REPORT OP THE ENTOMOLOGIST. 223 



out witli ii pair of tweezers. The restricted part of the di<::estive tube, 

 wliifh unites the stomach with the urinal sack, ?<, sliould then be cut. 

 Tht* anterior part of the digestive tuhe now alone holds the stomach in 

 place, and this easily gives way. Lay the small ball thus withdrawn on 

 a glass slide and scratch away the very soft fatty envelope which covers 

 tlic interior. Of this interior substance take a piece as big as the head 

 of a pin. wash it with a drop of distilled water, and, placing it npou a 

 slide with a cover-glass over it, examine it Avitli a microscope magnify- 

 ing about four hundred diameters. With a little experience this work 

 may be done very rapidly. It would be well to take out at the same 

 time the stomachs of, say, twenty chrysalides, and lay them on as many 

 glass slides. * * * 



"The lirst few days after the formation of the chrysalis the conlents 

 of the stomach are generally very liquid, which makes their extniction 

 inconvenient. It is better to make these observations seven or eight 

 days after the spinning begins, when the matter will be found to have 

 more consistence. * ♦ » Plate III, Fig. 1, shows the api)earance 

 of the ferment found in liaccid chrysalides under a magnifying power 

 of four hundred diamett-rs. It is associated with the debris of leaves, 

 morsels of the trachea, and chloropLyl cells. These matters ordinal ily 

 accompany the little ferment in the stomach of the chrysalis becaus«' o!' 

 the incomplete digestion of the leaf whenever it is submitted to Iwmen- 

 tation." 



PEBRtNE. 



Sympioms. — "The disease, iichrine, sliows itself ontwardl;^' by the 

 dwindling away of the worms and their inequality of size; eatmg little, 

 they do not grow as large as when in their normal state. At tlie end 

 of a few days black spots frequently make their appearance on the skin, 

 resembling punctures or burns.''* Plate II, Fig. 4, '' rei)resents, twice 

 the natural size, the anterior part of the body of sick worms covered with 

 the. spots of which I treat. In one of the worms, «, they are just becom- 

 ing visible, and the eye should be aided by a magnifying glass to render 

 them distinct ; the other, h, shows them iarther advanced, easily recog- 

 nizable with the naked eye, if the worm be examined with, a little at- 

 tention. Finally, Fig. 3 shows one ring spotted witli the pebrinc^ luag- 

 nified to six diameters. For this cut was chosen a worm bearing two 

 kinds of marks, one with clear cut edges, the others surrounded witis a 

 halo. The lirst are wounds, the others tlic true spots belonging to the 

 disease and serving as an indication of its existence, if not always, at 

 least under many circumstances. The halos in question have generally 

 a yellowish tint f they must be observed through a magnifying glass to 

 be well seen."t "The anal horn, the jnolegs, the soft parts between the 

 rings are especially subject to these black spots. In the interior of the 

 l>ody microscopic observation reveals the presence of innumeraV)le cor- 

 puscles of an ovoid shape (Plate 111, Fig. 2), filling the cells of the walls 

 of the stomach, those of the silk glands, the muscles, the fatty tissue, 

 the skin, the nerves, in a word, all the portions of the body. There ;irc 

 often so many of them that the cells of the silk glands become swollen 

 and white and appear to the naked eye to be sprinkled over with chalky 

 spots ; the silky liquid always remains exempt from this parasite, but 

 it is much less abundant than when the worm is in a healthy state." | 



* Maillot. Lemons snrle Vers a soie du Miirier, tf-c, p. 96. 



t Pasteur, j£tude8, <J-c., p. 15. 



t Maillot, Lemons, ^-c, pp. 96, 97. 



