Fig. 77.—Water-tiger, the
larva of the predaceous
water-beetle, Dyticus sp.
(From specimen.)
Some of the stingless Hymenoptera are not parasites, but are gall-producers. The female with its piercing ovipositor lays an egg in the soft tissue of a leaf or stem, and after the larva hatches the gall rapidly forms. The larval insect lies in the plant-tissue, having for food the sap which comes to the rapidly growing gall. It pupates in the gall, and when adult eats its way out.
Fig. 78.—The plum curculio,
Conotrachelus nenuphar, a
beetle very injurious to plums.
(Photograph by M. V. Slingerland.)
The ants, bees, and wasps are called the stinging Hymenoptera, although the ants we have in North America have their sting so reduced as to be no longer usable. Among these Hymenoptera are the social or communal insects, viz., all the ants, the bumblebees and honey-bee, and the few social wasps, as the yellow-jacket and black hornet. There are many more species of non-social or solitary bees and wasps than social ones, and their habits and instincts are nearly as remarkable.
Fig. 79.—The currant-stem girdler, Janus integer, a Hymenopteron at work girdling a stem after having deposited an egg in the stem half an inch lower down. (Photograph by M. V. Slingerland.)