GENUS SIREX. 131 



labium is broadly incised. The maxillae are united at 

 the base. The maxilla proper is composed of one long 

 narrow lobe, rounded at the apex and covered with 

 long hairs. At the base laterally is a short thick 

 palpus. From where this issues from the maxilla 

 there is a short projection, but whether it represents a 

 joint or only a slight dilatation of the maxilla I cannot 

 say, but in some species it has every appearance of 

 being a joint. The cardos are united by a stout mem- 

 brane of the same colour and consistency as them- 

 selves ; they are rounder, contracted at base, and bear 

 on the apex some long hairs. 



The radial and cubital nervures seldom reach to the 

 apex of the wings, so that thus the second radial and 

 four cubital and outer discoidal cellules are continuous. 

 The first radial cellule is much shorter than second. 

 Of the cubital cellules the first is minute, the second 

 as long as the third and fourth together. Often the 

 transverse basal nervure is joined to the first transverse 

 cubital. Stigma longish, linear. There are two middle 

 cellules in posterior wings. 



The abdomen has eight segments. On the back all 

 are fully developed; the basal is longer than any of 

 the five following, which are of nearly equal length ; 

 the seventh is larger; the eighth is still larger, and 

 terminates in a long hollow spine, the sides of which 

 bear irregular, short, tubercle-like teeth. On the ven- 

 tral surface the basal segment is fully as large as its 

 upper portion, and it does not project so far to the 

 base, but is pushed more to the apex; the second, 

 third, and fourth are smaller than the upper divisions ; 

 the fifth is smaller and much contracted in the middle ; 

 the sixth projects in the middle, so that it is more 

 than double the length of the fifth, but it is contracted 

 at the sides. At the apex the lower and upper divi- 

 sions (the hypopygium and epipygium) are united. 

 Beneath in the middle there is a long slit in which the 

 ovipositor lies. Above (except at the apex) it is open, 

 this part being covered by the sixth and seventh seg- 



