Monograph of West American Melanellid Mollusks

Monograph of West American Melanellid Mollusks

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 edition. Excerpt: ...1 1.................... 1.......... 1 1 in 1916, the results being shown in Table No. VII. As will be seen from this table, two female adults lived thirty-nine days, but the average length of life was considerably less. While the cooler and more even temperature in the insectary may have been conducive to a more lengthy life, the abnormal confinement and artificial method of providing nourishment, may have been injurious. Consequently, it is possible that the average life recorded in Table No. VII may be exceeded under natural conditions. Daily dissections were made of female flies to determine the period required for the development of the eggs in the ovaries, and drawings prepared of the decisive stages, as shown in Plate I. The results of these studies would seem to indicate that a period of 26 days may elapse between the emergence of the fly and the final maturing of the egg. Field observations seem to justify the opinion that this period may be much shorter under orchard conditions. The flies used in these experiments were kept in a cool, shady situation, which doubtless had the effect of retarding the development of the eggs. In any case it is evident that several days must elapse between the emergence of the adult and the time the eggs are laid, and the comparatively long period during which the female must feed before depositing her eggs has an important practical bearing, since our control measures are based on this fact. O'Kane (78) records the complete development of the eggs in as short a period as four days after emerging, but from our observations it would seem very unlikely that under our conditions, development would take place in such a short time., Flies were found in copulo in the cages on the eighteenth day after...show more

Product details

  • Paperback | 66 pages
  • 189 x 246 x 4mm | 136g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236771060
  • 9781236771063