One difficulty of the ova collector lies in the fact that many insects lay on the upper branches of large trees. Of course a search for these is out of the question; but in places where the trees have been cut down a few years previously, and where a consequent undergrowth has developed, there are considerable chances of success with these species. Young saplings of trees often yield well, especially in places where tall trees of the same species are absent. It may be mentioned, too, that some moths ([page 294]) actually lay their eggs beneath the surface of water, depositing them on the under surfaces of floating pond weeds; and others ([page 298]) even enter the nests of wasps and bees for the same purpose. It is clear, then, from these few remarks, that the work of an ambitious collector of insects' eggs is by no means a monotonous task; for his employment takes him into the meadows and woods, leads him to the banks of ponds, and even compels him to tear down banks and hedges for the nests of Hymenoptera at the risk of a sting or two.
One of the most productive sources of eggs is undoubtedly the possession of captured females. When you are out netting butterflies you often see a female that is evidently engaged in her matronly duties. Instead of seeking food from the various flowers in her path, she pays attention only to the foliage, looking out a suitable leaf on which to deposit her eggs. Should you meet with an insect thus engaged which you would like to rear at home, or of which you would like to know the egg, secure it in a perforated pill box with a leaf of the proper plant; and it will often supply you with abundance of eggs for your purpose, in many cases depositing them in the box before you arrive home. The eggs of numerous species of moths are also to be easily obtained from captured females.
Some insects do not seem inclined to deposit their eggs in captivity as freely as when at large, and in order to induce them to do so we must, as far as possible, put them in their natural conditions. Let them have plenty of room, and supply them with fresh twigs of their food plants, kept green by standing them in vessels of water. It is also advisable, supposing you are not well acquainted with the dispositions of the species you have, to keep a portion of the box well shaded from direct sunlight, and allow another part to be
as bright as possible; for some species will not lay in a bright light, while others will not do so without it.
Again, while some deposit their eggs within a few hours of quitting the pupa case, others do not lay for several days. With regard to the latter, it is frequently necessary to feed them while in captivity, by placing in the box a piece of rag or sponge that has been dipped in honey or syrup.
Each batch of ova should be carefully examined with a view to knowing them by sight on a future occasion. A sketch should be made in your note book, showing every detail that you can make out with the aid of a good lens. Then observations concerning the season, colour of the eggs, the situation in which deposited, arrangement, and any other useful particulars, should be entered.
In the next chapter some hints will be given concerning the management of ova and the rearing of the larvæ from the time of hatching.
Collecting Larvæ
This occupation is generally far more productive to the entomologist than searching for ova. The latter are very small, usually well concealed, and to be detected only by a careful scrutinising use of the eyes; but the superior size of the larvæ, the frequent bright colouring, and the fact that they are easily beaten from their hold, render the searchings of their hunters comparatively easy and fruitful.
Before setting out on a larva-hunting expedition, there are a few requisites to prepare. These include not only the implements for your work in the field, but also the cages in which you intend to rear your little captives. The latter are described a little later on under the head 'Rearing Lepidoptera,' and the former we will now briefly summarise.