Calculation of the number of eggs per egg mass of the forest tent caterpillar, Malacosoma disstria Hiibner, is required in survey and population studies. Eggs are usually laid in cylindrical masses around twigs of trees. Hodson (1941) determined the number of eggs in egg masses of the forest tent caterpillar by counting the number of eggs around the circumference and multiplying by the number of rows. This technique is apparently reliable for comparative counts, but because the eggs are frequently laid in oblique rather than straight rows on the twig, counts of both length and circumference are subject to error. In addition, adjacent rows are often offset to form a honeycomb pattern which leads to inaccuracies in length and circumference counts. Because of these shortcomings, we developed a quicker and more accurate method not subject to the effects of oblique or honeycomb egg patterns.
Witter, J. A. and Kulman, H. M.
"Estimating the Number of Eggs per Egg Mass of the Forest Tent Caterpillar, Malacosoma Disstria (Lepidoptera: Lasiocampidae),"
The Great Lakes Entomologist: Vol. 2
, Article 3.
Available at: http://scholar.valpo.edu/tgle/vol2/iss2/3