888 Charles Paul Alexander 



setae on outer face before tips; viewed from above, these setae seen to be separated by a 

 deep U-shaped notch; eighth segment with a dorsal pentagon of five closely approximated 

 lobes; just laterad of these a group of three setae, the posterior one long and slender, the 

 anterior one short and stout; pleural region produced into a long lobe tipped with a slender 

 seta; on sternum two small setae on either side. Female cauda (Plate LIII, 261) elongate, 

 tergal valves very long and slender, two delicate setae on either side before tip and a stouter 

 one at tip. 



Nepionotype. — Ithaca, New York, April 28, 1917. 

 Neanolype.— Fall Creek, Ithaca, May IS, 1917 

 Paratypes. — Larvae and pupae with types. 



Eriocera longicornis (Walk.) 



1848 Anisomera longicornis Walk. List Dipt. Brit. Mus., vol. 1, p. 82. 

 1869 Eriocera lofigicornis O. S. Mon. Dipt. N. Amer., part 4, p. 253-254. 



Eriocera longicornis is probably the commonest species of the genus 



in the eastern United States. The adult flies are sometimes very abundant, 



occurring in swarms in late afternoon and early evening in May, some 



of the swarms numbering thousands of individuals. At other times of 



the day, the flies may be found resting quietly on bushes. The larvae 



live in the sand near the water's edge. The pupal duration is seven days. 



The detailed life history of this species is given on pages 704 to 708. 



Larva. — Length, 17-19 mm. 

 Diameter, 2-2.3 mm. 



Color, greenish brown. 



Body covered with a long, appressed, dark pubescence. Penultimate segment of abdomen 

 capable of great distention and destitute of pubescence; last segment of body conspicuously 

 narrowed. Spiracular disk (Plate LIV, 265) surrounded by four slender lobes, the ventral 

 pair the longer, bearing at tip elongate hairs, some of which exceed the lobes in length; on 

 lateral face at about midlength a small pencil of hairs; on ventral face one or two long setae; 

 inner face of ventral lobes lined with pale brown, beginning as a narrow brown mark at tip, 

 at about midlength gradually expanded into an elongate triangular mark, the two lines 

 inclosing between their inner ends a pale linear mark; lateral lobes similar to ventral lobes, 

 fringed with long yellow hairs which are longer than the lobes; inner face of lateral lobes lined 

 with pale brown. Spiracles rather large, separated by a distance equal to about one and one- 

 half diameter of one. Anal gills pale. A few setae in transverse alinement on last segment 

 behind lateral lobes. Two pairs of short black setae behind gills. 



Head capsule and mouth parts very similar to those of Hexatoma, dorsal plates of capsule 

 separate from each other, not fused as in the Ulomorphae; inner margins of dorsal plates 

 straight and parallel. Labral sclerite broadly transverse, narrowed at ends, lateral margins 

 produced into long lobes which are densely tufted with short, golden-yellow hairs. Median 

 lobe of epipharyngeal region projecting, provided with two large sensory papillae, one on 

 ether side, and a few other setilerous papillae near tip, surrounded by numerous hairs. 



