38 THE EARLY STAGES OF TABANIDiE 



shaped cyst with a slight constriction in its wider part; its pointed 

 end is turned hindwards. Inside this cyst are found, in the cases 

 examined, several pairs of black rounded chitinous pedunculate 

 bodies; each pair of these bodies is in turn enclosed in a special chit- 

 inous capsule filled with liquid. The attachment of the muscles and 

 nerves to this cyst are described in detail. The cyst is continued, 

 at its pointed end, into a contorted canal which opens in the deepest 

 place of the infolding between the eighth and ninth abdominal seg- 

 ments (Plate 10, Fig. 115). The canal and the cyst are covered in- 

 side with chitin and completely surrounded by the hypoderma, so as 

 to warrant the conclusion that the whole organ must be an invagina- 

 tion of the integument, as Graber had supposed, though he was 

 unable to see the opening of the terminal tube. 



According to Graber, the first cyst contains in its interior four pairs 

 of pedunculate chitinized bodies; the first pair being in a closed cap- 

 sule, the second inside another capsule, the latter not completely 

 closed posteriorly, and finally the remaining two pairs contained in a 

 common sac, open posteriorly. 



Paoli states that the number of pedunculate bodies is not limited 

 to four pairs, but varies according to the age of the larva. Graber also 

 said (in his later work), that in the young larva there is only one 

 pair of such pedunculate bodies, and that the second pair is formed 

 later. Henneguy, who examined a newly hatched larva, found only 

 one pair. 



Paoli found four pairs in larvae about 1 cm. in length, but in speci- 

 mens of larvae in later stages of development he always found a greater 

 number, up to seven pairs in larvae of almost 3 cm. in length. Each 

 pair was found enclosed in a capsule which remains more or less open 

 posteriorly, but which is always present; the largest of them, that is, 

 that which is located anteriorly, has the thickest walls and is formed 

 last, and it is only this one which is really living and in function, 

 while all the others are dead and have no function whatever, differing 

 little from one another, especially the capsules enclosing the smallest; 

 namely, the oldest pairs of pedunculate bodies. 



Each of the pedunculate bodies has the shape of a slightly elliptic 

 ball, their surface being smooth or sometimes rugose. They are 

 strongly chitinized, black, frail, and breakable, as under pressure 



