Euura orbitalis

Euura salicisdesmodioides

Rabdophaga salicisstrobiliscus

Euura salicisnodus

Rabdophaga salicisgnaphalioides

Rabdophaga saliciscoryloides

Rabdophaga rigidae

Iteomyia salicisverruca

Eriophyes semen

Aculops aenigma

Euura salicisovum

Euura salicisovulum

Euura salicispomum

Euura salicispisum

Lasioptera solidaginis

Euura salicis gemma, n. sp.

On Salix humilis

The lateral bud of a twig, enlarged so as to be twice or thrice as long wide and thick as the natural bud before it begins to expand in the spring, its external surface otherwise en- tirely unchanged both in texture and color. Internally, instead of the normal downy embryo leaves, it contains early in the autumn a homogeneous, grass- green, fleshy matter, which is afterwards gradually consumed by the larva, leaving nothing at last but a mere shell, as thin as paper, and partly filled with excrement. Sometimes, from the egg failing to hatch out, this green fleshy matter remains unaltered till the spring. The gall is monothalamous, sometimes one only on a twig, sometimes two or three or more at irregular intervals, very rarely as many as 3 or 4 formed out of 3 or 4 consecutive buds. Common and not local. Described from 34 specimens. Length .17 — .36 inch; breadth .10 — .17 inch. Analogous to the Cecidomyidous gall 8. cornu Walsh, but very differ- ent in its general aj^earance and in its internal structure. 

Nesmatus salicis desmodioides, n. sp.

On Salix humilis

A smooth, flattish, fleshy, sessile, yellowish-green, monothalamous gall of a semicircular outline, the chord of the semicircle adjoining the midrib of a leaf; its general shape like the seed of a Desmodium, or like the so-called "quarter" of an orange, the thin inside edge of the "quarter" closely hugging the midrib of the leaf, and the robust outer surface not biangulated but rounded off. No rosy cheek. The volume of the gall is generally about equally divided between the upper and lower sides of the leaf, but sometimes the lower portion is rather the larger. Usually there is but a single gall on a single leaf, but occasionally there are two of them either on the same side or on opposite sides of the midrib. One leaf was noticed with as many as three of these galls upon it. Length .23 — .50 inch; 131 specimens. The above is the appearance of the mature gall July 30; but on May 17 it is already nearly full-sized, and then many of them have a rosy cheek like the normal S.pomum. Abundant and not local. Distinct from S. pomum by its very different shape, and by its never having any rosy cheek when mature, and by the very distinct species of willow on which it occurs. 

Cecidomyia salicis strobiliscus Walsh

I described this gall from a single dried specimen found by Mr. Bebb on Salix rostrata [bebbiana] in North Illinois. I have since found very numerous specimens of what for the present I regard as the same gall on S. discolor near Rock Island, IL. Of 23 gathered March 23d one was undistinguishable from the S. rostrata gall; the rest had the tips of the external leaves (except at the tip of the gall) not angulated, but more or less rounded with a subobsolete midrib outside which terminated in a minute tooth or beak. In other respects they did not differ, and especially in the veins on the inside of the leaves being obsolete or subobsolete. The general outline of this gall was ovate lanceolate, rarely ovate ; length — rejecting one stunted specimen, which however contained a larva — 1.05 — 1.G5 inch, diameter .57 — .72 inch. The stunted specimen was not porrect, but deflected at an angle with the axis of the twig, and I subsequently found a few others varying in the same way. In one gall I met with 2 or 3 of the same Orchelimum eggs which occur so copiously in S. strobiloides 0. S., and May 26th I bred several Orchelimum larvae from these galls. 

Euura salicis nodus, n. sp.

On S. longifolia [interior]

A mere gradual enlargement of a twig from 1/4 more than its norma] diameter up to twice its normal diameter, almost always without any abnormal roughness on the external bark, and always not confined to one side only of the twig. General color that of the twig. When cut into, Aug. 28, the interior of each gall is found to be pithy, and to contain 1 — 3 larvae in separate cells. Frequently, on a piece of a twig 6 inches long, 2, 3 or 4 of these galls are placed at irregular intervals. No appearance internally of any transverse plates or transverse fibres as in S. ovum and S. ovulum. Length .75 — 1.50 inch; diameter .10 — .2.5 inch. Described from 31 affected twigs. Abundant but very local. Very like the Cecidomyidous gall S. nodulus on the same willow, but is much larger, is polythalamous instead of monothalamous, and occurs near Rock Island, IL., in quite a different locality. Analogous willow-galls are made in Europe, not by a Euura, but by several small species of Nematus.

S gnaphalioides

I found a single specimen on a bush of S. discolor growing among numerous S. humilis, on which last willow alone this gall had previously occurred. A very similar gall, but differing in the tips of the leaves not being beaked, was gathered on S. Candida by Dr. Geo. Vasey, in Illinois. I have 8 dried specimens of it from Mr. Bebb. 

S coryloides

I have since fouod two additional specimens in a different locality, and as before on S. discolor. Thus, in addition to the occurrence of two very distinct but closely allied bud-galls on the same species of Willow, S. humilis, viz : .S. rhodoides and S. gnaphalioides, we find two very distinct but closely allied bud-galls on the same species of Willow, S. discolor, viz : S. strobiliscus and S. coryloides.

S siliqua 

Besides the single one found on S. discolor, I have since found about a dozen others on that Willow, and received through Mr. Bebb over a dozen gathered on that Willow in New Hampshire by the Rev. W. J. Blake. They can only be distinguished from galls found on S. humilis by their uniformly larger size, which may be due to the rank growth of this species of Willow. Mr. Blake also sent me many specimens of this same gall gathered on S. rostrata [bebbiana] in New Hampshire, which were about the same size as those found on S. cordata ; and I have a single dried specimen gathered in Illinois on S. petiolaris by Mr. Bebb. Thus we have what seems to be the same gall growing on six different Willows. S. humilis, S. discolor, S. rostrata [bebbiana], S. cordata, (=S. rigida) [eriocephala], S. petiolaris. and according to Dr. Fitch on S. lucida. I said that the terminal beak of this gall is never recurved in specimens growing on S. humilis; but in 1865 I found one such gall on S. humilis. In those growing on S. rostra ta this is particularly common. It is singular that some galls should be thus found on many Willows, and others apparently be restricted to one species; but the same phenomenon occurs in Cynipidae. In one of the public squares in Rock Island, 111., there grow 30 or 40 trees of the exotic S. alba, and interspersed among them many bushes of the indigenous S. longifolia covered with their peculiar gall, S. brassicoides Walsh. Yet not a gall either of that kind or of any other kind, whether Cecidomyidous or Tenthredinidous, can be seen on the S. alba trees, even on the closest examination before and after the fall of the leaf. 

S verruca 

Oct. 11th I found several of these galls on S. discolor, undistinguishable from those found on the closely allied S. humilis. The larva was orange-color with the usual whitish bowel-like markings, .08 inch long, 2.33 — 3 times as long as wide, depressed, with a large head. Breast-bone black, elongate-semi- oval and rather longer than wide. Two specimens. Thus we have no less than 4 species of Cecidomyidous galls common to the two closely- allied Willows, S. discolor and S. humilis, viz : S. gnaphalioides, S. siliqua, S. batatas and S. verruca. 

S semen

This is not a Cecidomyidous, but an Acaridous gall, and is constructed on the same principle as 15 or 16 others with which I have become acquainted, all growing on the upper side for the most part of the leaf of various trees, and composed of a more or less elongate sack opening below by a more or less closed aperture, and on its interior surface covered with rough excrescences of different shapes On the other hand, all Cecidomyidous galls known to me are smooth and free from excrescences inside. From most of these Acaridous galls the mites escape through the aperture below, but in some, e. g. Cerasi crumena Walsh MS, on Cerasus serotina, the gall always bursts open above as in Salicis semen. Similar, but not identical, galls are found on several other Willows. On Aug. 25 I found in one of these S. semen galls, which was about .03 inch in diameter, as many as 40 or 50 hyaline-whitish young Acarus, which, as is usual, were much more elongate than the perfect Mite. Hence it may be readily understood how minute their size is, and how liable they are to be overlooked, except under a very powerful lens, especially as, un- like the perfect Mite, they are very dull and sluggish in their motions, which indeed seems to be the universal rule with all the larvae of the (Jail-making Mites. The perfect Mite, which was found on the same day in other galls, is hyaline-whitish with antenuiform front legs as long as its other legs, which front legs it elevates in the air and constantly vibrates up and down as it runs. Those found in galls on other trees differ but little in Bize, structure or color, some species however being spotted. In a few galls, e. g. Crataegi vermiculus Walsh MS, which occurs abundantly both on Crataegus tomentosa and Cr. crus-galli, the larvae of the mite are of a pale pink color.

S aenigma

I have little doubt that this gall also is a deformation produced by an Acarus. From its great scarcity in 1866. 1 was unable to examine any green specimens, but on Aug. 27 I found among the crumpled exterior surface of a partly dried-up specimen a half-grown Acarus similar to those found in S. semen. It may be stated that on the tree from which this gall was procured there were no S. semen galls ; for this gall too, as well as S. aenigma, though so exorbitantly abundant in 1864 has been comparatively quite scarce in 1866. Usually in Acaridous galls the larvae live in a hollow inside; but in one on the leaf-stalk of the Black Walnut — Juglandis caulis Walsh MS — they reside among the brown external woolly pubescence, just as in S. aenigma they probably reside in the crumpled external surface of that gall. The Cecidomyidous larva) that I found in June and August in S. aenigma were most likely inquilines. (Proc. etc. III. pp. .608 — 9.) I have received through Mr. Bebb from Cr. W. Clinton, Esq., Buffalo, N. Y., pressed specimens of this gall growing on the same Willow — S. nigra — on which I find it exclusively. Hence there are at least 3 Willow-galls common to the Eastern and the Western States — S. strobiloides, S. siliqua, and S. aenigma.

S ovum n. sp.

On Salix cordata [eriocephala]

An oval or roundish sessile monothalamous swelling, .30 — .50 inch long, placed lengthways on the side of small twigs, green wherever it is smooth, but mostly covered with shallow longitudinal cracks and irregular rough scales which are pale opaque brown. Its internal substance fleshy in the summer like that of an apple, but with trans- verse internal fibres. When ripe in the autumn, filled with reddish-brown spongy matter, with close-set transverse internal fissures at right angles to the axis of the twig. On cutting down to the twig at any time, a longitudinal slit about .20 inch long becomes plainly visible. Particular twigs on badly infested bushes sometimes have one of these galls about on every half inch of their length, and not placed in a regular row, but indiscriminately on any side of the twig. Abundant but local. Described from very numerous specimens. 

S ovulum n. sp.

On Salix humilis

Undistinguishable both internally and externally from S. ovum n. sp. But for the fact that the larvae differ in color, and that, of the five species of willow found near Rock Island, IL., this type of gall occurs only on S. humilis and S. cordata [eriocephala] — two willows which are, according to Mr. Bebb, very distinct — and never, as I have carefully observed, on S. discolor — which is on the same authority, very closely allied to S. humilis, the species on which S. ovulum is found — I should not suppose S. ovulum to be a distinct (phytophagic) species from S. ovum. Possibly, indeed, it may not be so and to determine doubts it is better to await the discovery of male female imago. Besides the three bushes of S. discolor mentioned above, (Proc. Ill, p. 589,) I have since discovered and examined closely several dozens. This gall was rare in 1864 — 5 and 1865 — 6, but common in 1863 — 4. Not local, but generally distributed. Described from 30 specimens.

S pomum, n. sp.

On S cordata [eriocephala] (and very rarely on S discolor]

A smooth, fleshy, sessile, globular or slightly oval, monothalamous gall, re- sembling a miniature apple, .30 — .55 inch in diameter, growing on one side of the midrib of a leaf, and extending to its edge or sometimes a little beyond it. The principal part of the gall generally projects from the under side of the leaf, and only about 1-6th of its volume from the upper side, although very rarely it is almost equally bisected by the plane of the leaf. Scarcely ever more than one gall on a leaf, and very rarely two of them more or less confluent, so as to seem like one kidney-shaped gall. External color greenish-yellow, generally with a rosy cheek like an apple, especially on the upper surface, and often with many dark little dots on its surface. Internal color whitish. The above is the appearance presented July 31 when the gall is fully matured, but as early as May 24 it has nearly attained its full size, and has the rosy cheek very conspicuous. Abundant but rather local. Described from very numerous specimens. As to the occasional occurrence of this gall on S. discolor see under [No. 21 bis.](https://www.gallformers.org/gall/3549) An analogous gall is formed in Europe on the leaves of various kinds of willows by Nematus gallicola Westw.

S pisum, n. sp.

On Salix discolor

A subspherical, pea-like, hollow, pale yellowish-green gall, always growing on the under side of the leaf. and almost always from one of the side-veins, very rarely (1 specimen) from the midrib, and attached to the leaf by only a minute portion of its surface, .18 — .28 inch in diameter, and a few, which were probably immature or abortive, only .08 inch in diameter. Almost invariably there is but one gall to one leaf: but on 4 leaves there were two, and on 2 leaves three of them, and occasionally two are confluent. The surface of the gall is without pubescence, in some smooth and even, in others a little shrivelled, generally studded in the medium-sized ones with 4 — 12 small, robustly conical nipples, which in the larger ones have hurst into a scabrous brown scar. Only in 3 out of 62 galls was there any rosy cheek, as in S. pomum. The point of attachment is marked on the upper side of the leaf by a brown sub-hemispherical depression about .04 inch in diameter. Abundant but local. Described Aug. 25 from 62 freshly-gathered galls. At the time the 1st part of this Paper was published I was unacquainted with this gall, which accounts for the irregularity in the numbering, (21 bis.) 

On the same bush with the above there occurred 13 galls, mostly unbored, so identical in appearance with S. pomum that I did not think it worth while to attempt to breed from them. On Oct. 14, out of another lot of S. pisum on another bush of S. discolor, I found that about one-fourth to one-fifth had a slightly rosy cheek. On this bush also I met with 4 S. pomum in company with S. pisum. but all empty and bored, but whether bored by the Gall-maker or by the inquilinous Anthonomus sycophamta. n. sp. (Coleoptera) is uncertain. In both the above two cases a few S. discolor bushes were growing in the midst of very large numbers of S. cordata [eriocephala], the species on which S. pomum is normally found. This gall is evidently allied to those produced by the European Nematus intercus and N. gallarum, which are described as "globose, spongy, pedunculated galls along the mainrib of the leaf;" but it differs in growing, not exclusively from the mainrib, but indiscriminately from any of the veins. Distinct from S. pomum by its being peduncled not sessile, and by its smaller size and the general absence of a rosy cheek, and from S. desmodioides by its short peduncle and by its very different shape. 

But from a gall on the same plant, and also on the allied Compositous plant *Vernonia fasciculata*. which is externally like the Lepidopterous gall [probably here referring to the gall of *Gnorimoschema gallaesolidaginis*], but is internally filled with brown sponge and numerous cells, I have bred many specimens of *Lasioptera solidaginis* O. S., a minute Cecidomyidous fly. Whether this Dipteron is inquilinous in the Lepidopterous gall, or the Lepidopteron in the Dipterous gall, or whether the two galls are distinct and both the Dipteron and the Lepidopteron are gall-makers, I cannot say with any certainty ; but on mature consideration of all the facts now known to me, I incline to the last supposition.

But from a gall on the same plant [*Solidago* sp.], and also on the allied Compositous plant *Vernonia fasciculata*. which is externally like the Lepidopterous gall [probably here referring to the gall of *Gnorimoschema gallaesolidaginis*], but is internally filled with brown sponge and numerous cells, I have bred many specimens of *Lasioptera solidaginis* O. S., a minute Cecidomyidous fly. Whether this Dipteron is inquilinous in the Lepidopterous gall, or the Lepidopteron in the Dipterous gall, or whether the two galls are distinct and both the Dipteron and the Lepidopteron are gall-makers, I cannot say with any certainty ; but on mature consideration of all the facts now known to me, I incline to the last supposition.

On the Insects, Coleopterous, Hymenopterous & Dipterous: Inhabiting the Galls of Certain Species of Willow. Pt 2nd and last