140 



visible when they have quitted the larval head. These bosses are separated 

 from the head by a narrow smooth surface ; a small lateral tubercle intervenes 

 between them and a lateral or ventral process. A similar lateral or ventral pro- 

 cess belongs to each of the two following segments ; and I may describe them 

 together (Figs. 14 and 15) ; each extends laterally, is conical and somewhat 

 pointed, and is divided by constrictions into three portions. As they are also 

 distinctly anterior to the lateral tubercles proper, I think they must be called 

 legs, although they possess no corneous plates or claws, and are in fact of the 

 same pellucid structure as the other tubercles ; they appear to assist, passively 

 rather than actively, in holding the wasp-grub. The third and fourth segments 

 have each two large dorsal bosses or tubercles, with two smaller ones beneath 

 each, and an indication of a lateral tubercle. The fifth and sixth segments have 

 similar but less marked dorsal tubercles. All these segments are much nar- 

 rowed ventrally. The sixth with the following segments form the longitudinal 

 portion of the body of the larva ; they are much compressed from before back- 

 wards, this being most marked in front. Though nearly plain at the actual 

 dorsal ventral and lateral lines, the segments are deeply incised in front and 

 sometimes behind, though this is not marked behind in a plump larva': these 

 segments have an indication of dorsal tubercles. The twelfth segment is 

 smaller than the others, and is very narrow in front, as the last segments 

 curve forwards and upwards ; the thirteenth, still smaller, appears to be 

 divided into two, and there is, in addition, a very distinct rounded anal tubercle. 

 The dorsal vessel is a straight hiatus between the masses of white fat, and, 

 though it is not so, looks not unlike a groove ; and in a larva preserved in 

 spirit the skin might readily shrink into it and actually make it one. Except 

 the tubercles, dorsal vessel, and some of the intervals between the segments, 

 the body is full of white fat disposed in small rounded convoluted masses. 

 The spiracles are eight in number' on each side: the first is near the anterior 

 border of the third segment, about half way between the dorsal and leg 

 tubercles ; the second is just above and in front of the lateral tubercle of the 

 fifth segment ; the others are in the six following segments, in a little hollow 

 behind the lateral projection, and near the anterior patt of the segment. The 

 twelfth segment has a similar hollow, but no spiracle. In the third and fourth 

 segments there are seen very early a pair of tracheal on the side of each, which 

 indicate the wings and elytra already forming. 



When it emerges, Rhipiphorus is nearly as large as tbe wasp whose place 

 it has usurped, although not quite, and, like the wasp ftself, has fed on a mass 

 of food but little exceediug its own bulk : curiously illustrating this is the long 

 known fact that the Rhipiphori that emerge from queen cells much exceed in 

 size those that emerge from the cells of the workers, without reference to the 

 sexes of the beetles so emerging, — males as well as females emerging from the 

 queen cells. 



The point which most requires investigation is the place and manner 

 of oviposition of Rhipiphorus. As the young larva is active, it-is by no means 



