68 FIRST REPORT ON ECONOMIC BIOLOGY. 



A view largely held by farmers and others that the larvae hatch 

 and creep about the skin, is also without any supporting evidence. 



So far as I can learn Osborn (op. cit.) was the first to definitely 

 establish the fact that the eggs were not taken into the horse's mouth, 

 and that in addition they required friction in addition to warmth and 

 moisture. In his experiments, however, he does not seem to have 

 taken into consideration the possibility of newly-laid eggs containing 

 larvae. 



The object, therefore, of the experiments here recorded is to verify 

 or otherwise those made by Osborn. 



A. The first batch of eggs were taken a few hours after being 

 deposited. 



1. A number of hairs with eggs attached were placed in a glass 

 jar in which a damp sponge was suspended from the rim of the jar, 

 but not in contact with any of the eggs. A temperature of 80 to 

 85 F. was maintained by means of a water batch. On the twenty- 

 third day two eggs hatched and twenty-two remained unhatched on 

 the fortieth day. When examined the larvae were all found to be 

 dead. 



2. The above experiment was also tried with eggs from batch 

 A, leaving out the damp sponge. On the twenty-second day two 

 eggs hatched, and the remainder were kept under observation for 

 nearly five weeks, but no further hatchings took place. 



3. A third experiment was made with some of the eggs of batch 

 A as follows : A bundle of the hairs were tied together and tied to a 

 piece of canvas tacked on to a piece of wood, which was allowed to 

 hang outside exposed to the rain and sun. There were fifty-seven 

 eggs, and at the end of twenty -one days only one egg was observed 

 to have lost its operculum. They were examined daily to the end of 

 the eighth week, when fifty-four eggs remained. 



4. A fourth lot of eggs, similar to batch A, and may therefore be 

 included here, were tested by first fixing the hairs to a piece of cloth 

 and carefully wiped over with a piece of close, damp sponge. One 

 half of the eggs were left untouched until the thirtieth day. On the 

 twelfth day five eggs hatched, and the larvae adhered to the sponge, 

 on the fourteenth day fourteen hatched, on the sixteenth dav twenty, 

 on the eighteenth day nineteen, on the twentieth day twenty, on the 

 twenty-fourth day four, and on the twenty-eighth day one, a total of 



