IXTRODUCTIOX. xi 



known as mimicn-, or protective resemblance, in which one insect resembles another with which it 

 has no real affinity, but which enjoys some special immunity from the attacks of birds or other 

 enemies, is always seen in the greatest perfection in the female, to which sex it is indeed often 

 confined. The sexual differences presented by the antennns, frenulum, and front legs, &c., have 

 been already noticed. Specimens are occasionally met with in which the characters of the two 

 sexes are combined in one individual. In some cases the opposite sides of the body present all 

 the characteristics of the two sexes, the wings, legs, antennae, &c., being male on one side, and 

 female on the other. These are called hermaphrodites, or gynandromorphous specimens. In 

 other cases, difterent oarts of the insect combine the colour or structure of the sexes to a greater 

 or less extent. Any specimen combining the characters of both sexes in any degree is a rarity 

 which must on no account be passed over ; and if, by rare chance, the captor happens to reside 

 in the same neighbourhood as an entomologist who studies the anatomy of insects, the specimen 

 should be submitted to his examination immediately, while still quite fresh. I may add that 

 perfect hermaphrodites are confined to those animals in which the sexes are not separated ; and 

 that when the sexes are combined in an individual of a species in which they are normally 

 separated, such individuals are always imperfect hermaphrodites, however completely the sexes 

 may appear to be combined, and are generally incapable of fulfilling the functions of either sex. 



EGGS. 



The eggs of Lcpidoptci-a are small bodies, covered with a hard shell, and filled with fluid, 

 containing the germ of the larva, and the nourishment required for its preliminary development. 

 They are very interesting objects for examination with a microscope of low power, for their shapes 

 are very varied, and are often remarkable. Some are globular, others egg-shaped, bowl-shaped, 

 cylindrical, barrel-shaped, cheese-shaped, turban-shaped, &c. ; and they are often truncated orhollowed 

 at the ends. Their surface is either flat, or covered with impressed or raised points, and there are 

 often furrows or deeper stripes running along the sides from the middle of the upper end, like the 

 meridian lines on a globe ; the intermediate spaces between these stripes are generally rounded, 

 and raised, with fine transverse stripes, and the intermediate spaces between these are often again 

 still more finely ribbed. The colours of the eggs are also very various : they may be brown, blue, 

 green, red, or yellow, but are most frequently greenish or greenish-white, and are often spotted, 

 striped, or marked with net-like or other patterns. The eggs of nearly-allied species have 

 generally a particular definite shape, especially in sharply-characterised groups. 



The eggs are laid by the female insects in places where the future larvae can easily find their 

 food, and most frequently on the plant on which they are to feed. They are either laid singly or 

 in numbers, and sometimes the whole mass is laid at once. They sometimes form an irregular 

 heap, often covered with hair or wool taken from the body of the mother, and are sometimes 

 arranged in several rings, set close together, around a twig, or are attached to a flat surface, 

 generally that of a leaf. After a few days, fertilised eggs generally become slightly depressed 

 and change colour, and unfertile eggs shrivel up. Unfertilised eggs produce no larvae, except 

 among some genera of small moths, and, in very rare cases, among large moths. Among silk- 

 worms, for instance, the development of unfertilised eggs has frequently been observed. This 

 phenomenon is called Parthenogenesis, from ■7rapOevo<;, a virgin, and yev£cn<;, birth. 



The period required for the formation of the germ in the egg pre\-ious to its hatching varies 

 according to the time when the egg is laid, and the season when the larva will find food. In 

 summer the development is more rapid, and in autumn and winter it takes place more slowly. 



