In this way you may search round tree after tree, wherever the soil is of such a character as to allow of the admittance and shelter of larvae. But the variability of your success will be quite beyond your comprehension. Sometimes you will sight a grand old oak with the most favourable anticipations, and consider yourself quite certain of a good find when you discover, on a nearer approach, the liberal coating of moss that clothes its trunk and the dry sandy soil at its foot; and yet the most careful search ends in nothing but disappointment. At other times you try your luck at tree after tree without ever seeing a single pupa or even a cast-off case, and then, when just on the point of despairing, you search round another that is apparently much less promising, and, to your great surprise and delight, a dozen or two are turned out in a few minutes. Such an occurrence as this is not at all uncommon, and cannot be satisfactorily explained, but we must take things as they come and make the best of them, remembering that pupa searching is one of the best of all entomological operations wherewith to test one's perseverance and patience. It may be mentioned, in conclusion, that the pupae of _Lepidoptera_ are never to be found far below the surface of the soil. Generally they exist, if buried at all, only an inch or two down, and very rarely at a greater depth than four inches. In our next chapter we shall learn how to rear the perfect insects from the earlier stages we have been considering. CHAPTER VIII _REARING LEPIDOPTERA_ _Management of Ova_ In the management of insects in all stages the strictest attention must always be paid to one general rule on which the success of the work almost entirely depends; and that is--keep every specimen as far as possible under the same conditions as those in which you find it in nature. Applying this principle to ova, we store them in airy and light places, protected from the direct rays of the sun, and avoid handling and rough treatment of any kind. It is also advisable in most cases to maintain a slight amount of dampness corresponding with that of the open air at the particular season of the year. They do not require much space, and it is certainly desirable not to give much, otherwise the newly hatched larvae, when their time arrives, will actively wander all round their premises in search of food, and give you no end of trouble in gathering them up.