Image from page 541 of “American insects” (1905)
Title: American insects
Year: 1905 (1900s)
Authors: Kellogg, Vernon L. (Vernon Lyman), 1867-1937
Publisher: New York, H. Holt and Company
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries
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Text Appearing Before Image:
s, a parasite which lives in a sac in the abdomen of a Fulgond,Libumia lentulenta. (After Swazey; five times natural size.) scale-insects (Coccidae) and plant-lice (Aphididae), the eggs of locusts andother Orthoptera, and some Neuroptera in egg and larval stage, may beinfested; in fact the kinds of insects which may serve as hosts for the para-sitic Hymenoptera strongly outnumber the kinds that do not. While as a general rule each parasite confines its attacks to a single host-species, there are numerous exceptions; and on the other hand the hostitself may be attacked by more than one parasitic species; most of our familiarLepidoptera are parasitized by several different parasitic Hymenoptera. 48o Saw-flies, Gall-flies, Ichneumons, For example, the American tent-caterpillar has been found by Fiske (NewHampshire) to be attacked by twelve species. With regard to the number of parasitic individuals that may live at theexpense of a single host individual no generalization can be made; the
Text Appearing After Image:
Fig. 676.—Hymenopterous parasites of a social-wasp. Fig. 1, nest of Vespa sp., portionof two envelopes cut away (two-thirds natural size); fig. 5, an adult parasite,Sphecophagus (?) predator, female; fig. 6, male of same species; fig. 10, Melittobiasp., female. (After Zabriskie; natural size indicated by lines.) number varies, Howard says, from 1 to 3000. From a single caterpillarof the cabbage-moth, Plusia brassica, 2500 individuals of the parasite Copi-dosoma truncatellum have been bred. From large hosts are often bredlarge numbers of parasites, but with some parasitic species only one or a feweggs are ever laid on a single host, whether it be large or small. Small hostscannot, of course, provide food for many parasites and hence the number in Wasps, Bees, and Ants 481 their case is always limited. Still, from a single scale-insect hardly morethan J inch long a dozen and more tiny parasites have been bred. A question of interest is that regarding how many individuals of a singleho
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