ENTOMOLOGY

444 SANITARY ENTOMOLOGYsomewhat more resistant to arsenical dips than the cattle tick, and it,vas found best to add kerosene emulsion to the arsenical, following theWatkins-Pitchford formula. In order to prevent the dropping of repletefemales, the dipping must be practiced at weekly intervals. Fortunatelythe spotted fever tick confines its activity in the adult stage to the springmonths, so that it is not necessary to continue the dipping later thanabout the first of July.Since practically' all of the immature stages of this species developon small rodents, notably the ground squirrels, wood rats, pine squirrels,rabbits, etc., the importance of rodent destruction, both from the standpointof tick control and protection of crops, is apparcnt. In much ofthe territory where the spotted fever tick abounds, it is, however, impracticableto reduce the number of rodents to a very low point. In othel;words, in the scheme of eradication dipping of live stock should comefirst and the destruction of rodents be taken up as a secondary step.Aside from the destruction of this tick on animals, it is necessary forman to protect himself against its attack. This can be accomplished tosome extent by avoiding cut-over woodlands or brushy areas, by wearingclothing calculated to exclude the ticks arid by examination of one'sperson at frequent intervals. It was found by Dr. Ricketts that a tickmust be attached to a guinea pig for one hour or longer to produce thedisease, thus it would seem that there is li,ttle danger of infection in manif the ticks are removed promptly. Since no successful remedy for thetreatment or prevention of the disease has been devised, the importanceof exercising care in preventing infection by keeping free of ticks can notbe too strongly emphasized.The Spinose Ear Tick.-We are concerned with this species both onaccount of its injurious effect on horses, cattle, dogs, and other animals,and the frequency of its attachment in the ears of man. Furthermore weshould be familiar with this tick since a considerable part of our militaryactivities in this country have been and will probably continue to be inthe Southwest where the species abounds:It is probable that by exercising some care in locating camps and inchoosing places for sleeping, some degree of immunity from attack willresult. The seed ticks are, of course, concentrated about feed lots,corrals and watering places of live stock and these should be avoided inchoosing a camp site.The effect on animals of heavy infestations of this species is verymarked. The ears are droopy, the hair rough and the animal presentsan unthrifty appearance. Fattening is difficult if not impossible, andunder range conditions the loss by death is not infrequent. In horses andmules there is' a marked shyness on the·part of the animals when attemptis made to touch the ears or put _on a bridle. This is sometimes so extreme