Spiders, caterpillars and grasshoppers are, he said, stung in their chief nerve-centres, in consequence of which the victims are not killed outright, but rendered motionless and continue to live in this paralysed condition for several weeks, being thus available as food for the larvae when these are hatched.
We seem to be justified in assuming that there are many movements of stretching and posturing possible to caterpillars, and that some caterpillars had a congenital fortuitous tendency to one position, some to another, and, finally that among all the variety of habitual movements thus exhibited one has been selected and perpetuated because it coincided with the necessary conditions of safety, since it happened to give the caterpillar an increased resemblance to a twig.
The latter is the more serious, as in addition to the actual damage done by the beetle the holes afford entrance to fungus spores, &c. Under the name " horn worms " are included the larvae or caterpillars of species of Protoparce.
Other caterpillars, "budworms" (Heliothis, spp.), attack the buds or burrow into the seed-pods.
Seedling plants of tobacco, like many other crops, are liable to attack by " cut worms," the caterpillars of species of Peridromia and Agrotis.
The Tenthredinidae, or true saw-flies, are distinguished by two spines on each fore-shin, while the larvae are usually caterpillars, with three pairs of thoracic legs, and from six to eight pairs of abdominal prolegs, the latter not possessing the hooks found on the pro-legs of lepidopterous caterpillars.
Pelopoeus hunts spiders, while Ammophila catches caterpillars for the benefit of her young.
The gizzard of various birds which are addicted to eating hairy caterpillars, e.g.
Cuculus canorus and trogons, is often lined with the broken-off hairs of these caterpillars, which, penetrating the cuticle, assume a regular spiral arrangement, due to the rotatory motion of the muscles of the gizzard.
Besides the aphids, other insects, such as scale insects (Coccidae), caterpillars of blue butterflies (Lycaenidae), and numerous beetles, furnish the ants with nutrient secretions.
The caterpillars of the leopard moth (Zeuzera pyrina) and of the goat moth (Cossus ligniperda) sometimes bore their way into the trunks and destroy the sap channels.
The early stages if the entrance of the caterpillars has been detected, a wire should be pushed into the hole.
The series of paired spiracles on most of the trunk-segments is well displayed, as a rule, in terrestrial larvae - caterpillars and the grubs of most beetles, for example.
Occasionally vast armies of locusts or caterpillars advance over large tracts of country, devouring all vegetation in their line of march.
Now it is clear that preceding generations of caterpillars cannot have acquired this habit of posturing by experience.
Tobacco dust will dislodge most of the numerous kinds of slugs, caterpillars or worms that make their appearance on the young shoots of vines or trees.
This is effected not so much by their numbers and their powers of con - sumption, as amongst caterpillars, but by their habits of attack - ing the essential parts of a plant, and causing by their injuries the death of the plant affected.
Erosions 01 leaves and herbaceous parts by caterpillars, slugs, earwmgs and sc forth.
General attacks of leaf-diseases invariably lead to starvation and necrosis of twigs, and similarly with the ravages of caterpillars and other insects.
The larvae of these are usually spoken of as " false caterpillars," on account of their resemblance to the larvae of a moth.
Some of these glands may be modified for special purposes - as silk-producing glands in caterpillars or as poisonglands in blood-sucking flies and bugs.
The pseudopods that exist on the abdomen of numerous caterpillars may possibly arise from the embryonic pseudopods, but this also is far from being established.
Larvae caterpillars with thoracic legs and abdominal prolegs.
The caterpillars (" cut worms ") of various species of Agrotis and other moths occur in all parts of the world and attack young cotton.
Such cases are the habits of " shamming dead " and the combined posturing and colour peculiarities of certain caterpillars (Lepidopterous larvae) which cause them to resemble dead twigs or similar surrounding objects.
The growth of the worms during their larval stage is thus stated by Count Dandolo: - When the caterpillars are mature and ready to undergo their transformation into the pupa condition, they cease eating for some time and then begin to ascend the brushwood branches or echelletes provided for them, in which they set about the spinning of their cocoons.
Still more rarely mimicry exists between totally unrelated species like caterpillars and snakes or spiders and snails.
Moreover, young birds that had been taught by experience that these caterpillars are uneatable also left wasps untouched.
Another instance of mimicry affecting the larval form is supplied by the moth Endromis versicolor, the caterpillars of which resemble the inedible larvae of saw-flies.
These wasps, moreover, also provision their nurseries with caterpillars, grasshoppers and other insects.
Pick caterpillars from gooseberries and wall trees on their first appearance.