Adult Males
(modified from Epler 1987)
In addition to the generic description, the species in the key below have the following traits: Inferior volsella with simple apex, at most notched, appearing shallowly bifid or trifid, without a membranous dorsal extension; anal point not sharply reflexed ventrad, visible in dorsal view.
1a | Superior volsella strongly pediform, apex directed outward | 2 |
also: Sensilla chaetica not restricted to posterior margin of volsella; legs not banded, at most distal poirtions of some leg segments darker; anal point not with a raised truncate base; dorsum of tergite IX not with many long setae laterad of anal point; gonostylus inflated medially, narrowed proximally and preapically | ||
1b | Superior volsella digitform, long and slender, or long with weakly expanded membranous apex; if somewhat pediform, then apex directed inward | 3 |
2a(1a) | a. Gonstylus inflated medially, narrowed proximally and preapically | Dicrotendipes neomodestus (Malloch) |
b. General coloration brown | ||
2b | a. Gonostylus not as above | Dicrotendipes modestus (Say) |
b. General coloration green to red-brown | ||
3a(1b) | Superior volsella short, digitform | 4 |
3b | Superior volsella long and slender, or long with weakly expanded membranous apex | 7 |
4a(3a) | a. Anal point with a wide, shelf-like base, tapering gradually to apex | Dicrotendipes fumidus (Johannsen) |
b. Superior volsella cylindrical, with slightly out-turned apex | ||
4b | a. Anal point spatulate or narrowed at base | 5 |
5a(4b) | a. Superior volsella with thin membranous preapical extension | Dicrotendipes leucoscelis (Townes) |
b. Metatarsi usually with a wide basal white band | ||
5b | a. Superior volsella not as above | 6 |
b. Metatarsi without a wide basal white band | ||
6a(5b) | a. Anal point long, narrowly spatulate | Dicrotendipes lobiger (Kieffer) |
b. Superior volsella with a sclerotized area at apex | ||
6b |
a. Anal point and superior volsella not as above | 7 |
7a (3b,6b) | a. Superior volsella long, slender, recurved, with an acute apex | Dicrotendipes botaurus (Townes) |
7b | a. Superior volsella not as above | 8 |
8a(7b) | a. Apex of superior volsella turned in | 9 |
8b | a. Apex of superior volsella turned out; or straight, semiglobose | 10 |
9a(8a) | a. Gonostylus long, thin, and strongly curved | Dicrotendipes milleri(Townes) |
b. Superior volsella usually without microtrichia, its apex at most semimembranous | ||
9b | a. Gonostylus not as above | Dicrotendipes tritomus (Kieffer) |
b. At least the basal half of superior volsella with microtrichia, its apex membranous | ||
10a(8b) | a. Sensilla chaetica of superior volsella in a line often reaching the middle appendage of the appendage tip, not directed exclusively inward | Dicrotendipes nervosus (Staeger) |
b. Length of superior volsella 2-3.25x its maximum width | ||
c. Wing with > 35 setae on R and R1 | ||
10b | a. Sensilla chaetica of superior volsella distributed on the inner surface of the appendage, the majority directed inward | Dicrotendipes lucifer (Johannsen) |
b. Length of superior volsella 4.25-5.25x its maximum width | ||
c. Wing with < 35 setae on R and R1 | ||
Pupae (modifed
from Epler 1987)
Dicrotendipes botaurus Townes not keyed
1a a. Ventral spine row(s) absent 2 1b a. Ventral spine row(s) present on S II 4 2a(1a) a. 5 lateral lamellar setae on tergite VIII Dicrotendipes leucoscelis (Townes) also: Anal lobe without dorsal shagreen; intersegmental spines present between tergites V and VI 2b a. 4 lateral lamellar setae on tergite VIII 3 3a(2a) a. Shagreen spinules on tergites II-V largest posteriorly, tips often rounded Dicrotendipes fumidus (Johannsen) b. Exuviae light yellow-brown to dark yellow-brown 3b a. Shagreen spinules on tergites II-V more or less equal; Dicrotendipes nervosus (Staeger), Dicrotendipes lucifer (Johannsen) (nervosus-group) b. Exuviae clear or light to dark brown also: Medial shagreen spinules on tergite VI with longest spinules in middle of area; Exuviae clear with yellowish borders 4a(1b) a. 5 lateral lamellar setae on tergite VIII Dicrotendipes lobiger (Kieffer) 4b a. 4 lateral lamellar setae on tergite VIII 5 5a(4b) a. Caudolateral spur on tergite VIII double or triple, spurs well separated 6 5b a. Caudolateral spur on tergite VIII single or closely appressed double 7 6a(5a) a. Cephalic tubercles long, thin, sharply acute Dicrotendipes milleri(Townes) b. 33-40 (mean 37) anal fin setae 6b Cephalic tubercles shorter, wider Dicrotendipes tritomus (Kieffer) 33-55 (mean 45) anal fin setae 7a(5b) a. Posterior spinules of median shagreen area on tergite VI larger, more rounded or longer than those of the anterior poirtion of the shagreen area Dicrotendipes tritomus (Kieffer) b. Caudolateral spur on tergite VIII not strongly sinuate or recurved, almost straight 7b a. Posterior and anterior spinules of median shagreen area on tergite VI more strongly developed than those of the center 8 b. Caudolateral spur on tergite VIII usually strongly sinuate or recurved 8a(7b) a. Anal lobe with 31-50 (mean 38) lateral setae Dicrotendipes neomodestus (Malloch) 8b a. Anal lobe with 30-64 (mean 50) lateral setae Dicrotendipes modestus (Say)
Larvae (modifed
from Epler 1987)
D. botaurus Townes and D. milleri Townes not keyed
1a a. Frontal apotome with a large anteromesal oval or subquadrate area 2 b. Frontal pit or process absent 1b a. Frontal apotome without such an area 3 b. A small anteromedian frontal pit or frontal process usually present 2a(1a) A frontoclypeal apotome present Dicrotendipes lobiger (Kieffer) Sixth lateral tooth of mentum well-developed also: Ventromental plate with 30-41 (mean 35) strial ridges 2b A fronto apotome present Dicrotendipes leucoscelis (Townes) Sixth lateral tooth of mentum reduced or closely appressed to 5th also: Ventromental plate with 37-60 (mean 52) strial ridges 3a(1b) a. Mentum with second lateral tooth almost completely fused with, or closely appressed to, the 1st, so that the 1st lateral tooth appears notched 4 3b a. Mentum with second lateral tooth at most only partially fusted to 1st lateral at base, 1st lateral tooth not appearing notched 5 4a(3a) a. Head capsule integument appears coarsely granular at 400x Dicrotendipes fumidus (Johannsen) also: Postmentum or posterior portion of head capsule usually not darkened, rather yellow-brown to yellow-red-brown; 1st lateral teeth of mentum often turned outward 4b a. Head capsule integument at most appears slightly granular at 400x Dicrotendipes neomodestus (Malloch) also: Anal tubules not reduced; at least the anterior outer margin of the ventromental plate usually crenulated 5a(3b) a. Proximal tooth of mandible saddle-shaped or with 2 points Dicrotendipes lucifer (Johannsen) also: Sixth lateral tooth of mentum pointed 5b a. Proximal tooth of mandible mostly triangular in outline, not as above 6 6a(5b) a. Sixth lateral tooth of mentum rounded and closely appressed or fused to fifth lateral tooth Dicrotendipes nervosus (Staeger) 6b a. Sixth lateral tooth pointed, separate 7 7a(6b) Head capsule pale light brown to brown Dicrotendipes modestus (Say) also: Anterior margin of ventromental plates with shallow to moderate crenulations 7b Head capsule pale yellow 8 8a(7b) a. Ventromental strial ridges 28-36 (mean 32) Dicrotendipes modestus (Say) b. Postmentum usually darkened 8b a. Ventromental strial ridges 23-29 (mean 25) Dicrotendipes tritomus (Kieffer) b. Postmentum rarely darkened
Page created: September 24, 2003; Last edited: November 8, 2013 (EB)