285 



after the fly-free date and co-operation amongst growers. The records 

 of various fields examined are tabulated with regard to compliance 

 with these conditions. The figures given show clearly that the degree 

 of infestation by the spnng brood depends directly upon the amount 

 of self-sown wheat present at seeding time, and the importance of 

 destroymg this cannot be over-emphasised. Sowing after the fly-free 

 date undoubtedly proved an important factor in control, though 23 

 per cent, of the fields included in the survey escaped with slight iniury 

 in spite of having been sown before the fly- free date, and after having 

 been heavily infested in the autumn and consequently producing a 

 large part of the spring brood which damaged wheat throughout the 

 county. The burning of stubble appears to have but little importance 

 as a factor in control. 



Hayes (W. P.), Studies on the Life-history of Ligyrus gihbosus, DeG. 

 (Coleoptera). — Jl. Econ. Entom., Concord, N.H., x, no. 2, April 

 1917, pp. 253-261, 1 plate. 



This paper contains additional information with regard to the life- 

 history of Ligyrus gihbosus, about which little has previously been 

 published [see this Review, Ser. A, iv, p. 284]. A table is given 

 showing the length of the various stages, each of which is 

 described. Adults that have hibernated are found as early as 4th May 

 and oviposition begins towards the end of the month. The larvae 

 hatch in about 10 days and have been found feeding on the roots of 

 maize, oats and wheat. They also thrive in soils that are rich in 

 decaying organic matter, such as pasture land and freshly manured 

 fields. In rearing cages, the larvae were frequently observed to devour 

 each other. All stages of the beetle are found in the soil, but adults 

 are attracted to lights at night. Natural enemies of the beetle are 

 the common toad [Bufo (iinericana), and certain birds. Three species 

 of Sarcophagid flies, Sarcophagu helicis, S. cinibicis and ;S'. rudis, have 

 been bred from dead adults. The grubs are attacked by two distinct 

 bacterial diseases. 



No satisfactory method of control can be given for this species. 

 The host-plants are numerous, the adults attacking potatoes, sun- 

 flowers, dahlias, sugar-beet, oak, carrot, cotton, maize, parsnip, celerv 

 and elm, while the larvae attack pigweed, sunflower, wheat, maize 

 and oats. Autumn ploughing is useless miless undertaken early 

 enough to break up the pupal cells, for the adults, when disturbed, 

 can easily dig into the loosened soil again. It is advisable not to plant 

 maize in freshly broken pasture land, in view of the preference of 

 both grubs and beetles for this kind of soil. 



SivHTH (H. S.). On the Life-history and Successful Introduction into 



the United States of the Sicilian Mealy-bug Parasite. — Jl. Econ. 



Entom., Concord, N.H., x, no. 2, April 1917, pp. 262-268, 2 plates. 



The successful introduction of Paraleptmnastix abnormis, Gir., a 



Chaicidoid parasite of Pseudococcus citri, into the Calif ornian orchards 



as a control of the mealy bug, has already been recorded [see this 



Review, Ser. A, iv, p. 51]. This paper describes the various stages of 



the life-history of the parasite and the methods of rearing and 



colonising it. The younger stages of the mealy bug are preferred as 



hosts, the newly emerged adult depositing eggs immediately into the 



