102 THE EARLY STAGES OF TABANID.E 



The mosquito netting was loosely attached to the cage, so that the 

 shock to a fly in striking against it was minimized. 



One or two captured females of Tahanus corax oviposited in these 

 cages, the process in one instance taking nearly an hour, between 

 3 and 4 p.m. Many egg masses of this species were also obtained in 

 the bush, always on reeds or grasses overhanging mud. While the 

 female is ovipositing she is not easily disturbed, as in the case of Ta- 

 hanus higultatus (King), and on one occasion one of Neave's collec- 

 tors brought him the reed, fly and all, from more than a mile distant 

 without disturbing the female. The egg mass with its cement cov- 

 ering is pure white when first laid, becoming dark gray as it hardens. 

 The cement which covers these egg masses must be, according to 

 Neave, water-proof and insoluble, as some individuals from them 

 succeeded in hatching even though the egg mass had been kept in 

 70 per cent alcohol for two days. 



The egg masses of Tahanus corax are of the usual tabanid type, all 

 the individual spindle-shaped eggs being laid with their long axes 

 in the same direction. In the cases observed hatching took place 

 about the fifth day, but this would be likely to be lengthened or 

 shortened in some cases, according to the temperature. The process 

 of hatching takes place very suddenly. The egg mass splits in the 

 midline, following the long axis, and the small larvae emerge almost 

 simultaneously, forming a large quasi-viscous drop which falls bodily 

 from the reeds, etc., into the water or mud below. 



A number of newly hatched larvae were obtained from collected 

 egg masses, generally found on reeds overhanging swampy ground. 

 The young larvse grow very slowly at first. Neave figures the 

 syphon and anal segment of one of these young larvae. The figure 

 (Plate 10, Fig. 120) shows the pecuHar Graber's organ, somewhat 

 tongue-shaped or triangular, and, according to Neave, attached by 

 fine strands of muscle from each of the three corners, apparently to 

 the body wall. It lies above the gut immediately below the dorsal 

 integument and seems to be capable of motion independent of the 

 general body movements. The organ contains a number of pairs of 

 small black pyriform bodies. 



Neave obtained the larvae of Tahanus corax in considerable num- 

 bers. Adult specmiens are large, from 40 to 45 mm. in length, and 



