THE LARCH WORM. 885 



The eggs had all hatched by June 23 to 28 ; few were to be found at 

 Brunswick, although the incisions made by the female were commonly 

 observed. The female saw-fly makes about a dozen incisions in the ter- 

 minal young, fresh, green shoot, sometimes in one of the side shoots 

 next to the terminal one ; judging by the shape of the hole, the eggs 

 are of the shape described by Ratzeburg, i. e,, oval cylindrical and 

 about 1.5'""> in length. The eggs are placed in two rows, alternating, 

 not exactly parallel, one being placed a little in advance of the other. 

 The eggs are inserted at the base of the fresh, soft, young, partly-devel- 

 oped leaves of the new shoot, which is usuall}^ by June 20-30, only 

 about an inch or an inch and a half in length. The presence of the 

 eggs causes a deformation of the shoot, which curls over, the incisions 

 being in all cases observed on one (the inner) side of the shoot. In 

 many cases a last year's shoot was observed with the scars of the 

 incisions on the concavity of the shoot. That the incisions were made 

 by the saw-fly was proved by finding a freshly hatched but dead larva 

 in one of the holes. Sometimes one or two of the leaves die in conse- 

 quence of the wounds made at their base. 



After the foregoing lines were written we fortunately observed a 

 female in confinement, June 29, while engaged in the process of oviposit- 

 ing ; we should judge that the operation of sawing the slit and depositing 

 the egg required not less than five minutes, and perhaps not much more 

 than that length of time. The fly had been evidently at work for some 

 time previous, as a number of eggs- had been laid along the shoot; she 

 had begun at the farther end and worked down to the base of the new, 

 fresh, green shoot. She stood head downward while engaged in making 

 the puncture, and was not disturbed by our removing the larch twig 

 from the glass jar and holding it in our hand while watching the move- 

 ments of the ovipositor under a Tolles triplet. The two sets of serrated 

 blades of the ovipositor were thrust obliquely into the shoot by a saw- 

 ing movement; the lower set of blades was most active, sliding in and 

 out alternately, the general motion being like that of a hand saw. After 

 the incision is sufliciently deep, the egf^ evidently passes through the 

 inner blades of the ovipositor, forced out of the oviduct by an evident 

 expulsive movement of the muscles at the base of the ovipositor. The 

 slit or opening of the incision after the egg has passed into it is quite 

 narrow and about If'""' in length. While engaged in the process the 

 antennae are motionless, but immediately after the ovipositor is with- 

 drawn they begin to vibrate actively, the insect being then in search 

 of a site for a fresh incision. 



After making the foregoing observations we found at Phillips, Me., 

 July 1, and Errol, N. H., July 4, numerous twigs containing eggs, and 

 the flies were also observed upon the trees ovipositing. Although the 

 slit is at first closed, as soon as the embryo increases in size the twigs 

 swell where they have been incised by the ovipositor, and the slits en- 

 large and gape more or less, becoming much larger and more conspicuous 



