12 OLAV JOHAN-OLSEN. M.-N. KI. 
2. We know of no contagious bacterial disease of the chinch-bug. 
3. There are two parasitic, contagious, fungoid diseases that kill 
chinch-bugs, namely: Sporotrichum globuliferum (the »white fungus«), 
and Empusa aphidis (the »gray fungus«). 
Note, — Our experiments have to do mainly with the white fungus, as it is better 
understood and controlled than is the other. 
4. These two diseases show their greatest virulence where the 
ground is damp and shaded from the direct rays of the sun and the air 
is humid. 
5. We do not know to what extent the spores of these diseases are 
normally present in any given region. 
When they are present, whether naturally or artificially introduced, 
and the weather conditions are as given above, and the bugs are massed 
together, an outbreak of the disease will occur. The number of chinch- 
bugs killed in any field is approximately proportionate to the number of 
bugs in the field. 
Note, — It is true of the bugs as it is of ourselves, that the number of individuals 
carried away by a plague is dependent upon various conditions, such as those of weather, 
nourishment, density of population, etc. 
. 6. Sporotrichum can be artificially communicated to healthy 
chinch-bugs. 
(a) It attacks bugs of all ages, but the older the bug the more easily 
does it succumb. 
(b) Bugs of any age that have been weakened from any cause, or 
injured, fall more easy victims to the disease than do those individuals 
that are in perfect condition. 
(c) The adults of the second brood, which in the ordinary course of 
events winter over and lay the eggs for the brood of the succeeding 
spring, are much more successful in resisting the disease than are the 
adults of the first brood. 
(d) The fungus is not active in winter, and though it be present with 
the bugs in their winter quarters, they are not die of it, even though the 
winter be as mild and humid as was that of 1895 —06. 
Det fremgaar heraf, at heller ikke han har fundet nogen for det om- 
handlede insekt pathogén bakterie, men vel mugsoppe. 
Selv om der ikke forelaa andre heldige resultater end professor Snows, 
vilde dog disse været tilstrækkelig til ikke at opgive sagen herhjemme, 
især naar de sammenholdes med professor Giards resultater. 
