THE YOUNG NATURALIST. 



ORDERS OF INSECTS. 



(Continued from Page 39.) 



We told you last week of the four stages through 

 which all insects passed. _ The ovum, or egg ; the 

 larva, or caterpillar, Sec. ; the pupa, or chrysalis; 

 and the imago, or perfect insect. We resume our 

 subject by a few words about the eggs of insects. 



With some exceptions the eggs of insects do not 

 vary so much as do the other stages of their exist- 

 ence. They are generally round but sometimes 

 oval, square, and even more curiously shaped. 

 The eggs of the lace- winged flies are most extra- 

 ordinary looking things, having long stalks by 

 which they are attached, and much resembling the 

 knobbed antenna of a butterfly. Under the 

 microscope the eggs of many species are very 

 beautiful objects, their surfaces being marked and 

 reticulated, in endless diversity of pattern of most 

 exquisite design. They vary considerably in color, 

 many being white, drab, brown, while others are 

 light green, pink, &c. They generally change in 

 hue alter they are deposited, some directly after, 

 others just before the larva emerges. The eggs of 

 the swift moths are white at first, and turn black 

 in a very short time. 



The female deposits her eggs in various places, 

 according to the requirements of the young larvae, 

 sometimes singly, sometimes in clusters, arranged 

 with great regularity ; others are scattered loosely 

 about. Some are deposited on plants and trees ; 

 some on living, others on dead animals ; some 

 dropped on the surface of the ground, others on 

 water ; in wood, bark, refuse, or other things, but 

 of this you may be sure, they are placed in such 

 situation as will prove most advantageous for the 

 larvae when hatched. One of the first of the many 

 wonders of Natural History the writer learned was 

 in a School Lesson Book, which gave an account 

 of the Gadfly {(Estrus equi). The larva of this 

 fly must be nourished in the stomach of a horse. 

 ''How shall the parent," ask Kirby and Spence, 

 "a two-winged fly, convey them thither." It 

 would almost seem an impossibility, yet it is very 

 easily accomplished. The eggs are glued by the 

 female to the hairs of the horse, in such places as 

 it can easily reach with its tongue — generally the 

 knee or shoulder. So soon as they hatch the 

 slight irritation caused by the motion of the young 

 a rvse makes, the horse lick the place, they adhere 



to the tongue and pass into the stomach with the 

 saliva. The ova of insects whose larvae eat leaves 

 of plants arc often clustered on the underside of 

 such leaves, but in those cases where the leaves 

 fall off before the young larvae hatch the female 

 knows the eggs must not be placed upon them, and 

 you will see them round a twig, or in batches'upon 

 the stem. The female of the Common Vaporer 

 Moth (0- antiqua), is nearly wingless, and cannot 

 therefore travel far to find a suitable place for the 

 deposit of her eggs. The larva has greater power . 

 of locomotion, and when ready for changing it, 

 spins its cocoon in such a place that when the female, 

 emerges she has only to deposit her eggs on the 

 outside of it, and the young larvae have not many 

 inches to travel before they find suitable food. 

 The larvae of the Swifts {Hepialus), feed under- 

 ground, in roots, &c, and the eggs, which are 

 very minute, are scattered loosely about the ground. 

 They are not like many others, covered with a 

 gummy substance that makes them adhere to| 

 whatever they come in contact with, but are per-J 

 fectly dry, and are ejected with some force. Thusii 

 they have every facility for getting below the sur-i 

 face of the soil, penetrating into any crack oi 

 crevice, that the newly hatched larva may the 

 sooner find its food. There is a large tribe o 

 insects called ichneumons, whose eggs are depositei 

 in or upon the bodies of the larvae of other species; 

 Those which devour the growing larvae are inserte 

 within the body of their victim, by a curiousl 

 pointed ovipositor. Others are stuck outsidl) 

 ready to attack their prey, after it has spun itj 

 cocoon. The Puss Moth (Centra Vinula), is sull 

 ject to the attacks of an Ichneumon of this sorj 

 which deposits its eggs in the fold of the skin, 

 the retractile segments near the head, when tl 

 look like a string of beads. This larva is arr 

 with two curious instruments in the forks of 

 anal segments which it can dart out at anythii 

 annoying it, and by which it could drive off t 

 Ichneumons. Strange to say, it seems to lose t 

 power of using them after it has changed its sl< 

 for the last time, and they are thus of no servi 

 in preventing the eggs being deposited. This 

 the more remarkable because if the eggs we 

 attached before the last skin was cast they woi 

 be left with it, and when hatched would h 

 nothing to eat. Thus the unfortunate larva ser 

 its destroyer, by preventing the eggs being 

 posited when it would be to no purpose, 



