﻿OF THE STATE ENTOMOLOGIST. 105 



Experiment 30. — Ten egg-masses were placed just one inch below the surface in the 

 centre of a box 4 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 

 etlort. They haa made no progress upward through the pressed surftice, but had 

 pushed horizontally as the looser earth permitted. 



Experiment 31.— From 10 egg-masses placed 2 inches beneath the surface the young" 

 commenced issuing frum the sides as in the preceding Exp., Jan. 31st. None issued 

 directly through the surface of the soil, and none issued after the border was pressed 

 more tirml}- to the tin. Subsequent examination showed the soil penetrated in devi- 

 ous directions, but none of the insects had reached higher than within \ inch of the 

 surface. 



Experiment S2. — Ten egg-masses placed 3 inches below the surface. The yourhg 

 began, Jan. 31st, to issue from the sides as in Expts. 30, 31. Upon pressing the ground 

 more firmly around the borders, none afterward 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 6 inches below the surface. On Feb. 1st 

 the young commenced to issue, as in the preceding Expts., from the side, and con- 

 tinued to do so till the 4th, when the earth was pressed more closely to the tin. None 

 issued afterward. Subsequent examination showed that some had succeeded in work- 

 ing 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 movements of 

 the insects could be watched, all produced similar results to those 

 above given, and all point to the conclusion that where the newly 

 hatched insect has not the natural channel of exit (described on p. 88) 

 which was prepared by the mother, it must inevitably perish if the 

 soil be moderately compact, unless cracks, fissures, or other channels 

 reaching to the surface, are at hand. 



From the above four series of experiments, I would draw the fol- 

 lowing deductions, which have important practical bearing: 



J^irst — Frost has no injurious efiect on the eggs ; its influence is 

 beneficial rather, in weakening the outer shell. 



Second— Ahernsite]y freezing and thawing is far less injurious to 

 them than we have hitherto supposed, and tends to their destruction, 

 if at all, indirectly, by exposing them to the free air. 



Third — The breaking open of the egg-masses, and exposure of 

 the eggs to the atmosphere, is the most efi'ectual way of destroying 

 them. Hence, the importance of harrowing in the Fall is obvious. 



Boiirtli — Moisture has altogether less eifect on the vitality of the 

 eggs than has heretofore been supposed, and will be of little use as a 



