Circular

*

SB
818

C5768

ENT

6.

~J

No. 72.

_.ilted States Department of Agriculture,

BUREAU OF ENTOMOLOGY,

L. O. HOWARD, Entomologist and Chief of Bureau.

KEY TO THE KNOWN LARVE OF THE MOSQUITOES OF THE
UNITED STATES.!

By HARRISON G. DyAR.

. Larvee without a distinct air tube, the air hole with flaps but no elongated

sides ; floating at surface of water in a horizontal position. The malaria
COVA EIS 5 eae ele ee ne Subfamily ANOPHELIN®____ 3
Larvee with a distinct elongated air tube; floating below the surface of water,
Hswaliviobliquelv shanmine: bDyothe tule 2: -=22 3 eee 2

. The last segment, beyond the air tube, with a ventral brush or rudder in the

middle of the segment behind —------ > Subfamily CULICINA____ 6
Last segment without a median brush, the hairs paired on the two sides,
MOneson mid =ventraleines=—- 85 ss ss Subfamily SABETHIN
Only one species, in leaves of pitcher plants in cold bogs.

Wyeomyia smith Coquillett.

Abdomen with plumose lateral hairs on the first three segments only; head
nner MINATO Se? Naansy= 2 oe = Nl ee ee ee eee 1
Abdomen with plumose hairs to the sixth segment; head without plumose
hairs. Lives in hollow trees ___--__--_-___- Anopheles barbert Coquillett.

. Lateral comb (on the eighth segment below the air hole) with one long lower

tooth followed by fowr little ones ____ Anopheles franciscanus McCracken.
Lateral comb with one long lower tooth followed by three little ones.
Anopheles punctipennis Say.
Lateral comb with the lower long tooth followed by another as long or
TES O eee een et Oe ee ee ee 5
Lateral comb with the upper tooth Bjork ~ Anopheles maculipennis Meigen.
Lateral comb with the upper tooth long___ Anopheles crucians Wiedemann.
Mouth brush folded outward when not in use, not vibratile, used to seize
prey only. Predaceous on other mosquito larvee_______________-_-_..__- r
Mouth brush folding inward, tufted, vibratile, usually continually in motion.
Feed on microscopic organisms and vegetable detritus _________________ 9
A plate on the side on the eighth abdominal segment. Only one species,
living in hollow trees and water barrels; beneficial.
Megarhinus portoricensis von Roder.
A patch of small scales on the side of the eighth abdominal segment. Living
initemporary puddles = beneficial species; ..1 22. 25-222 222 Bl 8
Labial plate (mentum) of head with the teeth regular andl alien
Psorophora ciliata Fabricius.
Labial plate with the next to the basal tooth much enlarged.
Psorophora howardii Coquillett.

l1The generic names here used have been made uniform with those of Technical Series No. 11,

of this Bureau, to facilitate cross reference. In case of discrepancy in specific names, the names
employedin that publication are given in footnotes,

10.

a‘ /thorax,-head-..

12.

9
~

_ Antennze with tuft outwardly placed, in a notch, the apical part of antenna

slender; air tube long, over three times) as' Jong as wide. .- == === 10
Antenne with the tuft at or before the middle, the apical part not more

slender; air tube usually shorter than three times its width —-_----- Eee,
Lateral comb of the eighth segment a patch of spines__- fie AS ee eel
Lateral comb of the eighth segment a row of bars -------------~--------- 16

mouth brush

head hairs.

I j _antennal tuft

Wy / _. antenna
eye

ce:
= hair tufts

at abd.set ee gs
Sta Ee Za

Pe jiel e7— DON Wea eee

| Si eamay ee Gye, SS 2 lateral abdom.
i Ath» » ! : ee 2 hairs
c 5th» » ww... subdorsal
E 6th ae == abd. hairs
iS
RB 7thy »

i _-lateral comb

! 8th ” ” ;

era _-air tube
anal segb---~=

ene brush’

anal gills ~
ae

Fig. 1.—Diagram of a mosquito larva (Oulex salinarius), with names of the parts referred
to in the key (original).

haat tufts

Anal segment with a row of hairs along the ventral line to base; an early
spring species _---------------------+--------- Culicella dyart Coquillett.
Anal segment without any tufts in front of the Venoral Hush eaeea==—— LZ
Air tube with four paired tufts posteriorly outwardly, the subapical one

moved sideways out of line_-_--------.---------------+--------------- 13
Air tube with four to ten paired tufts along ‘the posterior line in a straight

fow, none displaced------.------- ------------------------------------ 15

13.

14.

15.

16.

ilv/e

18.

Ili),

20.

21.

Go

Air tube over five times as long as wide, nearly straight, without marked
tapering ; living in fresh-water pools, rain barrels, etc.
Culex salinarius Coquillett.
Air tube less than five times as long as wide, tapering rather rapidly after
the middle, somewhat fusiform in shape-._____._--__2_.1.._2.=_-_2__- 14
Air tube five times as long as wide, its pecten of 15 teeth; subdorsal hairs of
third and fourth abdominal segments double. Introduced domestic
BERS UNICO Mes hee ye nt OS Es Ee Culex pipiens Linnzeus.
Air tube four times as long as wide, its pecten of nine teeth; subdorsal hairs
of the third and fourth abdominal segments single. Southern domestic

TEC RR EUL CCN SEAN 9 ee Os Culex fatigans Wiedemann. !
Air tube slightly expanded at tip. Summer swamp mosquito. The adult
GOESRnObabites meets sree ee EN ie en Culex territans Walker.

Air tube evenly tapered to tip. Living in permanent pools all summer.
Culex tarsalis Coquillett.
Bars of comb in a perfectly regular row; skin smooth. Hibernates as fully
grown larva in permanent pools_____ Melanoconion melanurus Coquillett.
Bars of comb in an irregular row; skin minutely pilose.
Mochlostyrax erraticus Dyar and Knab.?
Air tube strongly inflated; anal segment with a chitinous ring, pierced by a

LOMO tULSpaLoOn ob heaventrall line 32 512s a ee ee eee 18
Air tube not inflated ; anal segment not ringed, or, if so, without tufts along
themventreal eine peewee sere 2 lest le fo i nahh oi ee ee ee 20
Nmibennsceloneyandspromimentmes 2302) ose is Se eee 19

Antenne less long, moderate only. Developing rapidly in rain puddles.
Grabhamia jamaicensis Theobald.
Lateral comb of the eighth segment of six or seven nearly equal teeth.
Developing rapidly in rain puddles__ Janthinosoma sayi Dyar and Knab.*
Lateral comb of the eighth segment of five teeth, the upper and lower
Oimngs TON) Ss ee Janthinosoma varipes Coquillett.

Antenne inflated and bent. Rapidly developing in rain puddles.

Grabhamia discolor Coquillett.
Aten motemanked ly inflated or. bent. -_1+.--2222-2 222-222-222 ee 21
Head with a lateral prominent angle which receives a process on the man-
dible. In crab holes on the Florida coast__ Deinocerites cancer Theobald.

Headmnnonoutmsrchuanednn olen (Jaci sho) Wl! 22 nas is 2d ee 2D
Headiwathetihick«club-like hairs. —-_------_..---- 2222-5 Genus Uranotenia.4
ieadewithwihe usialktime: hairs only) 2. --.222 22-2252 ee Se 23

Air tube without pecten; several chitinous plates on the abdominal seg-
ments. In hollow trees and rain barrels__-Pnewmaculex signifer Coquillett.
Air tube with pecten ; abdominal segments without any plates before the
Dir HVS so eo oe ee eee ae eee 24
Air tube bottle-shaped, the outer half linear.
Teniorhynchus perturbans Walker.
MTSU eRe SulabivebaApereG@is 252-2 22-20 le ee ee eee a 20
Air tube with a row of hairs beyond the pecten, the pair of tufts at base of
WHOS esee tele t eee eS ee apse it ni wl Gores 8 26
Air tube without a row of hairs; the tuft at or beyond the middle of the
(illegal Pe 28

1 Culex pipiens (in part). Not the true fatigans of India, but so called by Theobald. ‘he proper
name of our species appears to be Culex cubensis Bigot.

2Melanoconion atratus (in part).

3 Janthinosoma posticata.

4'Three species differentiated by minute characters. Only one species is at all common, Ura-
notenia sapphirina Osten-Sacken.

26.

28.

29.

36.

41.

4

Lower head tuft with three long hairs, the upper multiple. In permanent
water, with a northern distribution____________- Culiseta absobrinus Felt.
Lower and upper head tufts alike, multiple -_--__--______-_____________ 27
Basal pecten teeth of the air tube with one branch. In pools, barrels, etc.,
with western distribution ---_-_---__--_--_ Theobaldia incidens Thomson.
Basal pecten teeth of air tube with several branches. In pools, with eastern
and southern distribution == 2) 22 = 2 es Culiseta consobrinus Desvoidy.
Aur tulbeswith severale liars twits =e ee eee ane 29
Aimtube with only one pair oftultsioe. +2 9 e8its ae eee 30
Air tube long; anal segment with a complete ring. Living in pools and
MaMMIbAancels Sk Saw gee A 2 ee cae ae Culex restuans Theobald.

Air tube short; anal segment not fully ringed. An early spring species.
Ochlerotatus trichurus Dyar.!

Anmtube withuthevhairituitiwithin the spectent= =.= === =e eee 31
Mirtube with the hair tuft beyond the pecten) —_ 225222222 eee 33
Amalisesmentminged with a horny: plates 222s 32

Anal segment not ringed. In pot holes in rocks.
Ochlerotatus atropalpus Coquillett.
Lateral comb of the eighth segment a few scales in a row. In swamps, with
avsouthern distribution --___________=_ Aédes tormentor Dyar and Knab.?
Lateral comb of the eighth segment a large patch of scales.
Ochlerotatus bimaculatus Coquillett.

Peciten of the air tube with detached teeth outwardly _-_----_------------ 34
Pecten of the air tube with all the teeth evenly spaced __+_____._.__-_--_ 38
Air tube four times as long as wide; lateral comb of the eighth segment a

patch of scales three rows deep. An early spring species.
Ochlerotatus abfitchii Felt.
Air tube three times as long as wide or less; lateral comb of the eighth

segment or few SCales...- 2s 2520 22. eee 35
Antenne enlarged basally; tuft rather beyond the middle. An early spring
SDCCLES eee eer etee Sere rae a ee _ Ochlerotatus aurifer Coquillett.
Antennz moderate only; the tuft before the middle _____~._____________ 36

The two rows of the pecten of the air tube approximate behind; dorsal plate
of anal segment a saddle only. An early spring species.

Ochlerotatus impiger Walker.

The two rows of pecten well separated; dorsal plate more than half encir-

clinestheranal:segment =2__...-_--_--. -.-4=8-J'¢ 4 eee 37
Tuft of the tube before the outer third; anal gills blunt. In rain puddles.

Ochlerotatus sylvestris Theobald.

Tuft of tube beyond the outer third; anal processes pointed. In rain puddles.

Aédes fruscus Osten-Sacken.

Comb scales few, in a single or irregularly single row ___________ -__--- _ 39
Comb scales more numerous to many, in a patch__.____-_-_______------ 43
Anal-sesment rincedsby themplatey ses se see ee 40
Anal segment not completely ringed by the plate ~___-___- 1 Ree 2
Analgoullssmodenate; mornvall =a as ee ee ees Lp Sih yea tL
Anal gills very long with stout central trachea. In pools, not coming to the

surface; distribution southern ___________ Ochlerotatus dupreei Coquillett.
Pecten of air tube running about one-third; anal segment not longer than

wide. An early spring species _____________- Ochlerotatus punctor Kirby.

Pecten of air tube running about one-half; anal segment longer than wide.
Aédes atlanticus Dyar and Knab.?

l Ochlerotatus cinereoborealis.
2 Ochlerotatus serratus (in part).

5

. Seales of the comb of the eighth segment smooth, bluntly rounded. In

hollow trees and rain barrels ______________- Ochlerotatus triseriatus Say.
Seales of comb sole-shaped with trifid apex. The yellow-fever mosquito.
Stegomyia calopus Meigen,

foeeoar seement Tinged-by the plates: M15 ite) te) Aa ete aeons 44
Anal segment not completely ringed by the plate ______________________- 50

44. Air tube over twice as long as wide, its pecten of 19 to 22 teeth _________ 45
Air tube twice as long as wide or less, its pecten of 12 to 14 teeth _______ 48

45, Seales of the comb with the central spinule shorter than the body of the
seale; pecten of the air tube of equal teeth _____._____-____-.._-__1- 46
Seales of the comb with central spinule as long as the body of the seme:
pecten of the air tube longer outwardly___________________.__________- 47

46. Air tube two and one-half times as long as wide; comb scales moderate.

48.

49,

The Atlantic coast salt-marsh mosquito _ Ochlerotatus sollicitans Walker.
Air tube three times as long as wide; comb scales long. In rain puddles,
with a southern distribution _______________ Ochlerotatus mitchella Dyar.

. Air tube pecten reaching to beyond the middle of the tube; lateral comb of

21 scales in nearly three rows ________ Ochlerotatus trivittatus Coquillett.
Air tube pecten not reaching to the middle of the tube; comb of 17 scales
in two imperfect rows. An early spring species.

Ochlerotatus awroides Felt.

Seales of the comb feathered on the sides, with central thorn.
Aédes infirmatus Dyar and Knab.!
Scales of the comb evenly feathered; no central thorn_________________- 49
Air tube one and one-half times as long as wide; pecten teeth broadly ellip-
tical. In puddles along the Atlantic seaboard_ Ochlerotatus damnosus Say.”
Air tube twice as long as wide; pecten teeth narrowly elliptical. An early
SpRINOVSpPeCles see = Ochlerotatus inconspicuus Grossbeck.

. Air tube four times as long as wide; trachez narrow, angled. An early

Spin euspecicsaee= sme | ei se 2s - Ochlerotatus fitchit Felt and Young.
Aum tiube three pimes asslon® as wide or less. -2= 92) ee 51

. Anal plate small; gills very large, sack like, spotted.

Ochlerotatus varipalpus Coquillett.
Anal plate over half encircling the segment ; anal gills moderate or small_ 52

. Comb scales tapered, a single median spinule stouter or larger than the
MCS eee eee ee Mee tl eels ele 59
Comb scales bluntly rounded, the median spinule resembling the others__ 59
. Both of the hair tufts on the front.of the head multiple_-_--___-_________ 54
The lower head tuft single or double (rarely three) _____________________ 56

. Subdorsal prothoracie hairs single. In temporary pools.

Ochlerotatus canadensis Theobald.
Ochlerotatus nivitarsis Coquillett. *

Supaormal prochoracic hairs multiple:=...+- 2+. 3 3212.5 See eee 5D

. Weakly colored ; tufts of ventral brush short-stemmed. In puddles near
the sea along the Atlantic coast _________ Ochlerotatus cantator Coquillett.
Darkly colored ; tufts of the ventral brush long-stemmed. An early spring
species in the Northwest ___-___-_-__- __ Ochlerotatus pullatus Coquillett.
ilo wemheadehardouple. (or triple). 2 28 ee i

ower head hair Single: —2. 4.22 == - = a aT. ea CES eS eens FAO

1 Ochlerotatus confirmatus (in part).
2 Ochlerotatus teeniorhynchus.
’ Imperfectly known,

oO

6

Jomb scales with lateral spinules as long as the apical one. An early spring

SPECIES meee ts SS hie! sts ek eee Aédes grossbeckt Dyar and Knab.!
Comb scales with the lateral spinules very short. An early spring species.
Ochlerotatus pretans Grossbeck.

Apical spinule of the comb scale sharp and distinct An early species in the

Northwest's. 5302 = s S82 ae eee Ochlerotatus astivalis Dyar.
Apical spinule of comb scale not sharply distinct. An early spring species
imyphesNonrtheast.].2 == ase. ==. eee See eee Ochlerotatus subcantans Felt.

Anal gills moderately long. An early spring species in the Northeast.
Ochlerotatus lazarensis Felt.
Anal gills very short, bud-shaped. The Pacific coast salt-marsh mosquito.
Aédes quaylei Dyar and Knab.*

1 Lepidoplatys squamiger (in part).
2 Ochlerotatus lativittatus.

Approved :

JAMES WILSON,
Secretary of Agriculture.

WASHINGTON, D. C., April 27, 1906.

O

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