152 JOSEPH HALL BODINE. 



gomyia albopicta) found that the animals were killed at once in a 

 o.i per cent. HgCl 2 solution. This difference in length of time 

 of fatal exposure to this concentration from the present result is 

 doubtless due to the differences in resistance of the two species 

 as well as to the end point taken in the experiments. Sen evidently 

 used cessation of body movement while in the present investi- 

 gation cessation of movements of heart and alimentary canal 

 were taken as the end point. 



SUMMARY. 



1. Mosquito larvae (Culex pipiens} were found to be extremely 

 resistant to rather high concentrations of various acids. 



2. The order of toxicity of the acids used is, salicylic > oxalic 

 > HgCl > butyric > acetic. 



3. The chemicals seem to penetrate the animal orally and not 

 cutaneously. 



4. Animals withstand rather high concentration of HgCl 2 , 

 considerably in excess of that found for other organisms cited. 



LITERATURE CITED. 



1. Mac Fie. 



'21 Ann. Trop. Med. & Parasit., Vol. XV 7 ., No. 4, p. 377. 



2. Chidester 



'17 N. J. Agric. Expt. Sta., Bull. 299. 



3. Sen. 



'21 Rept. Proc. 4th Ent. Meeting, Pusa, Calcutta, p. 184. 



4. Sharma. 



'21 Rept. Proc. 4th Ent. Meeting, Pusa, Calcutta, p. 199. 



5. MacGregor. 



'21 Parasitology, Vol. 13, No. 4, p. 348. 



6. Honda. 



Journal Exp. Zoology (in press). 



7. MacArthur. 



'20 Am. Jour. Physiology, Vol. LIV., p. 138. 



8. Bodine. 



'23 Journal Exp. Zoology (in press). 



9. Jacobs. 



'20 Am. Jour. Physiology, Vol. LI, No. 2. p. 321 



10. Haas. 



'16 Journal Bio. Chem., Vol. 27, p. 225. 



11. Collett. 



'19 Journal Exp. Zoology, Vol. 29, No. 3, p. 443. 



