174 THE EARLY STAGES OF TABANID^ 



layers one above the other. The color of the whole mass is brown, 

 mottled over the top with white. In these respects they do not 

 differ in particular from the eggs of other species of the genus, but the 

 masses observed were not so convex as those of Tahanus atratus, and 

 being placed on stones of a color similar to themselves are rather 

 difficult to see. Females have been observed ovipositing as early as 

 June 8, but most often eggs are deposited after this date. 



The larvae (Plate 3, Fig. 43) occur in the streams in the fall. Hine 

 states that in September and October each year they collected the 

 larvae of the dobson-fly (Corydalis corntUa L.) for study in the lab- 

 oratory. By turning stones at the edge of swift riffles, or by means 

 of a net stretched across the riffles to catch such specimens as are 

 dislodged by turning stones behind the net in the stream, in addi- 

 tion to Corydalis larvce, a large number of the larvae of this horse-fly 

 were found. Though having done much collecting in streams, Hine 

 asserts that the larva of Tahanus vivax is the only tabanid larva 

 taken in riffles so far. It was not found difficult to rear these larvas. 

 Larvae taken late in the fall were placed in damp sand and fed on 

 angleworms. As winter approaches they refuse to eat and remain 

 quietly in the sand until the following spring; then they feed actively 

 for a few days and change to pupae. They reach the adult stage in 

 late spring or early summer. Like other tabanid larvae, the larvae of 

 Tahanus vivax are not particular as to their food; all that appears to 

 be necessary is that they obtain small soft bodied animals. Crus- 

 taceans serve them as well as insects and their own species as well as 

 some other species — whatever, in fact, is in the sand of the breeding 

 cage. 



Hine has never observed the larvae in nature in the spring; conse- 

 quently their habits at this time of the year are not exactly known, 

 but Hine supposes that they leave the water and pupate in the 

 earth near at hand. 



Hine's description of the larva and pupa follows: 



''Larva. — [Plate 3, Fig. 43.] When full grown, about 25 mm. long. Gen- 

 eral color yellowish white, anterior margin of each thoracic segment and a narrow 

 band, including the prolegs, on the anterior half of the first seven abdominal 

 segments opaque, and appearing darker than the other parts, which are more or 

 less shining and usually finely striate longitudinally. Prothoracic segment di- 



