however, the color deepens to a sooty gray, commonly uniform, but 

 sonietimes first appearing about the center of the length of the 

 larva. Occasionally this deeper color appears a little before death, 

 but it is not then of equal depth over the whole surface. 



In the actions of the insect there is little to indicate any change 

 of state, except a gradually increasing sluggishness, slowness of 

 movement, and loss of appetite. These are later to appear than 

 the pale discoloration above mentioned, and even shortly before 

 death a larva may show considerable impatience if roughly handled. 

 When the disease is well developed, the caterpillar is very feeble, 

 and will remain motionless for a long time; or if it attempt to 

 crawl where some strength is needed, as horizontally on a vertical 

 surface, it may lose its hold with its jointed limbs and cling only 

 by its central prolegs, the fore and hinder parts hanging limp and 

 helpless at right angles to the remainder of the body. 



Most commonly an escape of fluid from the vent is among the 

 earlier symptoms of the affection, at first greenish or whitish, and 

 later a dirty gray, or even a chocolate brown. Earely this fluid 

 exudes also from the mouth. The amount of it is usually sufficient 

 to stain considerably the surfaces over which the larva crawls ; but 

 sometimes this symptom is wholly absent. Occasionally the intes- 

 tine is found empty after death, but almost invariably it is well 

 filled with food, much of which retains its native color, diges- 

 tion being, in fact, evidently suspended during the course of the 

 disease. I have found in only a single instance an appearance 

 of bubbles of gas in the alimentary canal. Usually the mass of the 

 alimentary contents seems to lie inert in the stomach, undergoing 

 neither digestion nor decay. 



The- color of the fluids of the healthy larva is a very pale trans- 

 parent green, the blood containing only lymphoid corpuscles in 

 greater or lesser number ; but if a proleg of a diseased specimen 

 be snipped off, and a cover glass be pressed against the cut sur- 

 face, the droplet exuding will be of almost milky whiteness, or, in 

 the latest stages of the disease, a dirty gray. Earely, where there 

 has been much escape of fluid from the vent, the juices of the 

 larva will be thick and scanty, so that it requires some pressure to 

 force out a very small quantity. If a minute droplet of the milky 

 fluid obtained by snipping off a proleg be examined under a high 

 power of the microscope, it will be found to contain innumerable 

 myriads of very minute spherules, varying in diameter, accordiDg 

 to the individual, from .5 // to 1 //.. Usually their average size does 

 not surpass .7 //. It is the infinite multitude of these which gives 

 to the fluids of the diseased caterpillar their milky look, and, like- 

 wise, unquestionably it is they which cause the ashy appearance of 

 the surface, the skin being thin and delicate, so that the color of 

 the fluid contents shows through. The diseased blood is so thick 

 with these minute corpuscles that little else can be ordinarily seen 

 in it. Sometimes, however, degenerated lymphoid corpuscles of the 

 blood will be noticed, recognizable by their size and spherical con- 

 tour, but differing from the normal corpuscles in their darker tint 

 and coarsely and irregularly granular structure. These darker, 

 granular corpuscles are always dead, no longer exhibiting amoeboid 

 movement, and have usually a spherical form. Not infrequently 



