Micrococcidae Silvestri 1939

MICROCOCCIDAE Silvestri 1939

Micrococcus Leonardi 1907, 135. Type species: Micrococcus silvestrii Leonardi by subsequent designation Sanderson 1909: 42.

Introduction. This family was revised by Miller and Williams (1995). It currently contains 2 genera (Micrococcus Leonardi (9 species) and Molluscococcus Miller & Williams (1 species)). Mi. bodenheimera Bytinski-Salz is a pest of Poaceae to which it appears to be almost exclusively restricted. Its relationships within the Coccomorpha were described by Miller and Williams as being an enigma. Miller and Williams did a morphological cladistic analysis based on adult female morphology and concluded that the family was closest to the Coccidae and Aclerdidae rather than to the Eriococcidae and Pseudococcidae, as sometimes considered (Ferris, 1957a; Silvestri 1939). The only molecular study that has included a member of the Micrococcidae (e.g., Micrococcus sp. from Italy) is that of T. Kondo & L.G Cook (unpublished data based on a Bayesian phylogenetic analysis of the family Coccidae using DNA sequences based on 18S, 28S and partial CO1 data), who found that the Microccoidae fell within the Coccidae. The only description of an adult male is by Miller and Williams (1995). The following diagnosis is based entirely on Miller and Williams’ (1995) study of the male of Mi. bodenheimera (Fig. 77)

Family diagnosis based on the adult male of Micrococcus bodenheimera (Fig. 77). Apterous, therefore thorax membranous, without wings or hamulohalteres and associated structures. Less than 2 mm long. Body with hs setae only, each short (less than 25 µm long ); simple (discoidal) convex pores frequent throughout, particularly near margin; bilocular microducts of 2 sizes, smaller pores occasional near dorsopleural setae, larger pores only on venter, most abundant on thorax. Incipient mouthparts possibly present. Antennae 3 segmented, with only hs setae; capitate setae and antennal bristles absent. Thorax: spiracles normal; with well developed legs; trochanter sensilla in a line; femur unusually broad for a male scale insect; tibia and tarsus fused; tarsal digitules capitate; claw digitules capitate. Abdomen with some sclerotisation ventrally on posterior margins of segments. Caudal extensions absent (but with an “oval process” on segment VIII). Glandular pouches absent. Abdominal sternite fused with penial sheath. Anal ring present dorsally on segment IX. Penial sheath short and triangular, about twice as long as wide. Aedeagus about as long as penial sheath, blunt.

Comment. Because the adult male of this species is apterous, its taxonomic relationships to other Coccomorpha families is bound to be difficult to establish. However, the trochanter sensilla in a line strongly suggests that this family is not close to the Pseudococcidae or acanthococcine Eriococcidae, whilst the presence of simple convex pores and the possible fusion of abdominal segment VIII to the penial sheath suggests a possible closeness to the Aclerdidae.