362 Transactions of the Society. 



out the hole, and it does not exist in any of the more numerous 

 specimens from the other coLinies previously examined. 



There is another case of malformation in this colony, occurring 

 in a normal female. It consists of a semicircular excision in the 

 apical border of the third segment of the gaster, and is probably 

 unconnected with the parasite. 



I dissected a number of full-grown female larvae and also 

 several pupa? from this colony, but failed to find any trace 

 of the worm. These mermithogynes were very active, often 

 assisting callow ants to emerge from their cocoons, and were 

 also very ravenous, devouring Hies that I put into the nest, and 

 also crippled and damaged pupse and callow^s, besides always 

 asking the workers for food. Occasionally one would be seized 

 with a kind of paralysis, lie on its back with legs and antennee 

 extended and twitching, and a movement of the worm inside the 

 gaster could be seen at the same time. Such ants usually recovered, 

 but in one or two cases they died. After the emergence of the 

 worms the ants became very active, but their death was only 

 •deferred a short time. 



By constantly placing each mermithogyne, as soon as she 

 became restless or died, on damp earth in a pan I succeeded in 

 obtaining thirty-seven worms, which I transferred to a larger and 

 deeper vessel with damp earth. At the beginning of November 

 they were all still in the larval stage, the outer skin being very 

 distinct, but the genital organs Avere beginning to develop. By 

 Nov. 20 four had cast their larval skins, the operation consisting 

 in piercing the skin a short distance from the head and then peel- 

 ing off the skin by burrowing into the earth. When the earth 

 became dry most of the worms came to the surface and remained 

 motionless, with about a third of the body projecting in a coil in 

 the air. A sprinkling of water invariably caused them to descend 

 below the earth again. The first egas were noticed in the uteri 

 on Dec. 5. The problem of keeping them alive began to be 

 acute about this time, mould making its appearance on the surface 

 of the soil. Sand was tried in place of soil, but rapidly became 

 matted with mould and destroyed the worms. Finally, the best 

 method was found to be to keep them in small flower-pots with a 

 layer of plaster of Paris at the bottom to close the hole. The 

 terra-cotta being porous allowed drainage to take place, so tliat 

 the earth remained very nearly free from mould, and the only 

 drawback was the necessity of frequent watering to replace the 

 evaporated moisture. Four or five worms had assumed a Ijrown 

 colour, but were quite healthy, though not so active as the others, 

 and on casting their skins they were again white. 



The process of egg-laying was easily observed under a low 

 power. The eggs moved slowly down the vagina, and each egg 

 became slightly compressed as it reached the orifice, where it halted 



