JJo. 3. ] Silkworms in India. 147 



more consistence The ferment found in flaccid chrjsalides is associated with the 



debris of leaves, morsels of the trachea, and chlorophyl cells. These matters ordinarily 

 accompany the little ferment in the stomach of the chrysalis, hecause of the incom- 

 plete digestion of the leaf wheuever it is submitted to fermentation.' 



" No parasite indicative of flaccidity has been discovered other than this ferment, 

 which is not found in tlie adult insect ; and if the transformation into the moth is 

 permitted, all opportunity will be lost for detecting the disease. In pebrine, on the 

 contrary, the corpuscle is found in the moth as well as in the chrysalis. We might 

 therefore wait for a final examination of the moth to be made after oviposition. But, 

 in case disease is then found, it will be too late to stifle the cocoons, and the emergence 

 of the moths will have ruined them for certain commercial purposes. For this reason 

 it is important to detect the disease, if it exists, at as early a stage of the work as 

 possible. If the larvae have shown no external signs of the pebrine, it would be well 

 to microscopically examine a few of the last of the worms to spin. The corpuscles 

 will be found in these laggards, if anywhere. 



" Isolation and examination of the moths. — The development of the chrysalis 

 may be hastened or retarded by increasing or lowering the temperature. This fact is 

 taken advantage of to obtain a few adult insects which may be microscopically 

 examined before the whole lot become fully developed. Maillot {Lecons, page 250) 

 describes the method he adopts in France as follows : — 



" ' Three or four days before the cocoons are taken from the branches, we take, 

 here and there, from the early spinners as well as the late, several hundred cocoons ; 

 as, for example, 500 from a lot of 90 pounds. This sample should be placed in an oven 

 or warm room, where it will be kept day and night at a temperature of 100° to 110° 

 Fahrenheit and a high degree of humidity. In this way the formation of the moth 

 is hastened. As during this time the cocoons of the lot itself remain at a temperature 

 of from 75° to 90,° and often during the night at even lower temperatures, we shall 

 still have time to stifle them if the lot is discarded, or to string them into chains if, on 

 the contrary, it proves healthy. Every two days we take ten chrysalides from the 

 sample and examine them microscopically for corpuscles. If we find them in the first 

 eight or ten days, no matter in how small quantities, we can be sure that the pro- 

 portion of pebrinous moths will be considerable. When the chrysalides are mature, 

 which is easily seen by their eyes becoming black and the eggs harder to break 

 under the pestle, and also by some of them turning into moths, we proceed to 

 the definite examination. We crush one by one the mcths which have come 

 out and the chrysalides which remain and search for corpuscles ; the percentage 

 which is thus found will not differ materially from that which exists in the whole 

 lot.' 



" The examination of the chrysalides here mentioned may be made in the manner 

 already described when searching for the ferment of flaccidity and at the same time. 

 But if we are looking for tLe pebrine only, we need simply crush the whole chrysalides 

 in the manner hereafter described for the moth. Proceeding now with the stock of 

 which the purity has been ascertained by one or more of the different methods of 

 observation above described, 200 cocoons should be selected for each ounce of eggs 

 that it is desired to produce. In making this selection great care should be exercised 

 in taking only cocoons that are fine in texture and firmly made. This fineness is one 

 of the pre-requisites of a first class cocoon. The firmness of a cocoon, depending as 

 it does on the amount of silk which it contains, is an indication of the vigour of the 

 worm, and another item to be considered in selecting stock for reproduction. Rules 

 have been given for the determination of the sex of the inclosed insect, but this 



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