1923 ENTOMOLOGICAL SOCIETY. 63 



three small nails, and the tanglefoot strip brought down to meet the glass, so 

 that the weevils crawling along the barrier are forced to walk onto the glass. 

 The tin is partly filled with water and about a cupful of coal oil is poured on top. 

 The traps are more effective if the glasses are kept well cleaned. The weevils 

 either fall directly into the trap or walking on the glass slip off that into the water. 

 It has been found necessary to fix a "leader" or strip of wood at each side of the 

 glass to induce the weevils to walk on it. These strips are the same thickness 

 as the glass where they touch it and are bevelled to a thin edge at the other side. 



Recently the efficiency of these traps was strikingly illustrated. A grower 

 had placed a tanglefoot barrier around two sides of a badly infested plot of 

 about one acre in extent to prevent the weevils from crossing onto newly planted 

 land adjoining. A trap as above described was placed at each end of the barrier 

 and one in the angle at the corner of the plot. The corner trap (No. 1) was 

 put down in the first week in July and those at the ends (Nos. 2 and 3) on the 

 12th of August. The number of weevils destroyed was extraordinary. The 

 traps were cleaned out on September 1st and about two quarts of weevils were 

 taken out of No. 1 and half the quantity out of No. 2. After the weevils had 

 been dried and foreign matter removed, the numbers were computed by dividing 

 the weight of 6,000 weevils, carefully counted, into that of the bulk. According 

 to this method there were approximately 44,660 weevils in trap No. 1, and 17,000 

 in trap No. 2. Trap No. 3 was not counted, owing to the putrid condition of 

 the contents, but there were fully as many as in trap No. 2. Consequently the 

 total number of weevils caught in these three traps could not be far short of 

 80,000. In each trap there were several dead mice, and in one the remains of 

 a bird and a lizard. Their putrefying bodies gave an odour to the entire contents 

 which made the job of counting amost unsavoury one, so that after completing 

 the examination of traps 1 and 2 the writer concluded that he had done enough. 



The following is an analysis of the different kinds of insects caught and it 

 shows that the number of useful species destroyed is not very appreciable: 



Trap No. 1 (in use for 2 months) 



O. ovatus 44,660 Spiders 15 



Other weevils 33 Hymenoptera 5 



Carabidae 77 Hemiptera 4 



Silphidae 11 Termites 4 



Staphylinidae 1 Coccinellids 6 



Sow Bugs 60 Grasshoppers 3 



Lamellicorns 19 



Trap No. 2 (in use for 3 weeks) 



O. ovatus 17,000 Sow Bugs 32 



Other weevils. . . .' - 17 Spiders 4 



Carabidae 33 Hemiptera 26 



Silphidae 5 Coccinellids 2 



Staphylinidse 8 Diptera 1 



The second type of barrier combines the advantages of a barrier and trap 

 in one. It is constructed of heavy lumber, usually 2" x 10" with a V-shaped 

 groove in the upper edge. The groove is X 1 /^ inches deep and 1 inch wide, It 

 is supported at the joints by 2" x 6" posts, and the ends of the groove are blocked 

 and rendered oil tight. The groove is filled with crude oil of the typeused forspread- 

 ing on roads. This kind of barrier needs very little attention, beyond seeing 

 that the groove contains sufficient oil and that leaks do not occur. It has the 

 disadvantage that it can only be used on level or nearly level land and on sloping 

 land it must be built in steps to keep the troughs level and a little tanglefoot 



