14 Psyche [February 
spot. An examination of the soil in the fields revealed quantities 
of the worms below the surface at a distance of six inches to one 
foot. November the 7th and 8th, long after the grasshopper sea- 
son, the ground now cold was again broken and the nematodes 
were found coiled up at about the same distance below the surface. 
Undoubtedly they hibernate in these positions. 
During the highest mortality we made a series of dissections in 
order to determine the per cent. of parasitism. On a place called 
the Halladay Farm, we obtained the following astonishing high 
figures by the dissection of M. bivittatus. 
Sept. 8. 1009 © dissected and worms found in 59%. 
— 10. “80/29 i re ee Ge 
ee I AO) ra me = ee 62 
es 8. 400% ct Mi Ps Nee 
~ 105, 60sict) amor *, eS SRI 
2 OU: ig pe OE NS 
On a place called the Tarbox Farm, we dissected about equal 
numbers of M. bivittatus and M. atlanis and obtained the following: 
Sept. 8. 1002 @ dissected and worms found in 22%. 
ee 10. 75 Q Q ee ee ee 74 ee eae 4 
66 12. 60 Q Q ee “e ee ee “ec 950%. 
ee Se 909 ot ee ce «e ee ee 3%, 
“ec 10. 800% oe ee ee ee ee ee 5%. 
ee 12. 1000 oa “se ee ee ee “ee Or. 
In both series of dissections it will be noticed that the percentage 
of parasitism in females is much higher than in males. 
life-history of the worm is still so obscure we are at present unable 
to offer any explanation for this fact. 
How the grasshoppers become infected is unknown. 
nematodes are so large when they leave the grasshoppers in order 
to burrow into the soil, we are under the impression that grass- 
hoppers are the secondary hosts. 
animal might constitute the primary host. 
insect may furnish the clue to this interesting question. 
Since the 
Since the 
It is difficult to imagine what 
Perhaps some other 
Next summer we hope to extend our observations and attempt 
to gain a more complete insight into the life-history of this Mermis: 
parasite. 
Some parasites fluctuate so numerically from one season 
