THE YOUNG 



NATURA.LIST. 



293 



be called weapons of defence against man and 

 the larger animals ; they are rather weapons 

 oi offence, as many travellers have been pain- 

 fully made aware. 



Throughout their various stages of ex- 

 istence—viz., the egg, larva, pupa, and 

 imago forms — insects have various means of 

 defence. I shall give a few instances, con- 

 fining myself as much as possibh to the 

 order Lepidoptera, and more especially to 

 the insects that are found in this country. 



The Egg State. — The eggs of insects arc 

 as s rule, always laid in, on, or near sub- 

 stance upon which the future larvae may 

 feed, and their minuteness, must in a great 

 measure, protect them from birds and other 

 enemies, although such is not uniformly the 

 case. Small as they are, however, they can- 

 not always escape the eyes of certain small 

 ichneumons — Microgaster ovulornm in partic- 

 ular, the female of which introduces an egg 

 into them by means of her long ovipositor; 

 and when the parasitical larva emerges, it 

 feeds upon the other embryo larva. 



Insect eggs being so small, and apparently 

 so frail, it might be supposed that their 

 greatest enemy would be the weather, but 

 their nature is such that they enabled to 

 support with impunity a wonderful amount 

 of extreme heat and extreme cold. 



Spallanzani, in experimenting on the eggs 

 of the " silk moth " [Dombyx mori), and sub- 

 jecting them to various degrees of artifical 

 heat, found that they did not quite lose 

 their vitality till 144" Fahrenheit, whilst 

 they bore without injury an artificial cold of 

 23° below zero. 



The eggs are, moreover, generally pro- 

 tected from the inclemency of the weather 

 by the way they are laid, for the parent 



I insects, with an instinct which might easily 

 be confounded with foresij,'ht or reason, 

 generally deposits them close to the midrib, 

 or on the axil of the leaf, so that the danger 

 of their being destroyed is lessened. 

 The female of some species — the " gipsy " 



moth {Liparis dispar), for instance, whose 

 eggs have to bear the severe cold of winter, 

 plucks, by means of a kind of tweezers, with 

 which the end of her abdomen is provided, 

 the hair or down from the extremity of her 

 body, and wraps each egg separately in it, 

 and when all are laid, covers the mass with 

 the same down in such a manner that the 

 rain or frost cannot penetrate. Others, such 

 as the lacky moth [Bomhyx nenstria) and the 

 small egger [Eriogastcy lanestris), lay their 

 eggs round a twig of hawthorn or other 

 plants, and them cover them with a kind of 

 varnish, which effectually protects them 

 from wet and cold. 



Very often, also, eggs owe their security 

 to their colour resembling the substances 

 upon or in which they are laid ; and no 

 doubt the way in which the female insect 

 frequently disperses her eggs tends to pre- 

 vent the extermination of the species. 



The eggs of the " cockroaches" (Blattid^), 

 are laid in a very peculiar way, being en- 

 closed altogether, but in separate cells, in a 

 kind of case or capsule, in shape of a kidney, 

 consisting of a tough substance called chitine : 

 this case the female carries at the end of her 

 abdomen until all the eggs are laid, after 

 which it is deposited in some safe place. 



The lace-wing fly [Chrysopa reticulata), 

 whose larvae feed upon aphides, lays her 

 eggs on plants infested with these plant-lice 

 in a curious manner. She attaches a drop 

 of a gummy substance to the stem or branch 

 and drawing it out to the length of about an 

 inch, deposits an egg at the extremity. In 

 this way the egg is safe from attacks of the 

 larvaj of the lady-birds {Coccindlida), or of 

 the Syrphi. The foot-stalks of the eggs are 

 placed at intervals along the stems. 



The care and ingenuity which bees and 

 wasps evince for the safety of their future 

 progeny, from the attacks of parasites and 

 other enemies, as well as the solicitude with 

 which the ichneumons provide for the well- 

 being of their oflspring, is truly wonderful. 



