REPORT OF THE ENTOMOLOGIST. 



335 



our departure for Europe, found, at that date, but a single female, 

 sitting on a braneh of about 5 n,m in diameter, and just in the act of cut- 

 ting one of the incisures referred to above. The insect worked its 

 mandibles in a very slow and deliberate manner, and made but little 

 headway in cutting during the three or four minutes he watched its 

 workings. Upon examination the twig was found to contain three 

 such incisures, each reaching more than half way around. 



THE EGGS AND MODE OF OVIPOSITION. 



Whether or not the cutting of the tips is made for feeding purposes, 

 it is evident that it has nothing to do with ovi position, as no trace of 

 the eggs could be found either on the dead part of the twig or in the 

 living portion just beneath. The eggs are deposited between the epi- 

 dermis and parenchyma of the leaf. When looking over the plants 

 from above, the place of ovipositiou is hardly i>erceptible, appearing as 

 a very slight, blister-like swelling, accompanied on one side by a faint 

 ferruginous line, but otherwise not differing in color from the rest of the 

 leaf. On the underside, however, these blisters were very plainly visible, 

 being much paler than the rest of the leaf, and having, in the more 

 developed condition, a reddish tinge. These blisters closely resemble 

 those of other saw-flies, which insert their eggs in leaves and are 

 usually nearly circular in outline (sometimes nearly oval), and distinctly 

 elevated above the general surface of the leaf, though otherwise quite 

 flat. They are always on the face of the leaf, usually nearer to the outer 

 margin than to the midrib, never on or near the midrib and rarely 

 extending across one of the side ribs. Their number varies from 

 one to nine or more on a single leaf. Where there are several they are 

 generally situated in a longitudinal row, the individual blisters being 

 then always separated by the intervening side-ribs. 'Sometimes two 

 rows of these blisters are found on the same leaf. The place of inser- 

 tion of the ovipositor is always plainly visible, as a nearly straight slit 

 (usually closed) of ferruginous or brownish color at or near that edge 

 of the blister which is nearest to the margin of the leaf, thus indicating 

 that, while ovipositing, the female fly grasps the edge of the leaf with 

 her fore legs. (PI. V, Fig. 1, a.) 



Leaves infested with eggs, although not rare, were by no means so 

 abundant as should have been expected from the extent of the injury 

 inflicted by the imagos. A great many plants (and among them many 

 with their tops cut off) were not infested, while occasionally a plant 

 could be found with four or five infested leaves, mostly about the 

 middle or near the top of the plant. 



The egg, when about ready to hatch, is oblong-oval, somewhat flat- 

 tened, and with its shell so thin and pliable that it not only loses its 

 regular shape by the*slighest pressure, but even by the position or 

 movements of the embryo larva within. The shell is perfectly hyaline, 

 with no visible sculpture besides some fine, irregular, and variable 

 wrinkles. Its surface is very sticky. At an earlier stage the egg is 

 elongate and nearly cylindrical. Through the whitish epidermis of the 

 blister the shape of the egg is always readily perceptible as a trans- 

 verse (i. e., parallel or nearly parallel to the margin of the leaf) object 

 ox a decided green color. (PI. V, Fig. 1, c.) 



The young larva, after hatching, remains for some time within the 

 blister, but finally leaves it through an irregular slit at the middle of the 

 epidermis. Its color is bluish-gray. (PI. V, Fig. 1, d.) 



