45 
such roots, plants, flowers, and fruits as might, upon experimentation, 
prove to have insecticidal properties. This was undertaken with a view 
of discovering if possible some product easily grown in the infested 
regions through the cultivation of which it might be possible to pro- 
vide for an insecticide which would be cheap and accessible to all. 
From these various collections Professor McNeiil has made numerous 
extracts, emulsions, and decoctions, some of which he informs me are 
quite promising, and which are on hand to experiment with when oppor- 
tunity offers. As this part of the work has, therefore, not been com- 
pleted for the reasons stated, I shall at present give only a summary of 
Professor McNeill’s letters and report of progress during the past sea-_ 
son. 
(1) Alcoholic extracts and decoctions have thus far been, on the 
whole, unsatisfactory. 
(2) Extracts and extract emulsions of the various vegetables or parts 
thereof seem to be promising. Of these kerosene, kerosene ether, gas- 
oline and benzine extracts, and emulsions of pyrethrum are perhaps 
most important. 
(3) Of the plants experimented with, Lobelia syphilitica, L. cardi- 
nalis, probably L. inflata, and Arisema triphyllum are among the more 
important as giving promise of good results. They have been shown 
to possess insecticide properties, but to what extent and how best 
utilized remains an open question, 
(4) An exceedingly dilute solution of potassium cyanide is an effi- 
cient insecticide, but its effects on the cotton plants has not yet been 
determined. 
METEOROLOGICAL CONSIDERATIONS. 
Of these rain, humidity, and temperature are the principal phenom- 
eva to consider. What relation these may have to the various stages 
of the transformations of Heliothis, the following tabulated data may 
serve to indicate. The averages of humidity and temperature are given 
for the entire period covered by each example: 
PAB TR IX. 
EGG. 
| Dura: Rain, Temperature.| Humidity. 
When deposited. When hatched, nam ber’ 
of days. Max.) Min. | Max.) Min, 
° c ° ° 
Night, Aug. 5-6........ | Aug. 10, 10a.m........ ie 34 | 2| 93 74 88 56 
Night, Ang. 8-9........ f Ane, 1026 Venn soe ae oscce= on | 0 | 94 73 87 63 
Night, Aug. 14-16...... b Anrst8 O'acmie:.-sce,cyoa545- 3 | 1 BO Wer 72 lark) (*) 
Night, Aug. 15-16...... AGTES ICI Eas nee oSgscaccOre 22 0 | 84 | NENA, () 
Night, Sept. 19-20...... Sept. 24, evening ........--.- 5 | 5 |p 79 Cri GC) (*) 
Night, Sept. 20-21...-.. Sept..25, morning. =.-22+2--2. 44 | Tales 64) (*) C) 
Night, Sept. 21-22...... Sept. 25, morning...........- 33 | 4 | 77 67 | (=) (*) 
* Data for humidity at Holly Springs, Miss , could not be obtained. The first two are from Shreve- 
port, La., where eggs were under observation. 
