covered witli a wdre gauze large enough to allow L. sericata to 

 enter, but excluding the blue-bottles — and a close fitting weather- 

 proof cover. The bottom of the pan is slightly dished, has a plug 

 in the centre, and contains a bed of sand. Above this swings a flat 

 saucer-shaped pan, in which the bait, consisting of raw meat, is placed. 

 The flies, attracted by the odour, pass through the gauze, and, once 

 inside, deposit their eggs and die. On hatching, the maggots crawl over 

 the edge of the dish and fall into the sand where they bury themselves. 

 When the pupal stage is reached the plug is removed and the sand is 

 pushed out into a sieve in order to separate the pupae. To be successful, 

 this apparatus must be baited with matter attractive to the fly and 

 must be placed in a position where the odour of its contents will be 

 carried by the air currents across the field occupied by the sheep. 

 Where the space to be controlled is extensive, more than one decoy 

 may be required. As the pupae may develop in 21 days from the date 

 on which oviposition occurred, the sand must be sifted every 14 days 

 to remove them, and they may be fed to poultry at once, or kept at a 

 temperature under 50° F., or reserved for future use after steaming. 

 Sheep that have been badly worried by maggots before the arrival of 

 the decoy should not be left as a test for the apparatus, as they are too 

 attractive. This decoy is said to be proof against rats, dogs, etc. 

 To prevent damage to herbage, it is mounted on two legs and a wheel 

 fork and it can be quickly moved, by one person, from one part of a 

 field to another. 



Cook (F. C.) & Hutchison (R. H.). Experiments during 1915 in the 

 Destruction of Fly Larvae in Horse Manure. — U.S. Dept. Agric, 

 Washington, D.C., Bull. no. 408, 28th October 1916, 20 pp. 



This is a record of further experiments on the same lines as those 

 previously conducted [see this Review, Ser. B, iii, pp. 192-193], and is a 

 summary of three years' work. The same methods and the same 

 cages were used as before, but in the case of the open-pile experiments a 

 pyramidal cage with a flytrap at the top was placed over the heap 

 immediately after the last treatment, and all flies collected in the traps 

 were chloroformed and counted. Experiments were made with. 

 infusions of poisonous plants, using 1 lb. to 10 U.S. gallons of water, two 

 of the more effective being berberis and cinchona. Quassia was found 

 effective only when used in large quantities. Black hellebore, larkspm', 

 soapweed, and many others were tried without proving of great practical 

 efiiciency. 



Tables are given showing the relative larvicidal value of various 

 fertilising mixtures. Calcium cyanamide, kainit and acid phosphate, 

 used in various proportions, proved an ideal fertiliser, but the larvicidal 

 results were all low and irregular, varying from 10 to 81 per cent. 



As a result of three seasons' work, it appears that borax is the best 

 and cheapest larvicide, though excessive application has an injurious 

 action on plant growth. Powdered hellebore is effective and has no 

 action on plants ; the cost is variable. Solutions of aniline and emul- 

 sions of nitrobenzene with fish-oil soap also proved eftective larvicides 

 and did not apparently injure the manure for agricultural purposes. 

 It is indicated that calcium cyanamide, acid phosphate and kainit 

 mixtures are effective larvicides, if one-half pound of calcium cyana- 



