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Identification Atlas of the Vespidae (Hymenoptera, Aculeata) of the northeastern Nearctic region
CJAI 05, February 19, 2008
doi: 10.3752/cjai.2008.05

Matthias Buck, Stephen A. Marshall, and David K.B. Cheung

Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1


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80. Polistes sp. A
Figs B10.14, 16, 18, 35, 47; C80.1–7.

Polistes sp. A
Polistes sp. A
Polistes sp. A
Polistes sp. A

Taxonomy. This newly discovered, undescribed species belongs in the P. fuscatus-group and was previously confused with P. fuscatus, P. metricus, P. bellicosus and P. carolina (depending on the colour pattern of the individual). Northeastern females key to P. metricus in Richards’ (1978) key, which does not properly separate P. fuscatus from P. metricus. The most remarkable diagnostic character of sp. A is the (usual) absence of the pronotal fovea, a structure that occurs in every other species of the P. fuscatus-group. Otherwise, species without a pronotal fovea occur only in some Neotropical species of the subgenera Aphanilopterus and Epicnemius as well as the Old World/Australasian subgenus Polistella.

Species recognition. No other northeastern species of the P. fuscatus-group is better characterized by morphology than sp. A (some other species can only be separated on colouration). These characters include (see key): pronotal fovea usually absent or minute (see below); propodeal orifice narrowed dorsally; female flagellum more extensively hairy than in other species; micropunctures of mesosoma and clypeus smaller than usual, the integument therefore more shining (‘greasy’ in appearance); eyes with sparse, minute hairs, and tergum 1 evenly and quite strongly convex (less convex in some males).

Description. Fore wing length 13.5–15.5 mm (♀♀), 12.5–15.5 mm (♂♂). Pronotal fovea variable, on average better developed in males than in females (Table 3).

Table 3. Development of pronotal fovea in Polistes sp. A
minute, shallow
fairly large and deep
13 (57%)
10 (43%)
4 (18%)
10 (46%)
8 (36%)
17 (38%)
20 (44%)
8 (18%)

Note: One female could not be scored due to heavy greasy/oily deposit on cuticle.

Female head largely ferruginous; black are large but deeply incised ocellar spot, some facial sutures, sometimes narrow band connecting antennal bases, occiput above foramen (except for latter black markings absent in one specimen each from Virginia and Florida); yellow markings vary from absent to well-developed (some specimens from Illinois and Missouri) and then include: chevron-shaped spot along clypeal margin, part of mandibles, transverse stripes above antennal bases (sometimes fused medially), and inner orbits from level of antennal bases to clypeal margin; facial markings often suffused with orange. Antenna ferruginous with black to dark brown dorsal surface (basal half of scape sometimes ferruginous). Mesosoma largely ferruginous; black as follows: spot in front of pronotal carina (sometimes covering most of anterior face of pronotum), sometimes dorsal surface of pronotum, scutum except usually two pairs of ferruginous stripes (in southern specimens scutum largely ferruginous), sometimes spot(s) in centre of scutellum (one specimen), pleural sutures, rarely most of metapleuron, sutures between scutum and propodeum, more or less extensive ventral areas of mesosoma, central stripe and sometimes lateral stripes of propodeum (stripes narrow to very broad); yellow are pronotal carina and ventral pronotal spots (usually poorly developed, sometimes connected), dorsal mesopleural spot (usually absent), small spots immediately above mid and hind coxae, small posterodorsal spot of metapleuron (usually absent), small paired scutellar spots (usually absent), paired metanotal spots (sometimes absent), relatively short and narrow propodeal stripes (usually absent), propodeal valvula. Metasoma predominantly black to dark brown, with ferruginous spots at least on terga 1 and 2 (one specimen each from Virginia and Florida with entirely ferruginous metasoma); dark colour of posterior segments often becoming gradually paler posteriorly; yellow are apical fascia of tergum 1 (usually narrow and inconspicuous, often widely interrupted medially, rarely absent) and in midwestern specimens usually more or less interrupted fasciae on terga 2 and 3, lateral spots on tergum 4 and sterna 2–4. Legs largely ferruginous, with the following black to dark brown: parts of coxae (especially mid and hind coxa), fore femur sometimes posteriorly, mid and hind femur usually ventrally, dorsal surface of tibia (often absent on fore tibia, most extensive on hind tibia); legs nearly entirely ferruginous in one specimen from Virginia; yellow are lateral to posterolateral stripes on all coxae (only midwestern and southern specimens), apex of femora and base of tibiae (sometimes inconspicuous; sometimes basal 2/5 of mid and hind tibiae dorsally), tarsi more or less yellowish, especially basitarsi. Males known only from specimens collected in Maryland (expected to be darker and with less developed yellow markings than specimens from western or southern part of range). Face largely yellow up to eye emargination; eye emargination, central part of frons between and below antennae, and dorsomedial part of clypeus slightly to strongly suffused with ferruginous, black markings include interantennal tubercle, often vertical stripes between antennal bases and dorsal margin of clypeus, and sometimes dorsomedial spot on clypeus. Antennae ferruginous with black dorsal surface. Mesosoma usually largely black with the following ferruginous markings: spot on lateral surface of pronotum frequently, stripes on scutum and propodeum rarely, margins of scutellum and metanotum, rarely their disks as well, dorsal mesopleural spot often, spots on lower mesopleuron and metapleuron rarely; yellow mesosomal markings unusually restricted, similar to female and sometimes completely absent; venter of mesopleuron often with small yellow spots behind fore coxae. Metasoma largely black; ferruginous spots usually present on tergum 2 (rarely covering most of tergum), sometimes also present on terga 1 and 3 and/or sterna 1 and 2, rarely posterior metasomal segments in part more or less dark ferruginous; yellow markings very restricted: apical fascia of tergum 1 usually present but often indistinct and reduced to small lateral spots; terga 2 and 3 rarely with interrupted fasciae as well; apical fascia usually present but usually interrupted on sternum 3, often on 4, rarely on 2. Leg colouration as in female but with the following additional yellow markings: pale yellow spot on fore coxa (sometimes restricted to medial surface) and almost always on mid coxa; yellow anterior stripes on fore femur, almost always on mid femur and usually on hind femur, size of spot decreasing from former to latter, on hind femur often only a small spot near base; dorsal surface of tibiae with yellow stripe (sometimes restricted to basal half on hind tibia); yellow markings of femora and tibiae often more or less suffused with orange, especially towards the edges.

Distribution. Not known from Canada. Apparently widespread but rare in eastern U.S.; so far recorded (22 ♂♂, 24 ♀♀) from DE, MD, VA, NC, SC, FL, IL, and MO.

Biology. Unknown.


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Polistes sp. A Polistes sp. A Polistes sp. A Polistes sp. A Polistes sp. A Polistes sp. A Polistes sp. A Polistes metricus