Book VII. 



NOXIOUS INSECTS. 



1073 



light of fliosnn, being produncHl after sunset, during the short nights of summor, and dying long before 

 the dawn. All iheir enjoyments, therefore, excepting coition, are confined to their larva state. The E. 

 vulgata (fig. 15'J f>) Is the largest British species. 



6899. The spring fly (Phrj/gnnea), in the caterpillar state, lives in the water, and is covered with a silken 

 tube. The caterpillars or larva have a very singular aspect ; for, by means of a gluten, they attach to the 

 tubes in which they are enclosed small pieces of wood, sand, gravel, leaves of plants, and not unfrequently 

 live on testaceous animals, all of which they drag along with them. They are very commonly found on 

 the leaves of the water-cress; and, as they are often entirely covered with them, they have the appear- 

 ance of animal plants. They are in great request among fishermen, by whom they are distinguished by 

 the name of stone or cod-bait. The fly, or })erfect insect, frequents running water, in which the females 

 deposit their eggs. P. rhombica (fig. 759 c) is common. 



SuBSECT. 6. Of Hymenopterous Insects. 



6900. The order hymenoptera, or four-winged insects with stin/rs, includes the gall 

 insect, wasp, Lee, ant, &c. At the extremity of the abdomen, the female.s of several of tlie 

 genera have an aculeus or sting, that lies concealed within the abdomen, which is used as 

 a weapon, and instils into the wound an acrid poison : those vvhich want the sting are 

 furnished with an oviduct that is often serrated, and with which the eggs are deposited, 

 either in the bodies of the caterpillars of other insects, or in wood. From these eggs the 

 larvfE are produced, which in some have no feet, in others more than sixteen. They 

 change to pupce iiicompletfe, which are enclosed in cases. Some of the insects of this 

 order live in societies, others are solitary. 



6901. The gall-fly [Cynips) pierces the leaves, &c. of plants with its sting, and deposits it eggs in the 

 wound ; the extravasated juices rise round it, and form a gall {fig. 760 a) which becomes hard ; and in this 

 the larva (6) lives and feeds, and changes to a pupa (c c), and afterwards to the imago or pcrCect insect 

 (rf). The C. quercus folii {fig. 760 d), and C. glechomatis, or ground-ivy gall-fly, are very common. 



160 



6902 . The saw-fly {Tenthredo), in the larva state 

 {fig. 760 ri, bears a strong resemblance to some of 

 the caterpillars of the lepidopterous insects ; but is 

 distinguishable by the number of the feet, which 

 are never fewer than sixteen, exclusive of the 

 thoracic pairs ; the larva feed on the leaves of 

 plants, and the pupa is enclosed in a strong gummy 

 case (/), retiring in the autumn, and the perfect 

 fly {g) emerges early in the ensuing spring. The 

 serrated sting is used by the female in the manner 

 of a saw, to make incisions in the twigs, or stems 

 of plants, where it deposits its eggs. T. rosa 

 {fig. 760 e, fyg), is a common species. The T. gros- 

 sulariae {h) is also frequent in gardens ; both are 

 very troublesome species of this genus. 



6903. The ichneumon is a very numerous genus, 

 there being upwards of 800 British species. The .^ 

 eggs, in most kinds, are deposited in the bodies of ^ 

 caterpillars or pupa, which are there hatched : 

 the larvffi have no feet ; they are soft and cylin- 

 drical, and feed on the substance of the caterpillar ; 

 this last continues to feed and even to undergo its 

 change into a chrysalis, but never turns to a per- 

 feet insect : when the larvas of the ichneumon 

 are full grown they issue forth, spin themselves 



a silky web, and change into a pupa incompleta, and in a few days the fly appears. The I. manifestator 

 {fig. 760 i) is common in woods. 



69(J4. The bee {Apis), wasp {Vespa), and ant (Fo>7/crt), are well known. All the species of ant are of 

 three sorts, male, female, and neuter. The neuters alone labor; they form the ant-hill, bring in the 

 provisions, feed the young, bring them to the air during the day, carry them back at nigiit, defend them 

 against attacks, &c. The females are said to be retained merely for laying eggs, and as soon as that is 

 accomplished they are unmercifully discarded. The males and females perish with the first cold ; the 

 neuters lie torpid in their nest, and thus nature compensates them by duration, what it denies them in 

 intensity of enjoyment. 



SuBSECT. 7. Of DijHerous Insects. 



6905. The diptera, or two-winged insects, have two wings, and behind or below them 



two globular bodies, supported on slender pendicles, called hnlteres or poisers. 



5 Z 



At the 



