ENTOMOLOGY

MYIASIS-TYPES OF INJURY, LIFE HISTORY, HABITS 187These infestations probably come about through the accidentaldepositions of eggs on the bodies or clothing of man, especially children.The possibility of this method of infestation is emphasized through theexperience of Dr. Glaser, who while studying ox warbles in Germany had afly deposit an egg on his trousers which in due time hatched and theyoung larva penetrated the skin of his leg. Later its presence in theoesophageal region was detected by an uncomfortable feeling. The larvaapparently passed up the oesophagus and later was extracted at thebase of one of the molar t~eth.In instances where the Oestrid fly of the genus Gastrophilus attacksman the conditions surrounding the infestation as well as the exactidentity of the larva arc less well understood. It is supposed that theyopng larvle are in some way brought in contact with the mucous mem-FIG. ST.-Full grown larva of the human bot, Dtwmatobia hominiB.Bradford.) Actual length 14.5 mm.(Drawing bybranes of the lips, mouth or eyes and penetrate them, later appeari~gunder the skin: and moving about in a manner somewhat similar toHypoderma. The life history of the species of this genus will be discussedunder intestinal myiasis.AMERlCA.-In America in addition to the Hypodermas we have amongthe lower mammals dermal myiasis produced by several different speciesof Oestrids in the genus Cuterebra. These are most commonly met within rabbits, squirrels and certain field mice. Usually they appear to causeno serious injury except in the case of one form, which is prone toattack the testicles of squirrels and was given the name of Cuterebraemasculator Fitch (equals C. fontilnella Clark).In South America a very interesting and more important form ofmYIasIs In man occurs. This is produced by the Oestrid, Dermatobiahominis (Carl Linne, Jr.) (noxialis Goudot, cyaniventris, Macquart)(fig. 37). This form appears to be normally the parasite of cattle, horses,donkeys and certain wild animals. It is reported as being a serious pest