14 PROC. ENT. SOC. WASH., VOL. 20, NO. l, JAN., 1918 



curious bits of information such as that concerning the use of 

 beetle larvae for arrow poison 1 or that in regard to the "manurial 

 value of locusts." 2 



At times there .are found references which may be regarded as 

 of interest to the chemical investigator in a negative sense, as in 

 the case of a paper which tends to show that insect coloration is, 

 at times, due to physical causes rather than to the properties of 

 definite chemical compounds in the form of pigments. 3 



A few papers were found which were of interest to the collector 

 primarily, such as those dealing with methods for preserving or 

 protecting collections or, in one case, a paper in which it was as- 

 serted that in baits for insects frequenting fragrant flowers it is 

 the sugar in the bait which attracts the insects. Experiments in 

 which various essences were used tended to show that fragrant es- 

 ."ennces, such as that of mint or the like, were without added 

 attractiveness. 4 



The remaining investigations may be classed under the heads 

 of biochemical and biological researches. With these we might 

 mention a few which dealt with vegetable products, such as 

 manna which, as with galls, may owe their formation or deposi- 

 tion to the work of an insect or to an insect poison or stimulant. 



Among the biochemical references are some dealing with 

 definite chemical compounds. Such are those giving the chemi- 

 cal composition of substances found in the bee, in its different 

 stages, or of the silk worm. One abstract of interest announced 

 the finding of certain carbohydrate ferments in species of Diptera 

 and Lepidoptera. 5 In other papers but a single compound is 

 mentioned, as for example urea, which is stated to be found in 

 insects generally, 6 the presence of calcium oxalate in crystals in 

 "la Blatte" (Cockroach), 7 and of formaldehyde as a protective 

 poison in the case of ants. 8 



In some instances the investigations, while of interest, have 

 led to less definite results, in a chemical sense, the exact nature 

 of the substances not having been determined. Examples of 

 this class may be found in studies dealing with pigments in beetles 

 and butterflies, 9 and the nature of the poisons of the browntail 



1 Trommsdorff, Arch. Schiffs-u-Tropenhuyg. 13, 617. C. A. G, 892. 



2 Anon., Bull. Impl. Inst., 14, 290-1 (1916). C. A. 10, 3132. 



3 Mallock, Proc. Roy. Soc. Lond., 85, 598-605. C. A. 6, 571. 



4 Plateau, Bull. Sci. acad. roy. Belg., 1910, 144-6. C. A. 4, 2664. 



5 Strauss, Z. Biol., 52, 95-106. C. A. 3, 1182. 



8 Fosse, Ann. inst. Pasteur 30j 642-76 (1916). C. A. 11, 1432. 



7 Hallez, Compt. rend., 148, 317-18. C. A. 3, 1284. 



8 Tzitovich and Smirnov, Compt. rend. soc. biol., 77, 122-3 (1914). 

 C. A. 11, 6(>(i. 



'Gortner, C. A. 5, 1921; 6, 893; Gebhardt, 7, 3797; Hasebroek, 10, 

 787. 



