30 



MISCELLANEOUS PAPEKS. 



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

 opportunity to investigate their surroundings. 



At hatching time nearly all the larva? 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. 



I proved to m}' satisfaction that 

 horsefly larva? are palatable to 

 the small catfish {Amiiirus ineJas), 

 although I am not fully informed 

 of how much value the fish is in 

 destroying them under natural 

 conditions. From a large num- 

 ber of these larvte, hatched July 

 21, 200 were counted out on the 

 morning of the 23d, and placed 

 in a quart jar of water containing 

 two young fishes slightly more 

 than an inch in length. Before 

 noon of the same day all the larvje 

 had been devoured. At another 

 time 300 \avxk were put into an 

 aquarium with 12 of the catfish, 

 with the r{\sult that the former 

 disappeared within the space of 

 an hour or two. 



Juh' 21 a number of larva? just 

 hatched were placed in a breed- 

 ing jar containing damp sand 

 covered over the top with fine 

 plant material, and small crusta- 

 ceans were put in for food. The 

 larva? took kindly to the sur- 

 roundings, accepted the food 

 otiered, and began to grow from 

 the start. After a couple of 

 weeks, as angleworms were much 

 easier to obtain, these were sub- 

 stituted for the crustaceans, with 

 no bad effects on the larva?, 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. 



Fig. 5.— Eggs of Tahanns stygius, showing: a position 

 in which tliey are not often found. From a pho- 

 tograpli (original). 



