518 PSYCHOLOGICAL PHYSIOLOGY. 



beetles. The eggs of the bugs we find upon the leaves and stems of 

 plants, the juices of which the larvae imbibe ; the same in the plant 

 lice and Cicada, which select the same materials as food. The water 

 bugs live as larvae also in the water, and feed upon prey. We there 

 find their eggs, but generally placed in rows affixed to the stems and 

 leaves of plants growing beneath the water. 



294. 



But the maternal care is exhibited most strikingly in the order of 

 the Hymenoptera, and here presents itself in such a variety of forms 

 that we cannot refuse ourselves a detailed description of this attractive 

 subject. 



The Tenthredonodea, whose larvae, like the caterpillars of the Lepi- 

 doptera, feed upon fresh vegetable substances, cut with their saw-shaped 

 ovipositor the surfaces of leaves, and in these incisions deposit their 

 eggs. Here the larvae develope themselves, and subsequently feed 

 upon the same leaves. Thus their care for their progeny perfectly 

 corresponds with that of the majority of other insects. The Ichneu- 

 mons also are not distinguished by a greater anxiety from the rest ; they 

 deposit their eggs in other larvae, particularly in the caterpillars of the 

 Lepidoplera, and for this purpose they bore a hole with their pointed 

 ovipositor in the skin of the caterpillar, through which the egg passes 

 into its body. In the gall-flies the egg is also deposited in the paren- 

 chyma of the leaf, but steeped in a corrosive moisture, which occasions 

 a powerful influx of the juices to the wounded part. This thereby grows 

 gradually into a cellular body, the so called gall-nut, in the inside 

 of which the larva lives, feeding upon the juices ; it changes here into 

 the pupa, and also into the perfect insect, in which state it pierces 

 through the dwelling nature prepared for it through the care of the 

 mother, and then first sees the light of day. But this care is still more 

 striking in the fossorial wasps, all of which dig subterranean cavities, 

 whither they convey insects which they have caught and killed, and 

 in which they deposit an egg ; the body serves the young larva as 

 food, and the hole is a secure dwelling. We have before admired the 

 strength and patience which many species of this family apply to the 

 attainment of their object, and we then cited the large Ammophila 

 sabulosa as the best known and most striking instance. During the 

 summer we continually observe her incessantly employed in this labour ; 

 we may also admire her sagacity in the selection of a suitable soil, 



