61 
the area where disease had been distributed, and two days later exam- 
ples were found a quarter of a mile from the starting point of the dis- 
ease. Immediately after this, however, another halt, both in the in- 
tensity of attack and rapidity with which it spread, due either to the dry 
weather, or to the fact that the bugs had now all reached the adult 
stage, and had become diffused over the country, no longer congregat- 
ing together. From either one or the other, or both of these causes, I 
lost track of the Entomophthora and was not able to again find it in the 
fields. It seems proper to state here that Chinch Bugs were not at any 
time excessively abundant. The greatest numbers were in the exact 
localities where the disease was first distributed, the congregating at 
these places being brought about by the close proximity toa large num- 
ber of small experimental plats of wheat, and when this was harvested 
the*bugs. collected en masse on the corn and young wheat. In connec- 
tion with these facts, it is also interesting to note that from July 15 to 
August 51 there were ten days on which rain fell. The dates of these 
rains and the amount of pees is oven below: 
| Precipi- | ‘ | Precipi- 
Date. Teoria Date. tation. 
Inches. | Inches. 
Jie Uf steecboespeededcccanecenusbqapeac ol) | OIIN) BY) ere coroncsapnatnacednnoneosocebe .78 
= chose SS ooes BEaas Sone cossesoe0> 1, 25 sQbeciSsa St 6onessaosaqreccssoescs 50 
UN SoSS oe OAS REE CSCO DSO bSEOoeacSooS BA eel Oe Ol versie wie tec epeteerersiat eee reece 3.36 
DORE ae pr eteem asics Selanne ers - 04 | 1B Back Sabopaadone erate opopnesneser 15 
7D. ooosocnocisuobeose) sasegsensceses 12 IEWISEE cdiGoobaccosscadacr Baokeoade 02 
With a view of learning whether o or ‘not there v was any difference as 
regards susceptibility to the attack of Hntomophthora, between bugs in 
different stages of development, a series of experiments was begun, as 
follows: 
Young plants of Setaria glauca were transplanted to a box, and upon 
each plant was placed a dead bug covered with the fungus, and also 
healthy larve ; larvee just on the point of pupation; pup just prior to 
reaching the adult stage; and fully developed adults, each stage being 
placed on separate plants and each covered with a small inverted glass 
vial numbered by lettering. As checks, another series was prepared 
like the first in every particular. The soil in the box was kept weli 
moistened, and the plants remained fresh. This experiment was made 
on August 2, about the time when the attack outside began to diminish 
in intensity. The following are the results of examinations on the 
dates indicated, the original experiments being numbered by capitals, 
and the checks by small letters, thus—A-—a, adult; B—b, young larvee ; 
C-c, older larvee; D-d, pupe. 
Date. | A. | a. | Bo] ob Co alleexe Dn Weng ad 
— i | aes eee 
| 
Aug. 5 | ealthy | : Hewlthy | Healthy .- re Healthy -| 1 dead ...| Healthy -| 1 dead ...| 1 dead. 
Aug. 6 | 1 dead . 1 dead . --| Healthy | Healthy -| 1 dead ...| Healthy .| 3 dead ...| 1 dead. 
Aug. 7 | Alldead ..| 3dead .. | 3dead-..| 1 dead ...| 3 dead . Wdeatees|- soo a----|)| odeade 
Aug. 16 | All dead ..| All dead - | All dead. | Alldead | Alldead | Alldead | All dead | All dead. 
— uF a ee —— — 
