46 STATE UNIVERSITY EXPERIMENTAL STATION. 



EXPLANATION OP FIGURES. 



Plate I, figure 1, culture of Sporotrichum growing on squash; figure 2, 

 culture on Irish potato. 



Plate II, figures 1 and 9, Sporotrichum growing on the surface of de- 

 coctions of squash; figure 2, culture on rabbit dung; figure 3, on horse 

 dung ; figure 4, on squash ; figures 5 and 8, Irish potato. In tubes 5 and 

 8, the transfer was made from a growth of Sporotrichum found on an insect 

 among leaves in a wood near a cultivated field, January 10, 1895. Figure 

 (5, culture of Sporotrichum on turnip; figure 7, on oniou. 



Plate III, figure 1, shows the chinch bug in various stages of its life, 

 magnified. At (a) is the red larval stage. At (b) the black pupal stage 

 ready to shed its skin and appear with wings. At (c), the pupal bug in the 

 act of shedding its skin ; the skin bursts open in a line along the back and 

 through this crack the adult bug emerges with some effort. At (e) is shown 

 the empty skin. The crack along the back often closes completely, and the 

 skin is easily mistaken for a dead bug by anyone unacquainted with it ; the 

 skins are exceedingly light, however, and may be blown about by the slight- 

 est breath. At (d) is shown the adult bug just after emerging from the 

 pupal skin. At this time the bug is light pink in color and is often mis- 

 taken for a sick bug because of its light color. The adult soon takes on a 

 dark color and appears as seen at (/). 



The above stages are normal to the chinch bug, and none of the appear- 

 ances described are to be taken as evidences of disease. When the bugs 

 are about to shed their skins they run about uneasily and gather into 

 bunches in sheltered places. This habit affords a good opportunity for the 

 spread of the disease, but it is not itself to be taken as evidence that the 

 disease is working. The only sure evidence to the farmer that the disease 

 is working is the presence in his field, under clods, fallen cover, etc., of 

 dead chinch bugs covered with a growth of the white fungus, such as is 

 seen on the bugs sent out by the experiment station. 



Plate III, figure 2, is a photo-micrograph of a portion of a cross section 

 of a fungus-covered chinch bug. The clusters of spores of the Sporotrichum 

 may be seen on the long stalks issuing from the body of the insect. Within, 

 the body of the bug is filled with the intertwined filaments of the fungus. 



Plate IV, figure 1, is a photo-micrograph of a portion of a cross section 

 of a diseased bug. The filaments in the open space in the upper right-hand 

 portion of the figure, which corresponds to the center of the body, like 

 those outside of the insect, are much finer than those in the other parts of 

 the body. Figure 2 shows the larger filaments much more highly magni- 

 fied. 



