HABITS AND LIFE HISTORIES OF TABANIDiE. 



21 



Larvfe when tirst hatched were about 2 mm. in length; they grew 

 rather slowly, but in iifteen days after hatching had doubled their 

 length. They fed readily on the small crustaceans which were given 

 them. It was impossible to give these small crustaceans their proper 

 surroundings, so many of them died, and it was observed that the 

 young larvffi fed on these as well as on the specimens which they 

 killed themselves. The larvte could be seen crawling about in the 

 jars; they appeared to remain very near the upper surface of the sand 

 most of the time, and when food was scarce did much crawling, but 

 when food was plentiful satisfied their appetites and hid among the 

 plant material, where they remained quiet. 



A difference in size in the various larvae soon became apparent, 

 and the older they 

 became the greater 

 this difference. On 

 July 23, twenty-live 

 days after hatching, 

 some s p e c i m e n s 

 measured as much as 

 7 mm., while others 

 measured onl}^ 3 mm. 

 At this date angle- 

 worms were given 

 for food and were ac- 

 cepted readily, and 

 appeared to be as 

 satisfactory as the 

 crustaceans, but it 

 would seem that the 

 latter are preferable 

 for the stage just 

 after hatching. 



July 27 some of the larva^ were 10 mm. in length, and August 2 the 

 same specimens measured 12 mm. ; thus at this stage they grew more 

 rapidly than when they were younger. They fed actively till about 

 the middle of September, when they had become apparently full 

 grown, or 25 mm. long. Length in the larvie of tabanids is not a 

 satisfactory means of indicating the size, for the segments telescope 

 on one another in such a way that it is difficult to take two measure- 

 ments exactly alike, but an endeavor was made in this case to make 

 the different measurements similar, so I am satisfied that those given 

 are suflncient to indicate the comparative sizes of the different ages. 

 After the 15th of September the few specimens remaining alive buried 

 themselves in the sand of the breeding jars and were quiet most of the 

 time until the 10th of March, when one pupated, the adult emerging 



Fig. l.— Tabamis lasioplithalmus: A, male; b, female; c, pupa; d, ter- 

 minal abdominal teeth of pupa; e, undersized larva. All enlarged 

 (original). 



