58 



Pitfshunjh Despatch of A^ugust 17 contaiued an interview with Dr. John 

 Hamilton, who stated that the abundance of grasshc^ppers in the 

 vicinity of Pittsburgh was due to the extended drouth, hardly a drop 

 of rain having fallen since July 3. The second week in August wheat 

 and oats in the vicinity of Newark, Ohio, were damaged, and corn near 

 the lower end of Seneca Lake, N. Y. 



THE BOT-FLY OF HUMAN BEINGS. 



Apropos of our editorial review of Prof. Blanchard's summary of the 

 Oestridoe which burrow beneath the skin of man, we may mention an 

 interesting communication which we have just received from Mr. David 

 Logan, now connected Avith the Gypsy Moth Commission, of Massachu- 

 setts. Mr. Logan writes us that he has been familiar with the species 

 having this disagreeable habit, first in Honduras on the Rio Tinto, but 

 more abundantly on the Rio Magdalena, near Mompos and uj^on the 

 River Sinu, 30 leagues south of Carthageua, in the United States of Co. 

 lombia. In his ninteen years' experience in troi)ical forests he estimates 

 that he has had at least a hundred of these parasites in different parts 

 of his body and at one time had eighteen of the maggots squeezed out 

 of his back. He had been for weeks in the woods hunting mahogany, 

 and there were neither cattle nor people anywhere around. It was, in 

 fact, in a perfect wilderness. He is in doubt as to whether the eggs are 

 laid on the skin or upon the bushes and come off upon the clothing of 

 people passing. Naked Indians, he states, had not one-tenth as many 

 as whites who wore shirts. 



Mr. Logan further states that the natives believe that the grubs are 

 produced by a species of yellow mosquito, and have named the larva 

 gnsano de mosquito. The back and shoulders of human beings appear 

 to be specially subject to attack, although the gusano sometimes shows 

 itself in other places, and Mr. Logan was once attacked in the upper 

 lip. The first evidence of the presence of the grubs in the skin is the 

 appearance of a little swelling resembling a small boil, not painful, but 

 giving to the victim a feeling of uneasiness. On close observation a 

 minute orifice may be seen in the center of this swelling. When first 

 detected the larva is usually of about the size of a pinhead. It works 

 chiefly at night and not continuously, but intermittently. Mr. Logan 

 had never kept specimens in his person for study or experiment, but at 

 one time had one for about six weeks in his shoulder. It was at this 

 stage at least an inch long when contracted, and when elongated about 

 an inch and a quarter in length. There were rings around the body 

 apparently covered with minute hairs or spinules, the body being nar- 

 rowed at the ends and nuich thicker than the head. The common remedy 

 adopted was to place a i)iece of leaf tobacco over the perforation in the 

 skin, and soon after the maggot could be squeezed out. 



As to the deposition of the eggs we have information from other ob- 



