>.s 



THE PRACTICAL ENTOMOLOGIST. 



able and t^oklerod together, instead of opening and 

 shutting as real jaws would necessarily do. I have 

 watched hundreds of these larva3 by the hour toge- 

 ther, and know that in the same larva the two prongs 

 always reTnain at the same angle with each other. 

 If they were really jaws, although we might not be 

 able to see them move, yet we should certainly find 

 them at different angles with each other at different 

 times. 



A few Bemarks on Silk-producing Lepidoptera. 



The following particulars relative to the breeding 

 in Japan of Samia ci/nthla Hubner, are gathered 

 from a Dutch translation of a Japanese work on the 

 subject, and may be interesting in view of the do- 

 mestication of this silk-producer in the United States 

 and its cultivation for commercial purposes. 



In the Japanese tongue this insect is called 

 " Yama-mayu," and is, in Japan, found wild on dif- 

 ferent species of oak trees, such as Querni^ sirocasi 

 Sieb., Q. serratus Thunb., and Q. dentatus Thunb. 

 It appears to live on fae ailanthus, A. glandidosa, 

 in China, and, so far as we are aware, has been 

 hitherto reared on this tree in the United States. 

 It would be interesting to try our native species of 

 oak as food-plants for the insect, since it appears 

 that both the size and quality of the cocoons are 

 affected by the different species of oak on which the 

 larvae are fed. It would appear that S. ci/nthia 

 feeds also upon other trees than the oak in Japan, 

 but that this is selected by silk-breeders on account 

 of its leafing early in the season ; the soft and deli- 

 cate leaves also cause it to be preferred. Like our 

 own " Attaci," Samia ci/nthia seems to be essen- 

 tially polyphagous. For the purpose, then, of using 

 the leaves for the rearing of the larvse, oak trees are 

 planted by the inhabitants around their farm-yards 

 and along the borders of the fields, etc. ; the culti- 

 vation of the silk-worm being very general by ag- 

 riculturists in Japan, though not as a speciality, 

 rather as a concomitant with general husbandry. 

 Three methods are employed in rearing the silk- 

 worms. By the first the worms are confined , though 

 open to the weather, and fed on branches, the lower 

 extremities of which are placed in water-jars. By 

 the second the branches are merely laid on the 

 ground, and by the third, the worms are reared on 

 trees growing in the open air. The first method is ne- 

 cessary for the proper preservation of the young larvae 

 immediately on their exclusion from the egg. The 

 young brood needs careful protection from the effects 

 of the wind. The selection of the eggs is a matter 

 of considerable importance. It is curious for us to 

 read that the venders of silk-worm eggs in Japan 



in many instances endeavor to palm off imitation or 

 manufactured eggs as genuine. The labor neces- 

 sary to successfully imitate so frail and small an 

 article as the egg of a moth, and that in quantities, 

 is a surprising illustration of the cheapness of ma- 

 nual labor, as well as of the ingenuity of the natives 

 of that country. In respect of color, the pale 

 mouse-grey eggs are the best; the dark grey are of 

 medium quality; on the other hand, the white eggs 

 are unproductive. 



In order to ascertain the quality of a lot of eggs, 

 a few should be opened and examined. If the egga 

 are thirty days old, a small pale blue worm will be 

 found developed in them. It is stated that the 

 eggs of the »S'. ci/nthia differ from those of other 

 silk-worms, in that the young larva can be detected, 

 developed, on opening them. In opening the eggs, 

 a razor or the point of a needle is used, while great 

 care is necessary in order not to crush the contents. 

 The best eggs are round, pale grey, and the heavier 

 they are, the more vitality will be found possessed 

 by the worms. A weight of 3,850 grammes of this 

 quality of eggs will produce 101,000 worms. 



The eggs of the middle sort are also round, but 

 smaller. On opening the thirty days' old egg, the 

 enclosed worm will be found but, unlike the worm 

 contained in the eggs of the best quality, it will re- 

 main comparatively passive if undisturbed, while 

 that contained in the first quality of eggs, under 

 similar conditions, is violent in its movements, indi- 

 cating greater vitality. The color of the worm of 

 the middle sort is dark blue, thus differing from 

 that of the first sort, than which it is also smaller. 

 The poorest sorts of silk-worm eggs are not quite 

 spherical, being depressed centrally. The larvaa 

 are very small on exclusion and weak. Such are 

 regarded as waste and thrown away. 



On or about the 22d of April a space is cleared, in 

 the open air, for the rearing of the silk-worms. 

 Ants and other insects destructive to the larvae, are 

 carefully removed and destroyed, and the allotted 

 space is surrounded by mats of native manufacture. 

 In this place a wooden bench or form is erected, 

 generally six feet in width, and long in proportion 

 to the quantity of worms desired to be reared. 

 Beneath this bench, which is open centrally, water- 

 jars are placed, which are provided with covers 

 having a circular aperture in the middle. Near 

 the bottom of the jar is an opening and a stopper, 

 to allow the water to be changed at will. The jars 

 are generally placed three feet apart. On the top 

 of the bench mats of very fine straw are laid, and 

 the eggs are spread out on these. Every evening 



