51a (50b). Abdomen with a pair of hooks, usually on anal prolegs, at posterior end and without

long lateral processes (but at times with finger-like gills); tarsi with 1 claw; usually living

in cases (Figs.A-F) [caddisfly larvae]..... A............................................…............…....Trichoptera

51b. Abdomen with 4 hooks at posterior end or none, and with or without long lateral

processes; tarsi with 1-2 claws (Fig.A); not living in cases [beetle larvae].......................

........................................................................................................…........................... Coleoptera......152

52a (44b). Mouthparts usually withdrawn into head and not obvious; abdomen with stylelike

appendages on some segments or with a forked appendage near end of abdomen; usually

<7 mm long....................................................................................................…................….....................53

52b. Mouthparts usually distinct, mandibulate or haustellate (= for sucking); abdomen without

appendages as described previously; size variable...................................................…….........…........54

53a (52a). Antennae long, with many segments; abdomen with at least 9 segments and with

stylelike appendages on ventral side of some segments; without a forked appendage near

end of abdomen, but with well developed cerci (Figs.A-C) ... A...............…….................Diplura

53b. Antennae short, with 6 or less segments; abdomen with 6 or less segments and usually with

a forked appendage near posterior end (Figs.A-G) [springtails] ………………….........…Collembola

54a (52b). Body larviform ( = shaped like a worm or larva), thorax and abdomen not

differentiated; compound eyes present [larviform beetles]……......……… Coleoptera…......152

54b. Body shape variable, but if larviform, then without compound eyes.................................…….........55

55a (54b). Compound eyes usually present; body shape variable, but usually not worm-like;

wing pads often present [adults & nymphs]...................................................................................56

55b. Compound eyes and wing pads absent, body usually worm-like in shape [larvae].....…..…..........65

56a (55a). Tarsi with 5 segments...................................................................................…….............................57

56b. Tarsi with 4 or less segments..................................................................................….….........................59

57a (56a). Mouthparts prolonged ventrally into a snout-like process (Fig.A); body somewhat A

cylindrical and usually <15 mm long (Fig.A) [wingless scorpionflies].......…................. Mecoptera

57b. Mouthparts not as previously described; body shape and size variable..............….........................58

58a (57b). Antennae with 5 segments; Texas (some && twisted-winged parasitoids;..

Mengeidae].........................................................................................Strepsiptera.….....................217

58b. Antennae with >5 segments; widely distributed (Figs.A-G) [rock crawlers, walking A

sticks & some cockroaches]......................................................................…........................Orthoptera

59a (56b). Cerci like forceps; tarsi with 3 segments.................................................……...............................60

59b. Cerci absent or, if present, not like forceps; tarsi variable...................................…….........................61

60a (59a). Antennae more than 1/2 as long as body; cerci short; western U.S.A. [Timemidae]

…………................................................................................................…..........................Orthoptera

60b. Antennae usually less than 1/2 as long as body; cerci long (Fig.A); widely distributed A

[earwigs]………………………………………………………………………...............…..… Dermaptera

61a (59b). Tarsi with 3 segments, basal segment of front tarsi enlarged (Figs.A-B)

[webspinners]...........................................................................................…..........................Embioptera

61b. Tarsi with 2-4 segments, basal segment of front tarsi not enlarged.....................…........…...............62

62a (61b). Appearance like grasshoppers, with hind legs enlarged and fitted for jumping; length

usually >15 mm (Figs.A-E) [grasshoppers]… A……...…………………............… Orthoptera

62b. Not like grasshoppers, hind legs usually not as previously described; length <10 mm ….....…....63

63a (62b). Tarsi with 4 segments; pale, soft bodies, wood- or ground-inhabiting insects A

(Figs.A-E) [termites]................................................................................................................Isoptera

63b. Tarsi with 2-3 segments; color and habits variable..................................................…............…..........64

64a (63b). Cerci present, 1 segmented, and terminating in a long bristle; antennae with 9

segments and moniliform (Figs.A-C); compound eyes and ocelli absent (= simple

eyes); tarsi with 2 segments.... A...............................................................................…......Zoraptera

64b. Cerci absent; antennae with 13 or more segments and usually hair-like (Fig.A);

compound eyes and 3 ocelli usually present; tarsi with 2-3 segments [psocids]...............

.........................................................................................................................................…......Psocoptera

65a (55b). Ventral prolegs (= fleshy abdominal legs) present on 2 or more abdominal segments

(Figs.A-B)..... A.....................................................................................…….................................66

65b. Abdominal prolegs absent or on terminal segment only.........................................…….....................68

66a (65a). Have 5 pairs prolegs (on abdominal segments 3-6 & 10) or fewer (Fig. A), the prolegs with

tiny hooks (crochets); several (usually 6) ocelli on each side of head [caterpillars]

.............................................................................................................................. Lepidoptera…….....227

66b. Have 6 or more pairs of abdominal prolegs, the prolegs without crochets; ocelli number

variable ..........................................................................................................................................…….......67

67a (66b). Ocelli, 7 or more, on each side of head; prolegs on segments 1-8 or 3-8, usually faint

pointed structures (Fig.A) [scorpionfly larvae]........ A...............................................Mecoptera

67b. Ocellus (one) on each side of head; prolegs fleshy and not pointed, usually on abdominal

segments 2-8 & 10, sometimes on 2-7 or 2-6 & 10 (Figs.A-B) [sawfly larvae]

................................................................................................................................Hymenoptera.……..118

68a (65b). Mandible and maxilla on each side united to form a sucking jaw that is often long

(Figs.A-B); tarsi with 2 claws; labrum absent or fused with head capsule; maxillary A

palps absent [Planipennia: lacewing & antlion larvae]................................Neuroptera…..........194

68b. Mandibles and maxillae not as previously described; tarsi with 1-2 claws; labrum and

maxillary palps usually present....................................................................................................…….....69

69a (68b). Head and mouthparts prognathous (= directed forward), the head ca. as long along

midventral line as along middorsal line and usually cylindrical or a bit flattened ....…............70

69b. Head and mouthparts hypognathous (= directed ventrally), the head much longer along

middorsal line than along midventral line and usually rounded...........................………...................72

70a (69a). Tarsi with 1 claw [some beetle larvae]..............................................................……......Coleoptera

70b. Tarsi with 2 claws...................................................................................................................……............71

71a (70b). Distinct labrum (= upper lip) and clypeus (= hardened plate on lower face between

frons and labium) present [Raphidiodea: snakefly larvae]...............................Neuroptera.....194

71b. Labrum absent or fused with head capsule [most Adephaga: beetle larvae]..…….....…..Coleoptera

72a (69b). Front legs noticeably smaller than other pairs; middle and hind legs projecting

laterally much more than front legs; a small group of ocelli (usually 3) on each side of head behind

bases of antennae; tarsal claws absent; length <5 mm; usually found in moss

[Boreidae larvae]...........................................................................................…...............….....Mecoptera

72b. Legs not as previously described, front and middle legs ca. same size and position; ocelli

variable; tarsi with 1-3 claws; size and habitat variable.......................................…...........……...........73

73a (72b). Tarsi with 1-2 claws; abdomen usually without caudal filaments; antennae variable

[beetle larvae]............................................................................................................…........Coleoptera

73b. Tarsi usually with 3 claws; abdomen with 2 caudal filaments ca. 1/3rd as long as body (Fig.A);

antennae usually short with 3 segments [triungulin (= active 1st instar) larvae A

of some beetles, Meloidae, and twisted-winged parasitoids]..........................................

.........................................................................Coleoptera.....152 and ................ Strepsiptera…....217

74a (28b). Aquatic [fly larvae]......................................................................................................……......Diptera

74b. Terrestrial or parasitic (not aquatic).....................................................................................…….............75

75a (74b). Sessile, plant feeding; body covered by a scale or waxy substance; mouthparts for

sucking, long and thread-like [female scales]............................................................…...Homoptera

75b. Not the same as previously described..................................................................................……...........76

76a (75b). Head and thorax almost fused, and abdominal segmentation indistinct (Fig.A); A

internal parasitoids of other insects [female twisted-winged parasitoids]...Strepsiptera.....222

76b. Head not fused with thorax, body segmentation distinct; habitat variable...........……....................77

77a (76b). Head distinct, sclerotized, and usually pigmented and exserted...................……....................78

77b. Head indistinct, incompletely or not at all sclerotized, sometimes retracted into thorax…......…...85

78a (77a). Head and mouthparts prognathous (= directed forward), the head ca. as long along

midventral line as along middorsal line and usually cylindrical or slightly flattened..….........79

78b. Head and mouthparts hypognathous (= directed ventrally), the head much longer along

middorsal line than along midventral line and usually rounded.................................….......……......82

79a (78a). Terminal abdominal segment with a pair of short pointed processes; several long

setae on each body segment (Fig.A) [flea larvae]... A.................................…....Siphonaptera

79b. Not exactly as previously described.....................................................................…............…..............80

80a (79b). Labium with a protruding spinneret (= silk-producing structure); antennae arising

from membranous area at bases of mandibles; mandibles well developed, opposable; body

usually slightly flattened; ventral prolegs usually with crochets; mostly leaf miners in

leaves, bark, or fruits [moth larvae]....................................................................Lepidoptera......227

80b. Labium without a spinneret; antennae, if present, arising from head capsule; prolegs

without crochets......................................................................................................................…………...81

81a (80b). Mouthparts distinctly mandibulate, with opposable mandibles; spiracles usually

present on thorax and 8 abdominal segments; body shape variable [beetle larvae].....Coleoptera

81b. Mouthparts as previously described or with mouth hooks somewhat parallel and moving

vertically; spiracles variable, but usually not as previously described; body elongated

[Nematocera & some Brachycera fly larvae]....................................................…….................Diptera

82a (78b). Abdominal segments usually with 1 or more longitudinal folds laterally or

lateroventrally; body C-shaped, scarabaeiform (Fig.A); 1 pair of spiracles on thorax

and usually 8 pairs on abdomen [beetle larvae, white grubs].... A...........……..........Coleoptera

82b. Abdominal segments without longitudinal folds, or if present, then spiracles not as

previously described............................................................................................……...............................83

83a (82b). Head with adfrontal areas (= pair of narrow oblique sclerites on head) (as in

Fig.A); labium with a projecting spinneret; if present, antennae arise from

membranous area at base of mandibles; often 1 or more ocelli (usually 6) on each side of

head; ventral prolegs, if present, with crochets [moth larvae]..……..............................Lepidoptera

83b. Head without adfrontal areas, and labium without a spinneret; antennae and ocelli not as

previously described; prolegs, if present, without crochets......................................….........…..........84

84a (83b). Mandibles not heavily sclerotized and not brush-like; spiracles usually present on

thorax and most abdominal segments, the posterior pair not enlarged; larvae occur in plant tissues

as phytophagous parasites, or in cells constructed by adults [Apocrita]….Hymenoptera.....118

84b. Mandibles usually brush-like; spiracles usually not as previously described-- if present on

several abdominal segments, the posterior pair is much larger than the rest; occur in wet

places, in plant tissues, or as internal parasites (Fig.A) A [fly larvae, mainly Nematocera]

............................................................................................................................…...........................Diptera

85a (77b). Mouthparts mandibulate, with opposable mandibles and maxillae; antennae

usually present [beetle larvae].......................................................................................…....Coleoptera

85b. Mouthparts reduced or modified, with only the mandibles opposable, or with parallel

mouth hooks present; antennae usually absent..................................................................……...........86

86a (85b). Body behind "head" (first body segment) consisting of 13 segments; full grown

larvae usually with a sclerotized ventral plate ("breast bone") located ventrally behind head

[Cecidomyiidae larvae]..............................................................................................................Diptera

86b. Body with fewer segments than previously described; no "breast bone".........................……........87

87a (86b). Mouthparts consist of 1-2 (if 2 then parallel, not opposable) median, dark colored,

down curved mouth hooks [Cyclorrhapha maggots]............................................................Diptera

87b. Mandibles opposable, but at times reduced, without mouth hooks as described previously

[Apocrita larvae].......................................................................................................................Hymenoptera

Major Families of Adult Entomophagous Diptera: (for muscoid flies see Figs C-D wing venation)

88a (8a, 29a & 38b). Antennae moniliform, 6-39 segments, longer than thorax.......……............…..........89

88b. Antennae with 3-4 segments, ring-like segments may be present; antennae shorter than

thorax.. .........................................................................................................................................................94

89a (88a). Costa (= longitudinal wing vein) extends completely around wing, occasionally

weakened behind.................................................................................................................................90

89b. Costa does not reach to or extend only slightly beyond wing tip ..........................................……....92

90a (89a). Mesonotal suture (= dorsal sclerite of mesothorax) transverse, not V-shaped..…..........…....91

90b. Mesonotum with an entire V-shaped suture; females with long sclerotized ovipositor

(Figs.A-B) (larvae are predators of aquatic or semiaquatic arthropods) A

..............................................................................................……...............................(Diptera) Tipulidae

91a (90a). Ocelli present and/or venation reduced; eyes meet above antennae; wing not scaly

(Figs.A-C) A (larvae are predators of Homoptera & mites).…........(Diptera) Cecidomyiidae

91b. Ocelli absent; probosis extends far beyond clypeus; wing venation strong; wing veins and

margin covered with scales, usually also on body (Figs.A-G) (larvae of some species

are predators of aquatic arthropods)..................................................……..........(Diptera) Culicidae

92a (89b). Ocelli absent......................................................................................……..........................................93

92b. Ocelli present; tibiae with apical spurs; discal cell in wing (= enlarged cell in basal or

central part of wing) absent (Figs.A-C) A (larvae spin webs & feed on entrapped

arthropods)......................................................................…...................……..(Diptera) Mycetophilidae

93a (92a). Head rounded behind, mouthparts piercing; metanotum short and rounded, without a

longitudinal groove (Fig.A) A (adults are blood-suckers; larvae are predators) ..............

...................................................................................……….........................(Diptera) Ceratopogonidae

93b. Head flat behind, mouthparts without mandibles, not piercing ;metanotum long, with a

median longitudinal groove (Figs.A-B) (most are predators, one species parasitizes

mayflies)...................................................................………...............................(Diptera) Chironomidae

94a (88b). Empodium (= pad or bristlelike structure at apex of last tarsal segment between the

claws) developed lobelike, the 3 pads almost equal.....................................…..............................95

94b. Empodium hair-like or absent................................................................................…..................…...........99

95a (94a). Third antennal segment compound, composed of ring-like segments...........……..…..............96

95b. Third antennal segment simple, frequently bearing an elongated style or arista...………................97

96a (95a). Tegula (= scale-like structure overlying front wing base) large and conspicuous

female abdomen large (Figs.A-F) A (adults are blood-suckers; larvae are predators of

aquatic arthropods) .................................................................…….......................(Diptera) Tabanidae

96b. Tegula small or vestigial; tibial spurs usually absent (Figs.A-F) (larvae are predators

of arthropods in several habitats).........................................……...............(Diptera) Stratiomyiidae

97a. Tegula small or vestigal............................................…………………….....……......................................98

97b. Tegula large, covering haltere; head very small, positioned low down and composed

almost entirely of compound eyes; body humpbacked (Fig.A) A (parasitoids of spiders)

………………………………………………………………….................……..(Diptera) Acroceridae

98a (97a). Tibiae without apical spurs; wing venation intricate with many veins ending before

wing tip (Figs.A-B) (parasitoids of grasshoppers).... A....…........(Diptera) Nemestrinidae

98b. At least middle tibia with apical spurs; antennae have long terminal style; wing venation

normal, not complex (Figs.A-B) (both adults and larvae are predators of other

arthropods)...........................................................................................................(Diptera) Rhagionidae

99a (94b). Wing with 2 or more submarginal cells (vein R-4+5 forked); 3-4 posterior cells……......….100

99b. Wing with only one submarginal cell or none at all (vein R-4+5 not forked)....………..................106

100a (99a). Front strongly concave at vertex........................................................…..…………...................101

100b. Front not concave between eyes, vertex flat or convex....................................……........................102

---------------

Key continues with <insect3.htm>