- 512 - 
HARTZELL, A., and TCILCOXOH, F. (2168) 
1932. EXPERIMENTS ON THE MODE OE ACTION OP PYRSTHRUM AND ITS EFFECTS ( 
INSECT TISSUES. 5th Cong. Internatl. Ent . July. 289-293. [Abstrac| 
in Chen. Abs. 28: 5537. 1934.] 
Nerve ganglia of insects killed "by pyre thrum showed histological 
changes, hut insects killed by decapitation, nicotine sulphate, or 
lead arsenate showed no histological changes. 
HARTZELL, A- , and T7ILCCXCN, F. (216 9) 
1932.- SOME FACTORS AFFECTING THE EFFICIENCY OF CONTACT INSECTICIDES. 
II. CHEMICAL AND TOXIC0L0CICAL STUDIES OF PYRETHRUM. Contrih. Boyce 
. Thompson Inst. 4 (l); 107-117, illus. 
Nicotine (l drop c.p.) put on. the last abdominal segment of 
a tomato worm ( Phlegethontius quinquemaculata Haw.) did not lead to 
death, hut violent intoxication took place (p. 114). 
HOCKENYOS, &., and LILLY, J. (2170) 
1932. TOXICITY STUDIES OF HYPODERMIC INJECTION OF CELSRIO LINEATA LARV 
Jour. Econ. Ent. 25 (2): 253-251, illus. [Abstract in Rev. Appl. Ent 
(A) 20: 417. 1932.] 
The data secured indicate that for both organic and inorganic 
materials there often appears to he an optimum point of dilution at 
which they can he most efficiently used. Thus 0.0006 cc. of pure 
nicotine was injected in one case as 0.03 cc. of 2 percent dilution 
and in another case as 0.06 cc. of 1 percent dilution, the latter 
proving consistently more efficient than the former. Some possible 
reasons for this are suggested. The speed for paralyzation of a larva 
injected with nicotine sulphate of a given dilution was in direct 
proportion to the distance from the point of injection to the head. 
Thus larval muscle co-ordination. is shown to be centered in the brain. 
McC-OVRAN, E. R. (2171) 
1932. THE EFFECT OF SOME GASES ON THE TRACHEAL VENTILATIOU OF GRASS- 
HOPPERS. Jour. Econ. Ent. 25 (2): 271-276. [Abstract in Rev. Appl. 
Ent. (A) 20: 418. 1932 •] 
Nicotine in certain concentrations, used as a gas, increased the 
volume of air inhaled into the tracheal system by the respiratory 
movements of a number of grasshoppers. 
i/IISAKA, K. (2172) 
1932. ON THE EFFECT OF NICOTINE SULPHATE ON THE EMBRYONAL DEVELOPMENT 
OF CHI LP SIMPLEX BUTLER. Imp. Agr. Expt . Sta. Bull. 3 (3): 225-242,1 
illus. [Tokyo] [Abstract in Rev. Appl. Ent. (A) 20: 433. 1932.] 
