Rhizoecus cacticans

Adult male. Body very small, total length about 840 µm, greatest width about 250 µm. Antennae 10-segmented, rather long, much more than half total body length; most flagellar segments bottle-shaped, narrowing abruptly about 2/3rds along length to form a narrow neck about 8 µm wide; segments III and IV broadest distally, segments V–IX bottle-shaped; approximate number of setae per segment: III 5–8 fleshy setae + 5 hair-like setae; VIII & IX 15–18 fleshy setae, 0 or 1 hair-like seta + 1 short antennal bristle, and X 17–20 setae + 3 antennal bristles. Head with 8 or 9 pairs of hair-like dorsal head setae distributed along full length of head; ventral head setae 4 or 5 pairs, longest about 15–17 µm long. Prothorax with a slight narrowing between head and prothorax; prosternum with 2 pairs of loculate pores in position of prosternal setae and a pair of loculate pores + simple pores in position of anteprosternal setae. Mesothoracic spiracle width of peritreme about 12 µm; metathoracic spiracle width of peritreme about 12–13 µm, with 1 associated loculate pore. Legs: tibia III 70–72 µm long (ratio of length of tibia III to length of tarsus III 1:0.44); tibia III with 16–19 setae, mainly hair-like, becoming spur-like distally; tarsal digitules represented by a pair of long, possibly capitate, setae subequal to length of claw; each trochanter with 3 pairs of roundly oval sensoria and with strong, sclerotised Y-shaped ridges. Abdomen segments I–VIII: setae present in a single line around segments I–VII, not apparently divided into dorsal, pleural and ventral setae, with about 24 hair-like setae around each segment; tergite VIII with 1 pair of hair-like dorsal abdominal setae medially (+ 2 or 3 loculate pores on each side). Genital segment: penial sheath large and bulbous, almost as broad as abdominal segment VIII ventrally, length from anterior margin to apex about 155–165 µm, width at widest point 105–110 µm; ventrally with a broad slit-like opening through which aedeagus emerges, borders of opening quite heavily sclerotised, without setae; aedeagus strongly curved, perhaps 100 µm long, with parallel sides when viewed dorsally, widening at both ends, distal end rather shovel-like; anteriorly, aedeagus bends ventrally and fuses with a short sclerotised basal rod.

Literature