THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY 



No. 70. APRIL 1843. 



XXXV. — Observations on the Habits of a Tenthredo or 

 Saw-fly, By Pierre Huber*. 



[With a Plate.] 



The insect which is the subject of this memoir is, I conclude, 

 somewhat rare in our country [Geneva], as I have not yet ob- 

 served it except in the larva state ; and these larvae are so un- 

 common, that in looking diligently for them, I have scarcely 

 found more than one or two every year. My design is to make 

 known the first period of its history, looking for the time when 

 more favourable circumstances may enable me to complete it. 

 I especially regret my inability to give the description of the 

 perfect insect ; but, as we know with respect to a great num- 

 ber of insects, all the philosophic interest attaches to the hi- 

 story of the larvae. It is these indeed which most frequently 

 exhibit to our sight that industry which so justly excites our 

 admiration. 



This insect belongs to that division of the Saw-flies {Tent lire- 

 dinidce),the larvae of which, not furnished with membranous feet 

 (prolegs), have only six coriaceous feet belonging to the thorax, 

 and whose hind part or abdomen is armed laterally with two 

 hard and horny processes which diverge from one another 

 nearly in a straight line. These very prominent processes, I 

 believe, are attached to the last ring but one. The last ring 

 did not appear to have organs like the anal prolegs of cater- 

 pillars ; it is, on the contrary, of a coriaceous and solid sub- 

 stance, variegated with a brown colour above ; it terminates in 

 an oval margin, and opens upwards in order to serve as a 

 passage for the rejectamenta of the insect ; but in some cases 

 it also performs the office of a foot. The head is wholly coria- 

 ceous, its eyes are very distinct and prominent; it is furnished 

 with strong and rather short jaws, with two antennae placed 

 near the eyes, and with two or three pairs of palpi, the length 

 of which exceeds that of the jaws, and which serve the purpose 



* From the Memoires de la Socie'te de Physique et d'Histoire Naturelle 

 de Geneve, torn. ix. part 2, 1842. 



Ann. $ Mag. N. Hist, Vol.xi. R 



