WERNER MARCH AND 61 



about twice as long. The larvae are not tuberculate, but the margins of each 

 segment from the third to the tenth, especially the front margins, are more or less 

 raised into low rounded rings. On a larva with arched body definite transverse 

 impressions behind the anterior fleshy annulus of each segment are apparent 

 under magnification. They render the annuli conspicuous enough, in fact, to 

 give an impression as of false feet to the naked eye observing the larvae crawling." 



"The mouth parts are exceedingly minute and hard to observe. In arrange- 

 ment they suggest those of the full grown larva, described below, and the homol- 

 ogies have been made out accordingly, and, it is hoped, successfully. The 

 drawing [Plate 7, Fig. 95, a, h] is strictly diagrammatic and is made up from a 

 number of studies of larval heads, none of which showed all the parts in the posi- 

 tion used in the drawing." 



"Labrum {Ibr.) short, pointed, black-tipped, and slightly curved downward. 

 Labium triangular, not bifid as in full-grown larvae. Maxillae {mx.) fleshy, 

 truncate-conical, with a short downwardly projecting lobe on the inner side of the 

 distal end; palpus (mxp.) arising from the end of the maxilla, first joint long, 

 somewhat enlarged distally, tipped by a number of short rods or spines, one of 

 which is larger and blunt. It may be considered a second palpal joint surrounded 

 at the base by a group of spines. Mandibles {md.) fleshy, blunt-tipped, crenu- 

 late on lower edge, lying just inside of maxillas. Antennas {ant.) straight, tapering, 

 directed forward; basal joint as long as first palpal joint, somewhat expanded dis- 

 tally, second joint double, one of its divisions longer and apparently tipped with 

 a seta." 



"First segment of body slightly inflated, first and second segments convex 

 above, flattened beneath, lower lateral edge rather prominent. Second and 

 third segments with two or three longitudinal furrows on each side. Second seg- 

 ment with two conspicuous well separated elongate brownish spots visible (ap- 

 parently somewhat under the surface) on the dorsal aspect. Hind margins of 

 segments becoming more undulate posteriorly, markedly so on ninth and tenth 

 segments. Last segment with two round black spots, (spiracles) Graber's organ 

 (?), set close together on the median dorsal surface; this segment with two more 

 prominent ventral tubercles, two similar lateral ones, and other minute tubercles." 



Both Walton and McAtee have seen the organ of Graber in the 

 young larva of Goniops; the former speaking of a resemblance to 

 spiracles, while the latter seems frankly to believe that he is dealing 

 with spiracles. For a possible derivation of this organ from spiracles 

 we possess, however, no evidence, except that in tabanid larvae all 

 spiracles except the terminal ones have disappeared. 



Full Grown Larva (Plate 7, Figs. 92, a, b, c, and 94). — The full 

 grown larva described by McAtee is one of two collected by Theodore 

 Pergande, near Cabin John Bridge, Maryland, April 13, 1899, They 



