Rev. F. T). Morice's Notes on Australian Sawflies. 315 



in the form of the last dorsal segment. This is constricted 

 laterally and drawn out into a kind of spine which over- 

 hangs the base of the terebra, and is often jagged at the 

 sides in a manner which suggests that it may play some part 

 in the operations of the latter. (In the Oryssidae, however, 

 the last dorsal segment is simple, but in these the terebra, 

 though actually longer than the abdomen, is so slender and 

 elastic, that it can be bent back at its base, and packed 

 away out of sight in the abdomen itself. This Family, as 

 several authors have remarked, seems to be a link between 

 the Chalastogastra and other Hymenopterous groups, 

 especially, I would suggest, the Cynipidae.) 



The ovipositions of the Tenthredinidae are made quite 

 otherwise. Here the eggs are to be so placed that the free- 

 moving larvae may pass at once after hatching to the 

 leaves which will form their food. There would be no gain, 

 but the contrary, if the eggs should be sunk any more 

 deeply into the food-plant than suffices to keep them in 

 position till the larvae emerge from them. They are 

 deposited accordingly, never at any great depth, in a sort 

 of slit or pouch formed by the terebra of the $ parent 

 between the transparent cuticle of a leaf (or stem) and the 

 tissues underlying it. The terebra best adapted for cutting- 

 out such a receptacle need not be particularly long, and 

 extreme slendemess would be actually undesirable. As a 

 matter of fact, the form of the pouch, and the manner of 

 its formation varies considerably in different cases, and 

 though the " saws " of all Tenthredinidae have a certain 

 family-likeness they differ exceedingly in details for reasons 

 which have yet to be discovered. But, at any rate, they 

 are always much broader and thicker in proportion to 

 their length than those of any Siricid. armed with many 

 more denticulations, and altogether departing much mote 

 from what seems likely to have been the primitive type of 

 an ovipositor. They seldom extend beyond the apex of 

 the abdomen, and are never too long to be completely 

 sheathed, when not in use, within the modified last ventral 

 segments. The dorsal segments seem to be little if at all 

 affected as to their shape and size by their vicinity to the 

 ovipositor. Occasionally they are slightly compressed 

 laterally in the anal direction, but never so as to form an 

 actual spike, and they may usually be described as simple. 

 We have now seen (1) that to a certain extent the different 

 manner of oviposition in the two groups seems to be actually 



