ao4 



preying upon those most insidious and unmanageable of all the insect- 

 foes of the farmer — subterraneous root- feeding larvae. 



Tabanus — ■ — ? Imago cf. Blackish. Legs blackish; wings 

 brownish-fuscous. Length .70 inch. Expanse 1.30 inch. One de- 

 cayed specimen came out between June 14 and July 14, 1861, from 

 a larva found early in June. 



Larva (from two living specimens, obtained August 14th, 1860, and 

 September 2d, 1863). Length 2.25 inch when extended, 1.75 inch 

 when contracted; diameter .25-.30 inch. The specimen found in 

 1863, .25 inch shorter. Body cylindrical, twelve-jointed, the three or 

 four terminal joints much tapered at each end of the body, but more 

 so anteriorly than posteriorly, and joints one and eleven, each with 

 a retractile membranous prolongation at tip. Joints one to ten are 

 subequal ; eleven is about two-thirds as long as ten, and twelve about 

 one-fourth as long, and .05 inch in diameter. 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 two to eleven, the anterior annulus laterally connected with 

 the posterior by two to four dark-green lines. On the dorsum of four 

 to nine, and more obscurely on ten, a dark-green basal ti'iangle, ex. 

 tending half-way to the tip ; joint one with paler markings, and with 

 no dark annulus behind ; joint twelve entirely fuscous. Head small, 

 apparently fleshy, pale, truncate-conical, .03 inch wide, and about .04 

 inch long in repose, inserted in joint one without any shoulder 

 The trophi occupy two-thirds of its length, but it has a long cylin 

 drical internal prolongation, extending to the middle of joint two, 

 which is sometimes partially exserted, so that the head becomes twice 

 as long as before. All the trophi are pale and apparently fleshy, ex- 

 cept the mandibles, which are dark-colored and evidently horny, and 

 they have no perceptible motion in the living insect. The labrum 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 shoi'ter, and on 

 each side of it is a slender palpiform, but exarticulate maxilla, extend- 

 ing beyond the rest of the mouth in an oblique direction. No palpi. 

 On the vertex are a pair of short, fleshy, exarticulate, filiform antennae, 

 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 anten- 

 nae, 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 maxillae are 

 traceable to two-thirds of the distance from the tip to the base of the 



