426 



on evergreen trees are less rhythmical in their hibernation than those 

 which feed on deciduous trees. (3) Exposure may determine the 

 elasticity of the periodicity. Thus Isia isabella, which hibernates 

 under stones in a rather exposed condition, has a definite period of 

 hibernation, while the army worm [Cirphis unipiincta], w^hich 

 hibernates deep in the ground, does so only upon direct stimulus. 

 These three factors may also determine the stage or stages in which 

 different species of insects hibernate. Tables are given bearing out 

 this hypothesis. Investigations into the life-histories of the Tortricids 

 of European forests show that those species which feed on the outside 

 of the tree hibernate in a resistant stage, that is, as eggs or pupae, 

 whereas those which feed on the inside of the tree, and are thus 

 protected, hibernate as larvae. 



General conclusions reached by these investigations are that insects 

 hibernate as adults when their food habits are such that oviposition 

 can take place on suitable material at the first warm weather ; as 

 larvae, when protected from the cold and thus able to continue feeding 

 to the latest date possible ; and as pupae or eggs, because they are the 

 non-feeding, resistant stages. There is no evidence to determine 

 whether these adaptations were established by selection, mutation or 

 inherited tendency. Hibernation has, however, obviously resulted 

 from the repeated effect of Avinter upon the species, and the degree 

 to which this phenomenon has become rhythmical has been determined 

 bv the habits of the insect. 



MuiR (F.). The Introduction of Scolia manilae, Ashm., into the 

 Hawaiian Islands. — Ann. Entom. Soc. America, Columbus, Ohio, 

 X, no. 2, June 1917, pp. 202-210. 



Scolia manilae, Ashm., is being successfully established in Hawaii 

 as a control for Anomala orientalis, Waterh., and Adoretus tenui- 

 macitlatus, Waterh., the former beetle is a pest that injures the roots 

 of sugar-cane and has been found very difficult of extermination owing 

 to the total absence of any of its natural enemies in Hawaii ; the latter 

 constitutes one of the worst garden pests of the Islands, doing much 

 injury to roses and ornamental shrubs. As these pests were both 

 introduced from Japan, where Scolia is an important factor in control, 

 it was decided to attempt the introduction of S. manilae into Haw^aii. 

 Grubs of Anomala or Adoretus, which bore an egg of *S. manilae, were 

 placed each one in an artificial mud cell and the entrance closed with 

 mud. The cells were packed in moist soil in tins with close-fitting lids 

 and the tins in wicker baskets or boxes were shipped from Manila to 

 Honolulu. By the time their destination was reached, the Scolias 

 had pupated and the cocoons were then placed in damp moss and the 

 adults, when hatched, mated in captivity. In all, many thousands of 

 Scolia have been shipped to Honolulu, and although it will not 

 be possible to estimate their effect on Anomala and Adoretus before 

 the end of the present year, it is evident that the parasite is well 

 established and prospects of control are good. Experiments with 

 Tvphia, tw-o species of Prosena, a Dexia and a Campylotheca, and also 

 with several predators, have given less satisfactory results. 



