 
*COMMENT ~ Character notes. 
 
*CHARACTER NOTES 
#1. ~ (alternatively) is here used to indicate sometimes not
unreasonably included in or reduced to. 
#3. Length measured in normal posture (e.g., without tilting up the head). 
#5. Pronotum: the single, dorsal sclerite of the prothorax; the latter
being the major part of the beetles thorax which is visible from above. 
#6. Prothorax: the first (anterior) segment of the (three-segmented)
thorax. In beetles this is usually relatively large, forming with the head
a conspicuous, independently movable fore-body. It is composed of a
single dorso-lateral sclerite, the pronotum, a ventral prosternum, and
lateral proepisterna, and bears the front pair of legs.
\par{}Mesothorax and (larger) Metathorax: the second and third thoracic
segments. These are fused together, constituting the pterothorax, which
bears the elytra, (hind-)wings and mid- and hind-legs. \par{}Notopleural
suture: a groove in the side of the prothorax (q.v.), separating the
prosternum (q.v.) from the pronotum (q.v.). . 
#7. Prothorax: the first (anterior) segment of the (three-segmented)
thorax. In beetles this is usually relatively large, forming with the head
a conspicuous, independently movable fore-body. It is composed of a
single dorso-lateral sclerite, the pronotum, a ventral prosternum, and
lateral proepisterna, and bears the front pair of legs.
\par{}Mesothorax and (larger) Metathorax: the second and third thoracic
segments. These are fused together, constituting the pterothorax, which
bears the elytra, (hind-)wings and mid- and hind-legs. \par{}Notopleural
suture: a groove in the side of the prothorax (q.v.), separating the
prosternum (q.v.) from the pronotum (q.v.). 
#9. It is safest, and still potentially useful, to bracket the
possibilities by entering two or more states of this rather subjective
character. 
#15. States 1/2-3 should more or less correspond with Lawrence et al.,
body evenly curved/not evenly curved. 
#26. Rostrum: a marked, rigid elongation of the front of the head (frons
and vertex), on which the antennae are carried forward and which bears the
(biting/chewing) mouthparts at its tip. This modification, characteristic
of the curculionid families (weevils), is utilized by the females to bore
holes in plant material (leaves, stems, fruits, bark, etc.) in which the
eggs are deposited; but details of its significance for males and in
relation to the adults feeding habits are elusive. The second character
image provides a detailed comparison with a non-rostrate form. 
#27. Prognathous (in this context): having the mandibles projecting and
clearly visible when the beetle is viewed from above. 
#36. Ocelli: simple eyes, additional to and located between or behind the
compound eyes. 
#37. Ocelli: simple eyes, additional to and located between or behind the
compound eyes. 
#43. Mandibular prostheca: a membranous (sometimes partly hardened),
usually setose appendage borne on the basal part of the internal ridge of
the mandible, distal to its grinding part (or mola). 
#46. Cf. Lawrence \i{}et al\i0{}.: The galea or outer lobe is always
laterad of the lacinia or inner lobe. Either the galea or lacinia or both
may be reduced in state 1 maxillae, and the lacinia may no more than a
slight expansion of the stipes. In some doubtful cases, the maxilla has
been coded as 1/2. In state 2 maxillae, the single lobe may represent a
galea, a lacinia or a fusion product of these. A state 3 maxilla may appear
to consist of a palp only. 
#48-49. The maxillae and their palps are borne under (posteriorly to) the
mandibles, between the upper (labrum) and lower (labium) lips. The
(1-)4(-7)-segmented maxillary palps are to be distinguished from the
(1-)2(-4)-segmented labial palps, which are located posteriorly to them. 
#52-65:67. Antennae of beetles nearly always have more than three segments
(usually 7-11). The palps, with which they might otherwise be may be
confused, usually have (1-)3 segments (labial palps) or (2-)4(-5) segments
(maxillary palps). 
#66. Frons (of insects): the upper front part of the head. \par{}Antennae
of beetles nearly always have more than three segments (usually 7-11). The
palps, with which they might be might otherwise be confused, usually have
(1-)3 segments (labial palps) or (2-)4(-5) segments (maxillary palps). 
#69-70:74-77. Prothorax: the first (anterior) segment of the
(three-segmented) thorax. In beetles this is usually relatively large,
forming with the head a conspicuous, independently movable fore-body. It
is composed of a single dorso-lateral sclerite, the pronotum, a ventral
prosternum, and lateral proepisterna, and bears the front pair of legs.
\par{}Mesothorax and (larger) Metathorax: the second and third thoracic
segments. These are fused together, constituting the pterothorax, which
bears the elytra, (hind-)wings and mid- and hind-legs. \par{}Notopleural
suture: a groove in the side of the prothorax (q.v.), separating the
prosternum (q.v.) from the pronotum (q.v.). 
#87. Metaventrite' (often but unsatisfactorily called the metasternum:
the main ventral sclerite of the metathorax. \par{}Sclerites: the
conspicuously hardened (scerotised) regions of the segments. Those of
adjoining segments may be fused (disguising the segmentation), or separated
by zones of membranous cuticle (in flexible parts of the body). 
#90. The beetle leg exhibits six primary segments, viz., coxa, trochanter,
femur, tarsus, and the terminal pretarsus. \par{}1. Coxa: the short
first segment, which usually articulates proximally with the abdomen, and
distally with the trochanter. \par{}(Coxal cavity: a cavity in the thorax
into which the coxa fits.) \par{}2. Trochanter: the short second segment,
between coxa and femur, which in beetles freely articulates with the former
but is firmly attached to the latter. \par{}3. Femur: the third leg
segment, articulating distally with the tibia. This is usually the stoutest
and strongest segment, and is sometimes the longest. It sometimes bears
long spines, but never exhibits movable spurs, and is enlarged in the hind
legs of species that jump. \par{}4. Tibia: the fourth leg segment,
articulating distally with the tarsus. Tibiae are usually expanded towards
their apices, which bear combs of spines, two of which are enlarged,
articulated, and known as spurs. The fore tibiae are often expanded and
toothed on the outer side, associated with digging. \par{}5. Tarsus: the
fifth primary segment of the beetle leg, which articulates proximally with
the tibia, and distally with the pretarsus, and is usually itself
resolvable into (2-)4-5 movable segments (tarsomeres). \par{}6.
Pretarsus: the terminal leg component, which usually comprises paired
claws and the median empodium. 
#104. This character appears to be taxonomically meaningful, but apparently
cannot be applied reliably for identifying dead specimens. \par{}The beetle
leg exhibits six primary segments, viz., coxa, trochanter, femur, tarsus,
and the terminal pretarsus. \par{}1. Coxa: the short first segment,
which usually articulates proximally with the abdomen, and distally with
the trochanter. \par{}(Coxal cavity: a cavity in the thorax into which
the coxa fits.) \par{}2. Trochanter: the short second segment, between
coxa and femur, which in beetles freely articulates with the former but is
firmly attached to the latter. \par{}3. Femur: the third leg segment,
articulating distally with the tibia. This is usually the stoutest and
strongest segment, and is sometimes the longest. It sometimes bears long
spines, but never exhibits movable spurs, and is enlarged in the hind legs
of species that jump. \par{}4. Tibia: the fourth leg segment,
articulating distally with the tarsus. Tibiae are usually expanded towards
their apices, which bear combs of spines, two of which are enlarged,
articulated, and known as spurs. The fore tibiae are often expanded and
toothed on the outer side, associated with digging. \par{}5. Tarsus: the
fifth primary segment of the beetle leg, which articulates proximally with
the tibia, and distally with the pretarsus, and is usually itself
resolvable into (2-)4-5 movable segments (tarsomeres). \par{}6.
Pretarsus: the terminal leg component, which usually comprises paired
claws and the median empodium. 
#106:110-111:113-116:118-121:123-125. The beetle leg exhibits six primary
segments, viz., coxa, trochanter, femur, tarsus, and the terminal
pretarsus. \par{}1. Coxa: the short first segment, which usually
articulates proximally with the abdomen, and distally with the trochanter.
\par{}(Coxal cavity: a cavity in the thorax into which the coxa fits.)
\par{}2. Trochanter: the short second segment, between coxa and femur,
which in beetles freely articulates with the former but is firmly attached
to the latter. \par{}3. Femur: the third leg segment, articulating
distally with the tibia. This is usually the stoutest and strongest
segment, and is sometimes the longest. It sometimes bears long spines, but
never exhibits movable spurs, and is enlarged in the hind legs of species
that jump. \par{}4. Tibia: the fourth leg segment, articulating distally
with the tarsus. Tibiae are usually expanded towards their apices, which
bear combs of spines, two of which are enlarged, articulated, and known as
spurs. The fore tibiae are often expanded and toothed on the outer side,
associated with digging. \par{}5. Tarsus: the fifth primary segment of
the beetle leg, which articulates proximally with the tibia, and distally
with the pretarsus, and is usually itself resolvable into (2-)4-5 movable
segments (tarsomeres). \par{}6. Pretarsus: the terminal leg component,
which usually comprises paired claws and the median empodium. 
#126. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings. 
#127. Measurements made in the resting position, with the elytra closed.
The length of the elytra is measured from the base of the scutellum (or
mid-posterior edge of the pronotum if the scutellum is concealed) to the
conjoined elytral apices or to an imaginary line joining the separated
elytral apices. The elytral width is the greatest combined width or, when
the elytra are widely separated their tips, the length of the longest line
joining their two outside edges. 
#128. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings. 
#129. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings. 
#130. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings.
\par{}Abdominal tergite: the sclerotised dorsal region (sclerite, q.v.)
of a visible body segment. Of the abdomen, usually equivalent to segment.
\par{}Abdominal ventrite: the sclerotised ventral region (sclerite,
q.v.) of a visible abdominal segment. The number of ventrites is often
fewer than the number of true segments. \par{}Abdominal sternite: the
sclerotised ventral region (sclerite, q.v.) of an abdominal segment,
whether visible or not. The number of sternites corresponds with the number
of segments. 
#131. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings.
\par{}Abdominal tergite: the sclerotised dorsal region (sclerite, q.v.)
of a visible body segment. Of the abdomen, usually equivalent to segment.
\par{}Pygidium: the terminal (tail-end) exposed and sclerotised abdominal
tergite. It may be either tergite 7 or 8. 
#132. Pygidium: the last (i.e., the eighth) visible abdominal tergite in
Coleoptera. This character seems to provide the only absolute distinction
between \i{}Aphodiidae\i0{} and assorted other Scarabaeidae sensu lato. Cf.
Britton (1970). 
#133. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings. 
#134. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings. 
#135. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings. 
#136. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings. 
#137. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings. 
#138. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings. 
#139. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings. 
#142. Scutellary striole: a short stria or row of punctures situated
laterally to the scutellum and not extending very far posteriorly. 
#143. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings.
\par{}Epipleuron: an infolding or incurving of the costa of the elytron
(i.e., its leading edge, when the elytra are opened), which usually fits
against the sides of the abdomen when the elytra are closed. 
#144. Elytra: paired organs representing the mesothoracic wings, which
when closed usually (but not always) meet along the median line, and
constitute a hardened cover for the beetle's hind-wings and abdomen. They
are usually held open in flight, allowing free movement of the hind-wings. 
#145-148. The metathoracic wings of beetles, when functional for flying,
are usually longer than the elytra (q.v.), and are normally folded and
stored beneath the elytra when the insect is not flying. Not uncommonly
(especially island and montane forms), however, they are more or less
atrophied. 
#152. \par{}Abdominal tergite: the sclerotised dorsal region (sclerite,
q.v.) of a visible body segment. Usually, 8 tergites (representing 10
segments) can be counted on the upper surface of the abdomen: segment 9 is
the much modified genital segment, which is hidden within the body, and
segment 10 is greatly reduced. The visible tail-end tergite represents
segment 8, and is called the pygidium. \par{}Abdominal ventrite: the
sclerotised ventral region (sclerite, q.v.) of a visible abdominal
segment. The number of ventrites is often fewer than the number of true
segments. \par{}Abdominal sternite: the sclerotised ventral region
(sclerite, q.v.) of an abdominal segment, whether visible or not. The
number of sternites corresponds with the number of segments. 
#154-156. \par{}Abdominal ventrite: the sclerotised ventral region
(sclerite, q.v.) of a visible abdominal segment. The number of ventrites
is often fewer than the number of true segments. \par{}Abdominal
sternite: the sclerotised ventral region (sclerite, q.v.) of an
abdominal segment, whether visible or not. The number of sternites
corresponds with the number of segments. 
#158. Entomologists have made extensive taxonomic use of variations in male
genitalia for classificatory purposes, and the groupings represented by
this character seem reliably indicative of coleopteran taxonomic
relationships. However, in the absence of comparative data for the
anatomical details, which are in any case rather inaccessible and
applicable only to males, these are of little use for conducting
identifications. \par{}Cf. Lawrence \i{}et al.\i0{} (1999). Aedeagus
refers here to the external genitalia, including the intromittent organ
(penis, representing two fused valves) and associated structures
(phallobase and parameres, or tegmen) but excluding modifications of apical
or pregenital abdominal segments. Some coleopterists restrict it to the
penis combined with phallobase and parameres or tegmen, while others refer
to the phallobase as fused gonocoxites, the parameres as gonostyli, and the
two together as gonoforceps. See Crowson (1984), D'Hotman and Scholtz
(1990), Gilbert (1952), Iablokoff-Khnzorian (1980), Jeannel (1955), Jeannel
and Paulian (1944), Lindroth (1957), Matsuda (1976), Nichols (1989), Tuxen
(1970) and Wood (1952). 
#159. \par{}For purposes of identification, the term water beetle here
includes assorted forms associated with wet habitats, in addition to true
aquatics. \par{}Aquatic: living in water, with convincingly observed
adaptations for respiring when submerged. Sub-aquatic: inhabiting wet
places and apparently or supposedly surviving inundation, but sometimes not
conspicuously adapted for respiring submerged. Assignment to these
categories is sometimes unsatisfactory, because survival strategies in
assorted sub-aquatic families are either unknown, or are not detailed in
the literature seen; and assignments are further complicated by (e.g.)
\i{}Hydraenidae\i0{}, in which the adults are genuinely aquatic but the
larvae are easily drowned, and by \i{}Scirtidae\i0{}, which combine
terrestrial adults with aquatic larvae. The huge families
\i{}Chrysomelidae\i0{} and \i{}Curculionidae\i0{} are here regarded as
terrestrial, although adults associated with helophytic plants are
sometimes encountered floating or struggling in water. 
#162. \par{}Plastron: in the present context, a pile of fine hydrofuge
hairs on the ventral surface of many aquatic beetles, in which air is
collected and stored to supply oxygen for respiration when they are
submerged. Air transferred from the plastron to the water-tight space under
the elytra is respired via the terminal pair of abdominal spiracles. The
plastron, which is often conspicuous as a bubble on the underside of the
submerged insect, is a characteristic feature of hydrophilid beetles, and
distinguishes them from dytiscids. The latter also store air under the
elytra, but replenish it directly from the rear. 
#164. \par{}Plastron: in the present context, a pile of fine hydrofuge
hairs on the ventral surface of many aquatic beetles, in which air is
collected and stored to supply oxygen for respiration when they are
submerged. Air transferred from the plastron to the water-tight space under
the elytra is respired via the terminal pair of abdominal spiracles. The
plastron, which is often conspicuous as a bubble on the underside of the
submerged insect, is a characteristic feature of hydrophilid beetles, and
distinguishes them from dytiscids. The latter also store air under the
elytra, but replenish it directly from the rear. 
#165:167. The compiled data are very unsatisfactory, given the lack of
unambiguous records of what adult beetles (as distinct from the larvae)
actually consume and digest: even the best source of information (Lawrence
et al., 1999) offers only non-comparative generalizations. The extent to
which predators are facultatively saprophagous, and vice versa, is
unclear; saprophagous beetles involved with rotting wood and decaying
vegetable matter are probably often mycetophagous; and it seems likely
that all insects with the capacity to imbibe water will digest any
dissolved nutrients. 
#168. Estimates will often over-estimte variation in material from Britain and Ireland,
being derived from world level group measurements given by Lawrence \i{}et
al\i0{} (1999). 
#205:207. The compiled data are very unsatisfactory, given frequent
uncertainty of what is actully consumed (cf. the situation re the adults).
The extent to which predators are facultatively saprophagous, and vice
versa, is unclear; saprophagous larvae involved with rotting wood and
decaying vegetable matter are probably often mycetophagous; and it seems
likely that all insects with the capacity to imbibe water will digest any
dissolved nutrients. See Lawrence \i{}et al\i0{}., 1999. 
#209. See Unwin (1984), Lawrence \i{}et al\i0{} (1999). 
#211. See Unwin (1984), Lawrence \i{}et al\i0{} (1999). 
#212-213. Estimates of genus and species numbers (derived mainly from
assorted Internet sources) are often unreliable, but they should suffice
for viewing representation in Britain and Ireland in a world context. 
#214-216. From Pope (1977). 
 
