130 SECOND ANNUAL REPORT OF 



quiet at the bottom. The specimen which I succeeded in breeding, 

 was sent to me by Mr. Adolph Engelmann of Shiloh, St. Clair Co., 

 Ills. It was found by Mr. Wm. Cooper of the same county, about ten 

 feet from a small but permanent stream of water. Mr. C. at first took 

 it to be a leech, and when he attempted to capture it, it immediately 

 commenced burrowing in the ground. 



Mr. Walsh's description of this larva is so full, and agrees so well 

 with mine, that I cannot do better than transcribe it. 



Tabanus atratus. — Larva, — Length 2.25 inches when extended, 1.75 inches when contracted : 

 diameter .25 — .30 inch. Body cylindrical, 12-jointed, the three or four terminal joints much tapered 

 at each end of the body, but more so anteriorly than posteriorly, and joints 1 and 11, each with a. 

 retractile membranous prolongation at tip. Joints 1 to 10 are subequal ; 11 is about two-third8 

 as long as 10 and 12 about one-fourth as long, and .05 inch in diameter. [Joints 1 and 12 pear- 

 shaped when extended]. Color a transparent greenish-white, paler beneath ; an irregular dark- 

 green or greenish-black annulus, paler beneath, on the anterior and posterior margins of joints 

 2 to U, the anterior annulus laterally connected with the posterior by two to four dark-green 

 lines. On the dorsum of 4 to 9, and more obscurely on 10, a dark-green basal triangle, extend- 

 ing half-way to the tip; joint 1 with paler markings, and with no dark annulus behind ; joint 12 

 entirely fuscous. Head small, apparently fleshy, pale, truncate-conical, .03 inch wide, and about 

 .04 inch long in repose, inserted in joint 1 without any shoulder. The trophi occupy two-thirds of 

 its length, but it has a long cylindrical internal prolongation, extending to the middle of joint 2, 

 which is sometimes partially exserted, so that the head becomes twice as long as before. All the 

 trophi are pale and apparently fleshy, except the mandibles, which are dark-colored and evidently 

 horny, and they have no perceptible motion in the living insect. The lubrum is slender, a little 

 tapered, and three times as long as wide, on each side of and beneath which is a slender, thorn- 

 like, decurved, brown-black mandible. The labium resembles the labrum, but is shorter, and on 

 each side of it is a slender palpiform, but exarticulate maxilla, extending beyond the rest of the 

 mouth in an oblique direction. No palpi. On the vertex are a pair of short, fleshy, exarticulate 

 filiform antenniB, and there are no distinct eyes or ocelli. In the cast larval integument the entire 

 head, .25 inch long, is exserted, and is dark-colored and evidently horny, all the parts retaining 

 their shape except the antenna?, labrum and labium. The whole head has here the appearance of 

 the basal part of the leaf of a grass-plant, clasping the origin of the maxillae on its posterior 

 half, and bifurcating into the somewhat tapered cylindrical mandibles on its anterior half. The 

 maxilla; are traceable to two-thirds of the distance from the tip to the base of the head, scarcely 

 tapering, bent obliquely downwards at two-thirds of the way to their tip, and obliquely truncate 

 at tip. On the anterior margin of ventral segments 4 — 10, in the living insect, is a row of six 

 large, fleshy, roundish, tubercular, retractile pseudopods, the outside ones projecting laterally, and 

 each at tip transversely striate and armed with short, bristly pubescence ; on the anterior half of 

 ventral joint 11 is a very large, transversely-oval, fleshy, whitish, retractile proleg, with a deeply 

 impressed, longitudinal stria. On the anterior margin of dorsal joints 4 — 10, is a pair of smaller, 

 transversely-elongate, retractile, fleshy tubercles, covering nearly their entire width, armed like 

 the pseudopods, but not so much elevated as they are. No appearance of any spiracles. Anus 

 terminal, vertically slit with a slender, retractile thorn .05 inch long, not visible in one specimen. 

 llead, and first segment or two, retractile. 



The larva reared by De Geer was terrestrial. This larva is semi- 

 acquatic, for it is quite at home either in water or moist 

 earth. My specimen was kept for over two weeks in a large 

 earthen jar of moist earth well supplied with earth-worms. 

 It manifested no desire to come to the surface, but burrowed in every 

 direction below. I found several pale dead worms in the jar, though 

 I cannot say positively whether they had been killed and sucked by this 

 larva. Mr. Walsh in speaking of its haunts and of its food, says : " I 

 have, on many different occasions, found this larva amongst floating 

 rejectamenta. On one occasion I found six or seven specimens in the 

 interior of a floating log, so soft and rotten that it could be cut like 



