372 



Observations on the Turnip Saw- Fly. 



each side, the scutel and the tip of the hinder scutel of the same colour. 

 Abdomen, or body, short, somewhat cylindrical in the male ; the apes 

 rounded (12) ; much broader and more depressed in the female (IS), 

 the apex pointed, wiih an ovipositor partly concealed in a slit beneath 

 {t), and porrected between two rigid spoon-shaped lobes or valves (16), 

 hollow inside, but convex and very hairy outside ; they are ochreous, 

 with a black patch at their apex (w), and enclose four fine lancets, the 

 lower or outside ones (17) being the longest, and the upper and more 

 inner ones being a little shorter (18) ; they are all thickened at the back, 

 the sides have twelve or fourteen ridges, and the thinner margins are 

 slightly serrated at the points, which seem to be most acute in the inner 

 pair : there are also two united blackish spots at the base of the body, 

 and a black dot on each side. Wings, four, ample, all reticulated, 

 iridescent, yellowish at the base, the thickened costal margin and the 

 callous stigma pitchy ; the superior wings are the longest, with two 

 marginal, four sub-marginal, and various other cells, formed by reticu- 

 lated nervures. Legs six, rather short (19) ; thighs stoutish (v) ; 

 shanks or tibice clavate, all hairy, with a pair of acute unequal spurs at 

 the apex, and tipped with black (w) ; iarsi or feet rather long, whitish, 

 and five-jointed (x), the four first joints having little appendages or 

 suckers beneath (y) ; tips of all the joints black, the apical one entirely 

 black, as well as the two acute claws with which this joint is furnished ; 

 there are also attached to them two little suckers, called pul.villi {z}. 



The males are hatched first, and appear a few days previously 

 to the females^ which sex is not only larger, but, the size of her 

 body being" greater, she looks of a brighter orange colour, and 

 may be thus detected even when upon the wing. It generally 

 happens that the female saw-flies are much less abundant than 

 the other sex, and this is believed to be the case with the kind of 

 saw-fly w e are now describing, the males being as six to one when 

 they have been bred ; but it has been exactly the reverse in those 

 I have caught in the fields, for out of fifteen specimens there were 

 only three males. Both sexes can be equally active, but on being 

 touched they feign death ; closing their wings and contracting 

 their legs and horns, they look like shrouded bodies ; they are 

 also torpid in moist and cloudy weather, but very alert when the 

 sun shines, the males playing with each other or sporting with 

 their mates. They use their wings much more than their legs ; 

 and when a female is observed walking about a leaf, it is for 

 the purpose of depositing her eggs. They are frequently found 

 on cruciferous and umbelliferous flowers, upon the pollen of 

 which the flies subsist ; and Mr. Marshall says they are partial 

 to honey, and will sip the sap which oozes from the broken end 

 of a turnip-leaf.* The fceces are cream-coloured, and of a similar 



* Other species, as Tenthredo scrophularicB, T. viridis, &c., are not satis- 

 fied with this licjht food, but live upon soft-bodied insects, and will even 

 attack the Telephori (Curtis's Guide Gen. 317, and Brit. Ent.. pi. 215); so 

 that the larvce are phy tivorous, whilst the imagos are insectivorous ! 



