48- 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



full-grown larva takes to sandy and powdery soil, and makes an oval 

 hollow. It spins a network with strong compound ribs and more delicate 

 tissue between these, and attaches this to little stones in the hollow. 

 Soil-particles also become entangled in the web. As the result of often- 

 repeated somersaulting movements it makes an oval cocoon. The first 

 pair of legs helps in the cocoon-forming. Damaged cocoons are repaired, 

 but not if the damage extends to half of the cocoon. An excised end 

 €an be replaced apart from the substratum, and in the absence of sub- 

 stratum-particles thick strands are made by compounding many single 

 threads. The plasticity of the instinctive behaviour is of great interest ; 

 the instinct is still capable of development. J. A. T. 



Poison of Predatory Hymenoptera. — A. Ch. Hollande (G.R. Soc. 

 Biol., 1920, 83, 9-11). Roubaud has maintained that the poison of 

 predatory Hymenoptera, such as wasps, has a twofold effect, producing 

 paralysis and preventing rapid decomposition after death. Hollande 

 has studied twenty-three paralyzed Geometrid caterpillars taken from 

 the nest of some Eumenid or the like. They were in perfect preserva- 

 tion, and they reacted to the touch of a needle by slight movements 

 of the end of the abdomen. Careful examination of the tissues showed 

 that the cells were quite normal in their staining reactions. But this 

 need not be ascribed to any preservative effect of the poison ; it is 

 simpler to suppose that while the poison anaesthetizes the nerve-cells the 

 ordinary cells of the body remain aUve. J. A. T. 



Australian Honey-ants. — W. M. Wheeler {Proc. Amer. Acad. 

 Arts and Sciences, 1915, 51, 255-86, 12 figs.). Observations on the 



Leptoniyrmex varians Emery var. ruficeps Emery, 

 o. Replete worker. 6. Head from above. 



singular ants of the genus Leptomyrmex. The worker is marked by the 

 extraordinary attenuation and elongation of all parts of the body 

 except the abdomen. There is a very high development of the pro- 

 ventriculus, which functions as a valve between the ingluvies or crop 

 and the ventriculus or true stomach. The insects have the habit of 



