72 



THE AMERICAN ENTOMOLOGIST. 



ping an egg along with a minute drop of poison 

 into eacli puncture. Until the following spring 

 these eggs always lie dormant, as in many other 

 such cases; for Dr. Fitch is altogether wrong in 

 asserting that there are two distinct broods of 

 Wool-sower Gall-flies every year, generating 

 two distinct sets of galls.* Wo have examined 

 hundreds of these galls at all seasons of the 

 year; and never yet did we find one at a later 

 period than the end of July, that was not bored 

 up, empty and untenanted. In fact, it is not 

 often that they remain on the twigs through the 

 winter ; for when ripe they are attached so very 

 slightly to the twig upon which they grow, that 

 they can readily be slipped up and down like 

 the beads of a rosary, and the least lateral jerk 

 displaces them entirely. 



The Leafy Oak-sail. 



( Qiiercus fnniosa ? Biissett. )t 



This gall, the immature stage of which we 



herewith present a drawing (Fig. 4G a), has 



[Fig. 



eUjlor— Green . 



for many years been a puzzle to us; and even 

 now its history is not yet completely developed, 



S"iV .-M^Trnt" R-'/x.r/s, \.'\. II, r:;l-. 



-iciwill-oiit ol II Thili.st. that 1 

 iistances, is to m'ESS ttiut lie is sa 

 lid meauing auother tbiug. Uut as we are i 



though we have examined hundreds of speci- 

 mens of it. When mature it often attains a 

 diameter of two and a quarter inches, and the 

 modified leaves of which it is composed are then 

 much longer and jiroportionally much wider 

 than they are at first, so that instead of being 

 what the botanists term "lanceolate" they be- 

 come " oval," with their tips usually acute, and 

 occasionally with a more or less well-developed 

 acute tooth projecting from one side of the leaf. 

 Just as, in the case of the Pine-cone Willow- 

 gall,* although the leaves of the willow upon 

 which it grows are always sharply toothed upon 

 their edges, those of (he gall itself are never 

 toothed at all, so in the case of this Leafy Oak- 

 gall the leaves of which it is composed are 

 never roundly many-lobed, as are those of the 

 different oaks upon which it occurs. They are 

 further anomalous by very generally lacking 

 the rib vein found in the normal leaves of all 

 oaks. So singular very frequently is the influ- 

 ence of the gall-making insect upon the vegeta- 

 tion of the plant which it attacks ! 



In a mature Leafy Oak-gall which we now 

 have before us, some of the leaves of which it is 

 composed are nearly one and a half inch long 

 by half an inch wide; and those that are smaller 

 are proportioned nearly in the same way. The 

 gall is developed after the summer growth of 

 the tree is completed; and the axillary bud, 

 which otherwise would not burst until the 

 spring following, is forced, by the punctures of 

 the Gall-fly, to develop prematurely in the re- 

 markable manner illustrated above. Such galls 

 as are of small size contain but a single cell 

 (Fig. 40 6), which though its shell is thin is tol- 

 erably hard and diflScult to crush — but the larger 

 ones often cover three, four or five such cells; 

 inside this cell reposes the larva, as shown in 

 the figure, and the characters of the lai-va indi- 

 cate it unmistakably to be that of some Gall-fly 

 or other, although it has not as yet been reared 

 by any one to the perfect fly state. By parting 

 the leaves of the gall, the tip of the greenish 

 white cell may be seen imbedded among them; 

 and singular to relate, about the middle of the 

 autumn, when the gall becomes mature, the 

 cells are gradually disengaged from their leafy 

 matrix and drop to the ground, where no doubt 

 the larva will pass the winter more agreeably 

 among the masses of dead leaves which accu- 

 mulate in such situations, than it would do if 

 it were exposed aloft to the stormy blasts and the 

 cold driving sleets of the dead season of the 

 year. In all probability the future Gall-fly bursts 

 forth from its snug retreat some time in the fol- 



• See Amkk. Ent. I, p. 105, Fig. 



