THE AMERICAN ENTOMOLOGIST. 



49 



therefore he was philosophically a far more in- 

 teresting object than the poet Pope, who 

 weiglied only about a hundred pounds! As if 

 a sunflower was more deserving of our admira- 

 tion than an orange blossom ! As if we ought 

 to make a pet of a vulture rather than of a 

 mocking-bird! 



The Willow-et'iT (fall, 



{Salkh otum, AValsh). 



On examining particular bushes of the Heart- 

 leaved Willow in the middle of the summer, 

 and especially such as seem to be in a diseased 

 and stunted condition, it will be noticed that 

 many of the twigs have one or more round or 

 oval swellings, from one-third to one-half an 

 inch in length, projecting from their sides, such 

 as are shown in Figure 31. If we cut into these 

 swellings in the summer, their internal sub- 

 stance will be found to be whitish and flesliy 

 like that of an apple; but [Fig. 31 ] 



by the autumn the apple- 

 like pulp is converted into 

 a reddish-brown sponge 

 with many transverse tis- 

 surcs at right angles to the 

 axis of the twig. By dis- 

 secting down at any time 

 to the original surface of 

 the twig, a longitudinal 

 slit will be discovered, 

 about one-lifth of an inch 

 long, manifestly produced 

 by the saws of the female 

 Sawfly that generates this 

 gall. This species of Saw- ^ 

 fly comes out in the mid- " '°W\v""c:iies.' ''' ''' 

 die of the preceding April, and produces 

 the future gall by depositing in the slit which 

 she has cut with her saws a single egg, ac- 

 companied by a drop of the peculiar poison 

 secreted by each species of gall-producing 

 Saw-flies. If one of these swellings, known 

 as the Willow-egg gall, is cut into about the last 

 of August, the larva that has hatched out from 

 the egg will often be found imbedded in the slit, 

 and already more thau one-tenth of an inch 

 long, of a pale-yellowish color, with three pairs 

 of true legs and seven pairs of pro-legs, and a 

 very pale dusky head having the usual lateral 

 dark eye-spots. At this date, and even as late 

 as the first week in the succeeding March, many 

 full-sized galls will be found to be still solid 

 and uneaten by any larva, no doubt from the 

 egg having failed to hatch out; thus proving 

 that it is the drop of poison deposited along 



^-'^v^ww-ri'O'V 



with the egg by the mother Sawfly, and not the 

 action of the jaws of the young larva produced 

 from the egg, that generates the gall. About 

 the middle or latter end of the April of the fol- 

 lowing year after the formation of the gall, the ; 

 perfect Fly, after passing through the usual i 

 pupal stage, bursts forth from the interior, which ' 

 by this time has been reduced to an irregular 

 hollow filled with the larval excrement or 

 " frass," as it is technically termed. This fly 

 belongs neither to the genus {Nematus) which 

 has four submarginal cells (Fig. 7, page 16), 

 nor to the genus (^PrisUphora) which has three 

 submarginal cells with the cell next the body 

 very long (Fig. 11, page 20), but to another 

 genus {JSuura) which has three submarginal 

 cells with the cell next but one to the body very 

 long. But as we have dwelt at considerable 

 length upon this somewhat dry subject on page 

 I'O of this volume, we need not repeat here what 

 we have already said. AVilh the exception of 

 this curious ditference in the structure of the 

 wing-veins, the figure of the Native Currant 

 Worm Fly, given on j)age 20, will represent 

 with sujficient accuracy the Willow-egg Sawfly 

 (Euiira S. ovum, Walsh), except that the gen- 

 eral color of the latter is honey-yellow in the 

 female and greenish white in the male, instead 

 of black in both sexes, and except that the size 

 is a little smaller and the bodv much less robust. 



The AVillow-l)iul Gall. 



[Salicis gemmaj "Walsh) , 

 For a long time, in the course of the winter 

 and early in the spring, we had noticed here and 

 there on particular twigs of the Humble Willow 

 {Salix humills) — a dwarf sjiecies which grows 

 on the driest uplands — particular buds preter- 

 naturally enlarged in the manner shown in 

 Figure 32 at b 6, buds of the natural size being- 

 represented at a a a. On examining into such 

 enlarged buds, we found most of them reduced 

 to a mere hollow shell, with a round pin-hole in 

 it, through which some lai-va must have made 

 its exit. A few such buds, however, which 

 had evidently not been depredated on by any 

 insect, instead of being filled by the normal 

 downy embryo leaves, contained a homogene- 

 ous grass-green fleshy matter. Here then was 

 a riddle to be solved! What made these buds 

 swell so prodigiously? What converted the 

 organized downy leaves into a mass of green 

 pulp showing no signs of any organization? 

 What insect had disappeared through the pin- 

 hole, probably in order to transform under the 

 surface of the earth? For several years the 



