150 Tlie Rocky Mountain Locust. 



those at greater depths were at that time unhatched. In 

 looser soil, they would doubtless have managed to push 

 somewhat farther. 



Experiment 30. — Ten egg-masses were placed just one inch be- 

 low the surface in the center of a box four inches in diameter. The 

 young began to appear January 30th, when it was noticed that 

 every one came up at the side of the box, between the earth and 

 the tin, where there was more or less shrinking of the former from 

 the latter. Upon pressing the earth more firmly around the border, 

 the issuing of the young ceased. Upon examining the eggs, March 

 7th, it was found that they had all hatched. A few of the young 

 were still alive, and endeavoring to escape ; the rest had died in the 

 effort. They had made no progress upward through the pressed 

 surface, but had pushed horizontally as the looser earth permitted. 



Experiment 31. — From ten egg- masses, placed two inches be- 

 neath the surface, the young commenced issuing from the sides, 

 as in the preceding Expt., January 31st. None issued directly 

 through the surface of the soil, and none issued after the border 

 was pressed more firmly to the tin. Subsequent examination 

 showed the soil penetrated in devious directions, but none of the 

 insects had reached higher than within three-quarters of an inch of 

 the surface. 



Experiment 32. — Ten egg-masses placed three inches below the 

 surface. The young began, January 31st, to issue from the sides, 

 as in Expts. 30, 31. Upon pressing the ground more firmly around 

 the borders, none afterwards issued, and subsequent examination 

 showed that the young had tunneled the earth in tortuous passages 

 toward the sides, and perished there; without reaching nearer than 

 within an inch of the surface in the middle of the box. 



Experiment 33. — Ten egg-masses placed six inches below the 

 surface. On February 1st, the young commenced to issue, as in the 

 preceding Expts., from the side, and continued to do so till the 

 4th, when the earth was pressed more closely to the tin. None 

 issued afterwards. Subsequent examination showed that some had 

 succeeded in working their way upward through the soil to within 

 two inches of the surface ; but most had reached the sides, and 

 there collected and perished between the tin and the soil. 



Other experiments made in glass tubes where the move- 

 ments of the insects could be watched, all produced results 



