282 



All stages of the insect are described. The duration of the egg- 

 stage varies according to climatic conditions, the average being 9 or 

 10 days. The larvae moult eleven times. Their habits are subter- 

 ranean, and they show a preference for dry soil. In the autumn they 

 are found at the bottom of the drill rows and in the spring just beneath 

 the surface of the ground. They also feed on roots and seeds of 

 grasses and on decaying matter and occasionally prey on each other. 

 By October they are practically full-grown and hibernate in this 

 stage. Early in the spring they moult again, and prior to pupation 

 they enter a quiescent state lasting about a week. The total length 

 of the larval stage averages about 317 days. 



Pupation occurs in the field during April, May and June, lasting 

 on an average almost 14 days. 



The first adults emerge in May and are found in the field until 

 the middle of October, reaching a maximum in August. The normal 

 duration of life is from 2 to 4 months. Pairing usually takes place 

 early in July, followed in a few days by oviposition, the last occasion 

 on which this was observed being in October. The beetle is nocturnal 

 in habits and feeds in the field on evening primrose, Russian thistle 

 and lucerne, and like the larvae they are sometimes cannibals. 



A Hymenopterous parasite, Perilitus eleodis, Vier., has been reared 

 from Eleodes opaca, but the percentage of parasitism has never been 

 high. A Gregarine, Stylocephalus giganteiis, was found in the alimen- 

 tary tract of the beetles. In the cages a great many larvae succumbed 

 to a bacterial disease, and the fungi, SporotricJmm globulifervm and 

 Metanhizium sp., have been found to attack them. 



The cultural methods to control this pest include rotation of crops, 

 summer fallow and delayed planting. A large number of pupae 

 may be destroyed by spring ploughing, thus exposing them to natural 

 enemies and climatic conditions. A poison bran-mash may prove 

 beneficial against the beetles, but all attempts at poisoning the larvae 

 have been unsuccessful. 



RiCKER (D. A.). Experiments with Poison-Baits against Grasshoppers. 



— Jl. Econ. Entom., Concord, N.H., xii, no. 2, April 1919, pp. 

 194-200. 



Climatic conditions play an important part in the efficacy of poison- 

 baits against grasshoppers, and as a result of experiments made in 

 Wisconsin the most favourable conditions appear to be a rather 

 low temperature and high humidity. Various baits were tried, and 

 a table showing their respective efficacy is given. Apples and bananas 

 when used alone or with molasses are sUghtly more attractive than 

 lemon fruit or lemon extract. A distinct advantage of fruits other 

 than those of Citrus is that their odour lasts longer and even increases 

 as fermentation progresses. This fact is of special value with regard 

 to young grasshoppers, as they respond better to a strong -smelling bait. 



Paris green, crude arsenious oxide and calcium arsenate were the 

 three poisons tried, the mortality resulting from each of these being 

 nearly the same. In treating tobacco, Paris green caused scorching, 

 but calcium arsenate did not. 



The rate of application should depend upon the infestation and the 

 attractiveness of the bait ; standard bait used at the rate of 6 to 8 lb. 

 to the acre gave efiective results. 



