164 THE EARLY STAGES OF TABANID^ 



vantageous no doubt, for food is not always at hand, and in case it 

 is not, the fact that nourishment is furnished naturally gives them 

 an opportunity to investigate their surroundings. 



At hatching time nearly all the larvae that come from a single mass 

 of eggs appear at the same time and when they have freed themselves 

 from the shells, go tumbling down into the water, scattering more or 

 less and sinking to the bottom, where it is difficult to observe their 

 further actions. 



Hine found that small catiishes (Ameiurus mclas) are enemies of 

 these larvae, and he observed two of them devour 200 young larvae 

 of Tahanus within a few hours. 



Hine's attempt to rear the larvae from the egg to the adult was not 

 successful. On July 21, a number of larvae just hatched were placed 

 in a breeding jar containing damp sand covered over the top with fine 

 plant material, and small crustaceans were put in for food. The 

 larvae took kindly to the surroundings, accepted the food offered, 

 and began to grow at once. After about two weeks, as angleworms 

 were much easier to obtain, these were substituted for the crustaceans, 

 with no bad effect on the larvas, which continued to grow, though 

 rather slowly. The largest attained a length of about 10 mm. by the 

 beginning of winter, when they ceased eating. They appeared to be 

 in good condition in the spring, but for some reason died without 

 further increase in size. 



On August 2, of the same year, Hine took a large larva of this 

 species in Summit County, Ohio, from under a flat stone along a 

 brook that ran from a spring. When taken this specimen measured 

 over 40 mm. in length and had every appearance of being mature, 

 but it continued to eat the anglewonns given it until late in the 

 fall. It then ceased feeding until the following spring, when it took 

 a small amount of food and entered the pupal stage about the middle 

 of May, the adult, a male, issuing June 14. 



Hine thinks that it is hardly possible that this species passes all its 

 transformations in a single year, for the larvae reared from eggs were 

 not over 8 mm. long when the specimen over 40 mm. long was col- 

 lected; and as the latter did not produce the adult until about the 

 normal time for adults to appear under natural conditions, it does 

 not seem possible that the first mentioned larvae could have reached 

 maturity and produced adults before the second year. 



