm.). 



In the recorded cases of infection of ants by supposed 

 MermithidsB, the worms themselves do not appear to have been 

 adequately described. In no case, we believe, have the larva? been 

 kept alive and allowed to reach maturity. It is not improljable, 

 therefore, that some of these cases may be referable to Mermis 

 tnyrm ecophila. 



