HYMENOPTERA SAW-FLIES, ETC. 165 



Aculeata, according as the ovipositor of the female is modified into 

 a "boring instrument" or a "sting." But this distinction is often 

 hard to maintain, and also appertains only to one sex, which is un- 

 satisfactory. Another division — viz., into Sessiliventria and Petiolata, 

 according as the abdomen is attached to the thorax over its whole 

 width, or at one point only by a narrow and stalk-like first segment — 

 is not open to the above objections, and is here adopted. 



The Sessiliventria are also called by English writers " Saw-flies," 

 and by German " Blattvvespen " {i.e., leaf-wasps). Such Hymenoptera 

 as are of special interest to the forest entomologist belong mostly to 

 this division, and I have therefore thought it worth while to call 

 attention to the further classifications which have been introduced 

 into it by specialists, and to indicate some of the writings on the sub- 

 ject which are likely to assist such students as desire to master it to 

 a greater or less extent. 



The most useful complete works dealing with the saw-flies of large 

 areas as a whole are — 



Kriechbaumer's collection of King's writings on Blattwespen (Ber- 

 lin, 1884); Hartig's 'Families of Leaf and Wood Wasps' (Berlin, 

 1860); Thomson's 'Hymenoptera Scandinaviae,' vol. i. (Lund, 1871); 

 Andre's 'Species,' vol. i. (Beaune, 1879); and (for British genera 

 and species) Cameron's Monograph, e^c. All these works, however, 

 are beginning to get old ; and since their appearance much new 

 light has been thrown upon the group by a very able and original 

 German naturalist (Pastor F, W. Konow), who has published a vast 

 number of short articles and revisions of particular genera, and is now 

 issuing a monograph (on the very largest scale) of the saw-flies of the 

 whole world. Consequently several names of species, and even genera, 

 hitherto in common use are destined to be superseded before long, 

 and some may be said to be already out of date. A series of papers 

 by Mr Morice now appearing in 'The Entomologist's Monthly Maga- 

 zine,' entitled " Help-notes," &c., has for one of its chief objects to 

 inform English students of the alterations in the British list (at pres- 

 ent resting mainly on Cameron's work), which seem to be required in 

 consequence of Konow's researches hitherto ; and also to facilitate the 

 study of the subject, by fresh tabulations of generic and specific char- 

 acters, which the writer hopes will generally suffice to guide collectors 

 to a correct determination of the specimens taken by them. 



In view, therefore, of the importance of Mor ice's " Help-notes," I 



