Fifth report of the United States Entomological Commission, being a revised and enlarged edition of Bulletin no7, on insects injurious to forest and shade trees . trunks and branches of trees, and chieflyfrom near the base of the trunk. Each cocoon represents the death of one nearlyfull-grown caterpillar, since the latter harbors but one larva of the parasite.* A * In only one instance the cocoon of this parasite was found iuside of its host. 254 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. careful watch was kept to see how such a suspended cocoon was formed, but in a larvahad just
Fifth report of the United States Entomological Commission, being a revised and enlarged edition of Bulletin no7, on insects injurious to forest and shade trees . trunks and branches of trees, and chieflyfrom near the base of the trunk. Each cocoon represents the death of one nearlyfull-grown caterpillar, since the latter harbors but one larva of the parasite.* A * In only one instance the cocoon of this parasite was found iuside of its host. 254 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. careful watch was kept to see how such a suspended cocoon was formed, but in a larvahad just started to make a cocoon, but it was prevented from finishing itby a secondary parasite, and it died. Another larvahad already spun the rough out-side cocoon, but became detached and dropped out of the lower orifice, and commenceda new one. The larva, suspended by the mandibles, evidently spins at first loose, ir-regular, horizontal loops around its body, until a looso cradle is formed. The silksecreted for this purpose hardens very rapidly when exposed to the air. Whensecure inside this cradle it lets go its hold with the mandibles, and finishes the —Meteoriis hyphantrioe • a, female; 6, cocoon (enlarged). After Riley. inside cocoon in the usual manner. If the larva has dropped to the ground it stillmakes an outer loose cocoon, but the silken threads are thicker and much more ir-regular. In cocoons made during a high wind the threads that suspend them aremuch longer, reaching sometimes the length of 4 inches; the more normal lengthvaries from 1^ to 2 inches. To find out the length of time which this insect occupies in maturing inside thecocoon, forty-four freshly-made cocoons were put in a glass jar. With a remarkableregularity but ten days were consumed by the insect in changing from the larval tothe winged form. The winged Meteorus issues through a perfectly round hole at thelower end of the cocoon by gnawing o& and detaching a snugly-fitting cap. Thereare
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