Adult male identified by Townes as C. atrella, to which the male terminalia shows similarity.
Pupa No pupae were present in our samples, but some pupal characters were visible from a late prepupa. The spur has about three spines, progessively along the outer edge in the available specimen.
Larva a small to medium sized bathophilus-type, length about 13.5 mm. Gular region dark, frontoclypeus pale. Mentum (Fig. d) with somewhat rounded teeth; centre tooth broad and relatively tall, side teeth little more than notches (type I-II); fourth laterals slightly reduced to just above the fifth laterals (type I-II); sixth laterals lower compared to the fourth laterals. Ventromental plates (Fig. e) with a smooth anterior margin and about 38 Ð 42 striae. Premandible (Fig. a) with inner tooth 2 Ð 3 times wider than outer tooth. Pecten epipharyngis (Fig. c) with about 13 - 15 irregular teeth. Antennal ratio 1.99 Ð 2.33; basal segment about 2.3 Ð 3.2 times longer than wide (Fig. b). Mandible (Fig. f) with third inner tooth relatively well developed and almost completely separated (type II-III), with about 12 Ð 16 striae. Anal tubules short and rounded, only about as long as wide.
Cytology: 4 pairs of chromosomes with the thummi arm combination AB, CD, EF, G. Keyl pattern difficult to recognise particularly since 4 identifying bands of arm B are away from the centromere. Arm G may be fully paired, but it usually unpaired towards the sub-terminal nucleolus; a central Balbiani ring and one near the other end. A nucleolus is sometimes developed about 1/3 from distal end of arm B. Polymorphic in arms A, C, D, E F and G: polymorphism in C is small and terminal; apparently 3 sequences in arm D, one of which is complex and appears to involve 2 non-overlapping inversions.
qutA1:
qutA2:
qutB1: Characteristic bands (24-27) towards the middle of the arm; nucleolus, when present, immediately distal of these bands.
qutC1:
qutD1:
qutE1: possibly 1 - 2, 8 - 3, 10 - 13
qutE2: possibly 1 - 2, 8 , 10 - 13
qutF1:
qutF2:
Found: Connecticut - South Cove, Old Saybrook, Middlesex Co.
Massachusetts - East Harbor (Truro), Cape Cod National Seashore, Barnstable Co.
Tidal mud flats.
This species was identified as C. atrella by Townes and Roback (Hitchcock & Anderson, 1968), but is cytologically quite distinct from other C. atrella populations. In general the cytology suggests it is a member of the C. decorus-group, with similarities to C. decorus (Sp. 3a).
The biology was described by Anderson & Hitchcock (1968).