Coccus ulmi

Williams, D. J. & Z. - Q, 2007, Carl Linnaeus and his scale insects (Hemiptera: Coccoidea) *, Zootaxa 1668 (1), pp. 427-490 : 459-461

Coccus ulmi (Family Diaspididae ) [now known as Lepidosaphes ulmi (L.)]

( Figure 11 )

Description

Scale cover of adult female, oyster-shell shaped, slightly convex, usually dark brown, exuviae of previous instars yellow to brown, situated at anterior end. Adult female white with pygidium becoming sclerotized. Male scale cover much smaller and similar in shape to that of adult female.

Adult female on microscope slide, elongate pyriform, membranous except for rounded pygidium.

Abdominal segments well lobed laterally with lateral tubercles or blunt spurs on margins of abdominal seg- ments I and II and sometimes on segment III. Legs absent. Antennae tubercle-like, each with 2 or 3 setae. Anal opening dorsal, situated near base of pygidium. Anterior spiracles each with an associated group of 3–8 pores each with 3 loculi. Posterior spiracles devoid of pores. Lobes numbering 2 definite pairs. Median lobes projecting at apex of pygidium, separated by about half width of a lobe, each lobe usually notched at each side and with converging paraphyses. Second lobes bilobed, each lobe rounded. Gland spines each with a minute duct, normally in pairs between median lobes, between median and second lobes, lateral to second lobes and on margins of abdominal segment VI, giving way to smaller and more numerous gland spines forwards to abdominal segment I or metathorax. Marginal macroducts absent between median lobes, singly between each median and second lobe, in pairs lateral to second lobes and on abdominal segment V, and singly on abdominal segment IV. Much smaller dorsal macroducts present in small groups anterior to median lobes and in long groups from margins to medial areas usually as far forward as about abdominal segment I, ducts more numerous in marginal areas and extending marginally to mesothorax. On venter, small ducts present, often in clusters on margins of prothorax to a few on abdominal segment III, extending almost to medial areas of mesothorax and abdominal segment I. Microducts present on venter of head and in submedial areas of abdominal segments II–V. Cicatrices often located on any of abdominal segments I–VI.

Comments

There are no specimens of this species in Linnaeus’ collection. Linnaeus (1758) included references to two completely different species of scale insects described by Réaumur (1740). Plates 2 and 7 in Réaumur cited by Linnaeus do not refer to Coccus ulmi as we now know it but there can be no doubt about the identity of the insect cited as figs 5–7 on Plate 5 which clearly show aspects of an armoured scale insect. Linnaeus (1761) added no references to the entry under Coccus ulmi but Linnaeus must have realised his mistake because in his 12th edition of Systema Naturae ( Linnaeus, 1767) he cited the work of Geoffroy [Geoff. paris.512. n. 7 (q.v.)] describing the same armoured scale insect as Réaumur had shown in his figs 5–7 on Plate 5. The other scale insect referred to in Réaumur (1740) was later described as Coccus spurius by Modeer (1778), now known as Eriococcus spurius (Modeer) (family Eriococcidae ).

Coccus ulmi L. has many synonyms and combinations. It was first included in the genus Lepidosaphes Shimer by Fernald (1903), as L. ulmi (L.), where it has remained. The species is common throughout the Holarctic Region and is known mainly in temperate areas in other regions on many plant species, mostly on woody tissue. For full synonymy, distribution and host plant range see Miller & Gimpel (2007b). Furthermore, the species has been described and illustrated well in Newstead (1901), Ferris (1936), Balachowsky (1954), Danzig (1980), Kosztarab & Kozár (1985) and Miller & Davidson (2005). The accompanying illustration is taken from Ferris (1936) first published in Microentomology Volume 1.

Figures

FIGURE 11. Coccus ulmi L. Adult female. (Now Lepidosaphes ulmi (L.)).