20 BULLETIN NO. 3, DIVISION OF ENTOMOLOGY 



EXPERIMENT NO. 5. 



September 22. — Twelve larvae of Plusia brassicce and four of Pionea 

 rimosalis were placed in one of the tin boxes and sprinkled in the usual 

 manner with Cutlers' No. 5, the powder which had given the best re- 

 sult in the last experiment. 



In 5 minutes the Pionea larvae were aifected, and in 10 minutes the 

 small Plusias ; the full-grown Plusias not until 25 minutes. The effects 

 upon all were very marked. The rectum was everted, and large quanti- 

 ties of a greenish liquid were ejected from the mouths of the Plusias. 



At 35 minutes two of the largest Plusias still appeared normal. The 

 skin of the Plusias being so delicate the heart beat was watched without 

 much difficulty. In the normal individuals the pulse was found to 

 range, after numerous trials, from 44 per minute to 68, averaging about 

 56. 



The pulse of one of the large worms in its first spasms marked 164, 

 and 8 minutes later it had fallen to 150, and in 15 minutes later still to 

 140. 



In a smaller one, which had passed through the first convulsions and 

 had become feeble, the pulse was almost imperceptible from weakness, 

 and though still very fast (136 per minute) had evidently fallen. 



At the expiration of 18 hours the Pioneas were all dead, and 4 of the 

 smaller Plusias were also dead. Two of the Plusias had spun up and 

 the remaining 6 appeared perfectly healthy and normal, The pulse of 

 these last varied from 44 to 64. 



September 24. — Three more of the larvae spun up, and the first two 

 transformed to healthy pupae. 



September 25. — The three larvae which spun up on the 24th have trans 

 formed to healthy pupae. 



*September 27. — The remaining larva which recovered from the dosing 

 is still strong and active. 



September 28. — This larva has also spun up and transformed to a 

 healthy pupa.' 



EXPERIMENT NO. 6. — EXPERIMENT WITH CUTLERS' "SPECIAL INSECT 



POWDER FOR ROACHES AND WATERBUGS. 



The base of this powder is Dalmatian pyrethrum, but from the odor 

 it apparently contains some red pepper. 



September 22. — A full-grown larva of HJyphantria to/orwas placed in 

 a closed glass jar and thickly dusted with this powder, which stuck to 

 the hairs in masses. It was seized with no convulsions, and September 

 27, after 120 hours, is still alive, though much shrunken and feeble from 

 starvation. The powder apparently had no effect upon it. 



September 22. — Four full-grown cockroaches were placed under an in- 

 verted tumbler, and a small quantity of this powder puffed in from an 

 insufflator. In 15 minutes all were taken with spasms, and in an hour 



