 Acarus semen

Salicis semen

 Eriophyes? salicasemen

  Cecidomyia salicis semen

Eriophyidae

Eriophyes

Salix nigra

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Eriophyes semen

S semen, n. sp.

On Salix nigra

A minute, monothalamous, hollow, irregularly hemispherical, greenish yellow gall, .02 — .04 inch in diameter, mostly on the upper side of the leaf, and often, but not always, with a pointed nipple on the middle of the hemisphere, always with a corresponding circular depression on the other side of the leaf, in the middle of which is a very minute, flattish hemisphere. Very frequently on one and the same leaf the position of the gall is reversed from the ujjper to the lower side, as in Q. pihiloe Walsh. On a single leaf scores of them may often be counted, generally with several masses among them, composed of two or more confluent galls. Commences its growth early in the summer, and by the last of August many are found to be burst open at top, yet at the same time very many of them, when opened, are found to be solid without any central cell. By November most of the galls from which I attempted to breed the insect had burst open into a ragged, wart- like shape on the hemisjiherical side, but no larvte had escaped from them and none were discoverable in them. As the leaves were kept too moist, so that they moulded badly, the larvae had probably perished in the galls. Described from 20 affected leaves. From its close homology with the much larger oak-galls St/mmrtrk-a 0. S. aqd Q. pilulse Walsh, iu the former of which Cecidomyidous larvae were detected by Osteu Sacken, and described (Dipt. X. A. p. 201) as having a Y-shaped breast- bone, and in the latter of which I found myself, September 14th, several orange-colored larvje, which, from the presence of a clove-shaped breast-bone, were undoubtedly Cecidomyidous, and from the fact of a similar leaf-gall on a Willow, *S'. verruca n. sp., being inhabited by a Cecidomyidous larva, there can be no doubt, I think, that the gall S- semen is the work of a Grall-gnat. Prodigiously abundant and very common everywhere in Rock Island County, Illinois, on the Black Willow, the foliage of whole trees being thickly frosted over by it, so that the leaves look like nutmeg-graters. I have in a cursory manner noticed in July several specimens of what seemed a very similar gall ou S. discolor, but found no larva) in them ; and in a single instcince I found, August 20, two leaves of S. longifolia on a twig which grew out of a bunch of the galls S. brassicoides, covered so densely with some- what similar galls as to be intermediate in appearance between S. se- men and *S'. penigma. On August 29 I discovered in one of the cells of this gall a minute, pale-colored, apod larva with a large, scaly head, and the disk of its dorsum, but not of its venter, fuscous. This so ex- actly resembled a much larger larva of which I have found many spe- cimens in the Cecidomyidous gall, Q. pilidx Walsh, and which I am sure, from comparing it with the larva of Anthonomus scutellatus Schonh., must be Curculionidous, that I believe it to be also Curculionidous, and inquilinous, like the othei* larva, iu the gall where it occurred. I have noticed towards the last of August galls about the size of the head of a large pin. similar to S. semen, and often similarly confluent, o'rowino- in con.siderable abundance on the leaves of the River Kirch (Betula nigra), chiefly or almost entirely on their upper surface. And on the leaves of the Button-bush (Cephalanthus) I have noticed at the same period of the year galls of the same character, in the same luxuriant profusion as S. semen occurs on the Black Willow, whole bushes being covered with them ; but in neither of the two kinds could I discover any larvae. I believe them both to be the work of Cecidomyia. It does not follow, because all these galls are so small, that therefore their Gall-gnats must be abnormally small. The gall S. rhodoides n. sp. is about 4 times as long and wide as the Grail S. gnaphalioides n. sp., yet the Gall-gnat produced from the latter is only \ shorter than the (rail-gnat produced from the former. Larva, pupa and imago unknown. 

On the Insects, Coleopterous, Hymenopterous & Dipterous: Inhabiting the Galls of Certain Species of Willow. Pt 1st--Diptera

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.

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

Eriophyes semen

Cecidomyia salicis-semen
Acarus salicis-semen

A small, monothalamous, sac-like, rounded gall. About 1 mm in diameter. Usually on upper side of the leaf with the opening below. Found in large numbers on the leaf affected. Begins in early summer, matures with the leaf. On willow, Salix.

Insect galls of Springfield, Massachusetts, and vicinity

Eriophyes semen

Irregularly hemispherical, greenish yellow, pocket gall on either surface, on S nigra.

Eriophyes sp.

Small and very crowded, pocket galls on leaves of S nigra

Key to American Insect Galls

Eriophyes semen

Salix
Capsule or pocket galls, plant mites, spring and summer

Irregularly hemispherical, greenish-yellow pocket galls on either surface of black willow leaf

Plant Galls and Gall Makers

Eriophyes? semen

Cecidomyia salicis semen
Eriophyes? salicasemen
Salicis semen
Acarus semen

Hosts: Salix nigra

Relationship: Galls; a pocket or capsule-gall irregularly hemispherical, greenish yellow, with a projecting aperture; on both surfaces, mostly upper.

Range: IL, IN

Eriophyes? salicaesemen [listed as junior synonym of Eriophyes? semen]

Host: Salix nigra?

Relationship: Galls

Range: IL

Notes: The gall was originally described in 1864 as Salicis semen. See Chadwick 1908, p. 146, for early synonymy. This name was missed by Davis et al., 1982. Is this gall-forming mite the same as Aculus tetanothrix (Nalepa)? Is it another sibiling species? Then, salicaesemen would hold priority. Amrine & Stasny (1994) combined the two names provided by Walsh without knowing that it had already been designated semen by other authors.

Amrine Catalog