MEGASTIGMUS SPERMOTROPHUS, WACHTL. 59 
Lire-HIsTtoRY AND HABITS OF CHALCIDIDAE. 
The great majority of the Chalcididae are parasitic on insects. 
Eggs may be parasitised, as in some of the cockroaches, or 
pupz may be infested, but far the commonest stage for infesta- 
tion is the larva. The larval host may be a gall-maker, or a 
guest in a gall, or a feeder in a mine or burrow in the plant, or 
an external feeder. 
The female Chalcids lay their eggs on or in the host. In the 
majority of cases the larve, on hatching, feed internally. If the 
larval host feed enclosed on plant-tissue, the Chalcid parasite 
may feed externally on it. There are a few cases known where 
the parasitic Chalcid larva feeds externally on an external 
feeding host. When full grown, the parasitic larva passes into 
the pupal stage without making a cocoon. 
The range of insect host parasitised by Chalcid larve is a 
very wide one. Scarcely any insect Order escapes. Dr L. O. 
Howard points out! that the non-parasitised insects, the May- 
flies and the Dragon-flies, and Thrips and 7hysanura, are either 
aquatic forms in their early stages, or very tiny land forms. 
Following Howard, the commonest orders parasitised are the 
Lepidoptera, the Hymenoptera, and the Hemiptera-Homoptera. 
The caterpillars of Lepédoptera are very commonly parasitised, 
those of the Micro-Lepidoptera more often than of the Macro- 
Lepidoptera. Among Hymenoptera, the bee section, the gall-flies 
and the saw-flies all suffer, while Chalcid parasites are also 
found infesting Ichneumonids, Braconids, and even other 
Chalcids. 
Of the Hemiptera-Homoptera, the Scale insects, Aphids and 
Psyllide are much infested. 
Of the remaining insect Orders, a number of beetle-families 
provide Chalcid hosts. Of the Diptera we find Chalcid parasites 
levying toll on the gall-gnats (Cecidomyide), the crane-flies, and 
the Muscide. Orthoptera also suffer, and among the WVeuroptera 
the ant-lions and the predaceous lace-wing flies. 
While it is not possible to say absolutely that each Chalcid 
section confines its parasitism to a special family of insects, yet 
one can say that certain of the Chalcid genera affect, and even 
limit their parasitism to, specially chosen families. 
1** Biology of the Chalcididae, 1901,” Proceedings United States Nat. Muts., 
vol. xiv. By Dr L. O. Howard. 
