. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 10 BULLETIISr 431, U. S. DEPAETMENT OF AGEICULTUKE. ceptible, white line. Sometimes there may be seen a narrow area along the median line of the ventral sm-face that is more nearly trans- parent than the remaining portion of the sm-face. This area may extend slightly into the anterior and posterior thirds. It is similar in appearance to the one on the dorsal side, but less distinct. A cross section of this third is slightly elliptical in outline. The middle third passes more or less gradually into the posterior third.
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 10 BULLETIISr 431, U. S. DEPAETMENT OF AGEICULTUKE. ceptible, white line. Sometimes there may be seen a narrow area along the median line of the ventral sm-face that is more nearly trans- parent than the remaining portion of the sm-face. This area may extend slightly into the anterior and posterior thirds. It is similar in appearance to the one on the dorsal side, but less distinct. A cross section of this third is slightly elliptical in outline. The middle third passes more or less gradually into the posterior third. The juncture on the ventral surface is indicated by a wide angle formed by the ventral surfaces of these two thirds. Posterior third.—In form the pos- terior third (figs. 6 and 4) is an im- perfect cone, the axis of which is directed somewhat upward from the horizontal. This third occupies the bottom portion of the cavity of the ceU. Its dorsal surface lies upon the bottom wall, with the extreme caudal end of the larva extending to the roof of the ceU (fig. 4). The third is marked off into segments by ridges and furrows similar to, but less regular than, those of the middle third. TISSUES OF A HEALTHY LARVA AT THE AGE AT WHICH IT DIES OF SACBROOD. Upon removing a larva in the late larval stage and puncturing its body wall lightly, a clear fluid almost water-like in appearance flows out. This fluid consists chiefly of larval blood. By heating it, or by treat- ing it with any one of a number of different reagents, a coagulum is formed in it. Upon rupturing the body wall , the tissues of the larva flow out- as a semiliquid mass. The more nearly sohd portion of the mass appears almost white. This portion is suspended in a thin liquid, chiefly blood of the larva. A microscopic examination shows that the cellular elements of the mass are chiefly fat ceUs. Many fat globules suspended in the liquid tend to give it a milky appearance. SYMPTOMS OF SACBROOD, The condition o
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