TRUE GUESTS, ECTO- AND ENTOPARASITES. 



421 



it to be an egg-laying " parthenogenetic female." Since the publication 

 of my paper (19010?) he has reexamined this specimen and several other 

 worker ants with larger gasters and traces of ocelli in his collection and 

 has found them to contain Mennis. Besides the two species already 

 mentioned, he has recorded the occurrence of mermithergates in Odon- 

 tomachus Iiccinatodes and chelifer, Neoponera inversa, Ectatomma 

 tiibcrculatiun, Pachycondyla fuscoatra and Paraponcra clavata. These 

 pathological forms therefore occur rather generally, at least in the 

 neotropical Myrmicinae and Ponerinae. 



It is interesting to compare the modifications induced in their 

 respective hosts by the parasites Orasema, Mennis and Lomechusa. 



FIG. 254. Parasitism of Mennis in Pheidole coininutata. (Original.) A. Nor- 

 mal worker of Pheidole coinmntata ; B, mermithergate, or worker containing Mennis 

 parasite which it possessed as a larva ; C, same, lateral view. 



While the effects in all three cases are wrought through a withdrawal 

 of nourishment from the developing larvae, each of the parasites adopts 

 a different method. Thus the ectoparasitic Orasema larva extracts 

 important juices from the body of the Pheidole larva directly and with 

 great rapidity, thereby reducing its host to a mere skin, which, though 

 still able to pass on to the pupal stage, no longer possesses sufficient 

 substance or vitality to reach the imaginal stage. The Mennis larva 



