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An egg-containing capsule, such as an ootheca or a Graafian follicle.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Zoology) a capsule or sac, such as an ootheca, in which egg cells are produced
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈoʊ vəˌsæk)

a sac or capsule containing an ovum or ova.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
References in periodicals archive ?
However, the ovisacs of scales could prevent heat and moisture exchanges and maintain a relatively stable microenvironment inside (Gullan & Kosztarab 1997); thus, air temperature may not represent the best predictor for temperature inside the ovisac.
Sars (1911) observed the swimming behavior and the presence of an "ovisac" in the shallow-water hyperbenthic Misophria pallida Boeck, 1864.
They are covered by a thick layer of white wax with series of tufts and filaments, as follows: (i) a long caudal tuft, 6.6-13.5 mm long (Figure 1a, b), (ii) a cephalic tuft (always shorter than the caudal tuft) (Figure 1b), (iii) lateral filaments, with those closest to the caudal tuft longer than the remaining filaments (Figure 1c) and (iv) an ovisac 4.1-8.5 mm long (Figure 1d).
The crawlers disperse from the ovisac by way of walking, wind, or ants.
After the emergence of first instar crawlers from the ovisac, twenty five first instar nymphs were isolated and brushed by camel hair brush over the twig of each experiment unit through the hole made in the 2nd inverted cup.
(2011a, b) studied morphological characteristics (ovisac morphology in females and the frontal knob morphology and ornamentation (number of spines and mechanoreceptors), as well as the basal part of the penis, in males) of some Tunisian Artemia populations.
Various studies have examined fecundity in spiders (Cooke 1965; Levy 1970; Muniappan & Chada 1970) and, according to Downes (1985), the estimates of fecundity should include the number of emerged spiderlings and all of the individuals in different stages of development which belong to the same ovisac, including undeveloped eggs.
These species can be separated in life mainly by the length and shape of the ovisac, which is longer and with parallel edges in P.
salvator was an unpaired structure (see Figures 1 A, D), but it was noteworthy that oocytes at different stages of development appeared to be grouped, independently of each other, into a structure that was similar to an ovisac (see Figures 1 A, B, E).
Its development rate reduced to half in older mealybugs parasitized during the ovisac formation period as compared to those in pre-oviposition stage.