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Transactions of the Society. 



food to support the insect during the long period (often many 

 months) occupied in rearing her new colony. 



It now became clear that the worms could not satisfactorily 

 emerge from their hosts and continue their existence if left on 

 ordinary dry earth. I therefore varied the experiments as follows : 

 I took a L. alienus mermithogyne that had been dead for twenty- 

 four hours without the Mermu having emerged, and placed it in a 

 saucer containing a little earth covered with water. In less than 

 ten minutes the worm had emerged and was sluggishly lashing to 

 and fro in the water, keeping up these movements all day. 



In the evening I drained off the water in the saucer, and the 



Fig. 1. — Mermithogyne of Lasius alienus. 



worm then spent hours trying to bore into the wet earth, which 

 was not deep enough to allow its whole body to be buried at one 

 time. 



When the earth dried up the worm became motionless, but 

 flooding it with water was sufficient to arouse it to renewed 

 activity. On August 13 the remaining L. fiavus female died. I 

 placed the body, as before, on earth barely covered with water, 

 and the worm, a very small one, emerged with some rapidity, and 

 at once began burrowing in the wet earth. From this time till 

 the end of November, more than three months, this Mermis re- 

 mained alive, increasing somewhat in size. After the first few 



