ZOOLOGICAL DEPARTMENT. 399 



It is made of light slieet iron ten to fifteen feet long by about three feet 

 wide. The front should roll up half an inch or an inch to give a smooth 

 face, while the back should be from six inches to a foot deep and side 

 pieces to correspond. The inside of the pan should then be coated nearly 

 half an inch deep with coal tar, and with a rope attached on either side 

 the dozer is ready for use. Two persons can easily run such a pan, but 

 horses may readily be attached to a larger one. The principle is all that 

 is necessary to suggest and then each one can arrange details to suit the 

 occasion. Whatever is used to draw the hopper dozer should be at either 

 end, else the locusts would be driven each side before the tarred pan 

 reached them. Of course at the approach of the machine the locusts leap 

 and usually alight on the tar. The winged ones may fly entirely over, 

 and often a stiff wire or stick placed a few inches in front of the dozer 

 will help, as the plants will be stirred and start the locusts up sooner and 

 drop them where desired. If very numerous, the insects will soon cover 

 the tar, so that an occasional new supply will be needed. It is best of 

 course to use the hopper dozer on the locusts as soon as they are noticed 

 in numbers. At this time they will not be full fledged and can be caught 

 easier. If they are mostly winged ones, fewer would escape if taken in 

 the cooler parts of the day when they are not so active and are more apt 

 to hop than fly. For pastures, and meadows with shoi't grass, no runners 

 are needed under the hopper dozer, but for peppermint and such plants 

 that are higher and more tender, runners that will raise it high enough not 

 to break the plants may be easily put on. They can be placed so as to 

 run between rows at any distance desired. By going over the badly 

 affected fields in this way several times at short intervals, a great deal is 

 saved at a slight expense. At the Iowa station it is estimated that even 

 where all the help is hired, the expense of each collecting does not exceed 

 ten cents per acre.* 



A good deal may be done in the way of prevention by plowing and cul- 

 tivating land known to be breeding ground for the locusts. Many of the 

 egg cases are broken by plowing and working the soil, and the egss are 

 much less liable to hatch. Should they hatch, the young are unable to 

 penetrate soil well packed over them, and for this reason thorough culti- 

 vation with frequent rolling of such fields is to be commended. Dead 

 grass, rubbish, etc., serve as a winter protection and should be cleaned up 

 or burned in the autumn. 



G. C. DAVIS. 



THE HORN FLY. 



Haematobia serrata. 



Oedek DIPTERA. Family MUSCIDyE. 



A small two-winged fly that is likely to appear in swarms on stock this summer and to be very 

 annoying to them by its bite, causing them to lose in flesh and flow of milk. 



The spread of this stock pest over the State this year seems certain. 

 Less than five years ago it was unknown to the United States. In the fall 

 of 1887 it appeared in southern New Jersey, but was not numerous enough 



*Bnlletin No. 14, of the Iowa Agricultural Experiment Station, page 172. 



