252 REPORT OF THE COMMISSIONER OF- AGRICULTURE. 
Larva (P1. VI, Fig. 3)—Length 2.8™™; diameter in middle of body about 4 of the length; ellipsoidal, 
sub-cylindric, flattened ventrally, tapering but slightly at the ends, which are rounded when at rest; 
surface minutely granulate. Joints well separated. Color, bright orange-red, inclining to pink when 
mature. Head small, brownish, sub-acute, and furnished with two prominent exarticulate antennal 
tubercles, which arise from lateral swellings and which are as long as the head proper is wide at base; 
basal piece or neck (erroneously considered an additional joint by some writers), into which the more 
horny pert recedes, sub-quadrate. Abdominal joints sub-equal in length, except the last, which is very 
small, bilobed, and nearly surrounded by the penultimate joint. Stigmataraised on short tubercles which, 
from a ventral view (as in the figure), are seen projecting laterally from the anterior third of each of the 
first seven abdominal joints (jts. 4-10). The pro-thoracic and the eighth pair of abdominal spiracular 
tubercies are visible only upon a dorsal view, and are situated at the hind border of their respective - 
joints, the former directed forward and the latter backward. The three thoracic joints and the two 
anal joints have each a strong lateral bristle. The ‘‘breast-bone”’ is honey-yellow, the stem narrow, 
the club with a circular notch in front and produced laterally, so as to have in all, four rather blunt 
points as in the figure. 
ep cenoie;- Broadly ovoid, 2™™ Jong, opaque, tough, composed of very light gray silk, usually covered 
wi : 
Pupal exuvium—Dirty white, with the antennal sheaths honey-yellow and projecting each side like 
the handles to an urn, the capitate bristles of moderate length, fine, and white. 
Female—The denuded body of the female is bright red. Normally, however, each abdominal joint 
has a band of black, lanceolate scales, which obscure the color unless the body be stretched. Venter 
yellowish-gray, hairy. Legs brown outside, lighter inside. Head black. Antennz yellowish-red ; 
16-jointed ; joints sessile; the two basal joints globose, the rest sub-cylindrical, narrower anteriorly than 
posteriorly, convex in front, concave behind; hairs sparse, as long as the joint, and curving forwards; 
no definite number of whorls. Palpi about as long as face; 4-jointed; jt. 3 as long as 1 and 2 a 
_ jt. 4 one-fourth longer; all armed with short, sparse hairs. Halteres reddish-yellow, clavate. ings 
closely pubescent, the fringe extending from the second vein to the hind base; transverse vein indistinct, 
and often invisible in specimens mounted in balsam. Ovipositor 4-jointed, telescopic; last joint with a 
ventral terminal slit; basal joint twice 2s long as broad; second joint four times as long as first; third 
joint three times as long as first; fourth joint as long as basal joint. 7 
Male—Antenn® 15-jointed; two basal joints globose, the rest pedicelled; the pedicels white and as 
long as the globular part, which is nearly black; [left antenna of one specimen with but 14 joints, ow- 
ing to a coalescence of the 5th and 6th]; more hairy than in the female, but with no definite number e«f 
whorls. Genitalia broad, prominent, protruded by a slender pedicel; each clasper consisting of a swol- 
len basal joint and a terminal hook, which is obliquely truncate at tip. 
Many specimens examined. 
These Cecidomyiz are often quite difficult to rear to the perfect state, and it has been customary to 
name them from the lary when these produce, as they very frequently do, galls or other abnormities 
of the food-plant, by which the species is readily recognized and distinguished. There is some discrep- 
ancy between the above description of the larva and that given by Mr. Lintner, who describes the lateral 
fleshy tubercles as arising ‘‘at about the middle of each segment,” and does not mention the stigmata. 
Yet I cannot doubt but that the insect under consideration is the same species examined and studied 
by my friend. 
Compared with the two other most destructive species of the genus—tritict and destructor—trifolit 
shows the following differences. The former has, on an average, 24 joints in the male and from 12 to 13 
in the female antenna. Destructor has sometimes as many as 20 in the male and 19 in the female, 
though authors give an average number of 17; while trifolii has 15 in the male and 16 in the female. 
The number of joints varies, so that upon this character alone, unless there is great difference, specific 
distinctions cannot safely be founded. 
In both tritici and destructor the joints of the female antennsw are pedicelled, while in trifolit they 
are sessile. In trifolii the palpi are 4-jointed, as they are also (according to Curtis) in tritict, while in 
destructor they are 3-jointed. In érifolii the transverse vein is present though indistinct; in tritict it is 
distinct, and in destructor it is absent. In ¢trifolit the ovipositor is 4jointed; in tritici and destructor it 
is described as 2-jointed; but here again the descriptions are at fault, due no doubt to the fact that the 
basal joint has been considered the terminal abdominal and that the separation of the 3d and 4th is readily 
overlooked. The male genitalia are larger and more prominent in ¢rifoliit than in either of the 
others. The larvee of trifolii and tritici are very similar. The anal joint of tritici is, however, armed 
with six strong, pointed tubercles, which are not present in ¢trifolii, while the antennal tubercles are 
longer. The spiracular tubercles are similar, but in tritici they are more dorsal and cannot be seen 
from a ventral view, while the jast pair [on joint 11] is more prominent. The angles of the “‘ breast- 
bone” in tritici are somewhat more rounded than in ¢rifolit. 
The larva of destructor differs radically from either of the others. Itis about twice as large, and joints 
10, 11, and 12 are crowded so closely together that it is difficult to distinguish them. The anal joint 
bears two rounded tubercles at tip. The spiracular tubercles are not perceptible; the head is more 
rounded than in trifolii ; the antennal projections are much shorter. The ‘‘breast-bone” is smaller, the 
club being but little larger than the stem, which is slightly enlarged at base. The lateral angles te 
the club are entirely wanting. 
