. Bulletin of the Department of Agriculture. Agriculture. 8 BULLETIN 986, U. S. DEPAETMENT OF AGRICULTURE. due to chiggers, were found to be due to Hyletastes missouriensis Ewing, a gamasid mite, the habits of which are not well known. Injury from fleas is very similar to the first-stage injury of chig- gers, and since fleas soon leave their hosts and chiggers are so small that they frequently are overlooked, flea injuiy is mistaken for chigger injury. A careful examination with a hand lens will enable one to see the attached chiggers and prevent confusion of flea injury with an attack by
. Bulletin of the Department of Agriculture. Agriculture. 8 BULLETIN 986, U. S. DEPAETMENT OF AGRICULTURE. due to chiggers, were found to be due to Hyletastes missouriensis Ewing, a gamasid mite, the habits of which are not well known. Injury from fleas is very similar to the first-stage injury of chig- gers, and since fleas soon leave their hosts and chiggers are so small that they frequently are overlooked, flea injuiy is mistaken for chigger injury. A careful examination with a hand lens will enable one to see the attached chiggers and prevent confusion of flea injury with an attack by chiggers. DO CHIGGERS PENETRATE THE SKIN? Both among entomologists and the public generally there is a belief that chiggers burrow into the skin. C. V. Riley {10) states in regard to his irritans that " This mite is able to bury itself completely in the flesh," In speaking of the same chigger, Osborn (5, p. 252) sys: "It is brushed from the leaves of various plants onto the hands or clothing of people and to the bodies of other animals, and the mite then proceeds to burrow into the ; To find out whether chiggers penetrate the skin or not, and also to observe their injury, resort was made to experimenta- tion. On July 15, 1919, the writer exposed the left calf and ankle to chigger attack, and after the mites had settled numbered 10 individuals by writing on the flesh near the mite with ink. Daily observations were made on these chiggers, using low and high power lenses, for the next eight days. It was observed on the first day that the mites attached only by their mouthparts and in no way burrowed into the skin. Observations on the second day showed no change; in fact, after once attaching to the skin by their mouthparts the larvae became quiescent and did not change their position until they dropped off. By means of a razor blade several individuals were removed by slicing off a small area of the epidermis around them. When this " slice" of e
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