882 CHARLES PauL ALEXANDER 
at tip, with two teeth at about midlength. Maxilla with outer lobe greatly prolonged into 
a flattened blade. Antenna cylindrical or clavate, with three or four long papillae at tip. 
Mentum not chitinized, in FE. cinerea with a flattened rectangular plate on either aide; this 
armed with numerous hooks and spines. 
Pupa.— Cephalic crest of various shapes and sizes, very reduced in Eriocera spinosa. 
Antennal sheaths of males of several species (EH. spinosa, E. longicornis, E. cinerea) very 
long, extending beyond end of wing pad. Pronotal breathing horns of various shapes, acutely 
pointed in EH. spinosa, short and blunt in several species. Head and thorax often witi 
spines or tubercles on scape of antenna, on labrum, or (in EH. spinosa) on face of eye; a 
tubercle on scutellum (in E. longicornis), one on dorsum of second abdominal segment (in E. 
spinosa). Abdominal segments with a conspicuous transverse armature of spines near 
posterior margin. Lateral spiracles large, distinct. 
Eriocera is an extensive genus (including approximately 150 species) 
of medium-sized to large flies, most of which are tropical. The genus 
has not been found in Europe, but elsewhere it is represented by a host 
of species. The habits of the adult flies have already been noted (page 
704). The immature stages are spent in sand or gravel near running 
water, more especially along large streams. A more complete account 
of the genus is given by Alexander and Lloyd (1914) and by Alexander 
(1915 c: 148-152). 
The occurrence of the flies is somewhat local. During an entire summer 
of collecting in Maine in 1913, the writer did not find a single specimen 
of any species; and Dr. Dietz has stated that the only living individual 
which he has found was a single male of Eriocera spinosa taken in the 
Pocono Mountains in Pennsylvania. On the other hand, the flies ar 
often found in countless numbers, and several species may be foun 
associated together. Thus, at Ithaca, New York; in the sandy grave 
along Cascadilla Creek, the immature stages of four species of Eriocer 
and one of the closely related Hexatoma occur together in unlimite 
numbers. 
The species of Eriocera may be separated by the following keys: 
Larveoe 
1. Lobes surrounding spiracular disk obsolete or neariy so; a flat, chitinized plate with ser 
rate margins on either side of mental region................. E. cinerea Alex. (p. 886 
Spiracular disk surrounded by four slender lobes; no plate as described above on ment 
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2. Very large (length 40-45 mm., diameter 4-5 mm.); spiracular disk with ventral lob 
narrowly lined with black, inner ends of each forked, Y-shaped; lateral lobes narrowl 
\ lined with black, inner ends of marks expanded........... E. spinosa (O. 8.) (p. 88é 
eae (length under 30 mm., diameter under 2.5 mm.); spiracular disk not marke 
as above 
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