Any changes for B- and C-cup sizes are written in brackets. If there is only one figure it applies to all sizes. Bottoms are one-size. Standard abbreviations are used. 

You need:
• 1 hank Butterfly Super 10 (125 g) pure cotton yarn, No. 3401 Orange
• One pair of 4.5 mm needles OR whichever needles you require to produce the tension given below
• One 4.25 mm crochet hook
• Stitch markers
• Tapestry needle
• Clear elastic knitting thread
• 12.5 cm (5 ins) square of swimsuit lining in desired colour (optional)
• Matching thread (optional)

Tension:
20 sts and 26 rows = 10 cm (4 ins) in stocking stitch. Work to exact tension with specified yarn to obtain satisfactory results. TO SAVE TIME, TAKE TIME TO CHECK TENSION.

To make:
BRA CUP (make 2):
With knitting needles, cast on 29(33,37) sts.
Row 1 (right side): Knit.
Row 2: Purl.
*Row 3: K1, sl1, k1, psso, knit to last 3 sts, k2tog, k1. 27(31,35) sts now on needle.
Row 4: Purl.
Row 5: Knit.
Row 6: Purl.
Rep from * 4(6,8) times more, ending with right side facing for next row. 19 sts now on needle.
**Next row: K1, sl1, k1, psso, [yo, k2tog] to last 2 sts, k2tog. 17 sts now on needle.
Next row: Purl.
Rep from ** 6 times more, ending with right side facing for next row. 5 sts now on needle.
Next row: Purl.
Next row: K1, sl1, k2tog, psso, k1. 3 sts now on needle.
Next: P3tog (top point of cup), sl rem st onto crochet hook and, with right side facing, ch 3, work 20(24,28) hdc evenly down first side edge, ch 3 at corner, work 21(25,29) hdc evenly across bottom edge, ch 3 at corner, work 20(24,28) hdc evenly up second side edge, then sl st to 2nd ch of first ch 3, fasten off.

BRA TOP
With right side facing, sl st to ch 3 sp at bottom right-hand corner of first cup, then [ch 3, hcd] in same sp, hdc in each st along bottom edge to left-hand corner, ch 5, hdc in ch 3 sp at bottom right-hand corner of second cup, then hdc in each st along bottom edge of second cup to last st, 2 hdc in ch 3 sp at bottom left-hand corner of second cup, ch 3, turn.
Row 2: 2 hdc in first ch 3 sp, hdc in each st to last st, 2 hdc in last ch 3 sp, ch 3, turn.
Row 3: 2 hdc in first ch 3 sp, hdc in each st to last st, 2 hdc in last ch 3 sp, then work chain st to create strap 52 cm (20-1/2 ins) long, fasten off.
Sl st to first st on outside corner of rem cup, then work same-length strap in same manner.

BOTTOMS
Cast on 41 sts (front top edge).
*Row 1 (right side): K1, sl1, k1, psso, [yo, k2tog] to last 2 sts, k2tog. 39 sts now on needle.
Row 2: Purl.
Rep from * 4 times more. 31 sts now on needle.
Work St st, dec 1 st at each end of needle on every alt row 8 times, place marker. 15 sts now on needle.
Work even in St st until crotch from marker measures 12.5 cm (5 ins) or desired length, ending with right side facing for next row.
Work St st, inc 1 st at each end of needle on every row 23 times, place marker. 61 sts now on needle. (Note: If desired, widen and lengthen back by inc number of sts in rows, taking into consideration that crocheted edging will add 1 cm/3/8 in at each edge.)
Work even in St st until back from marker measures 19.5 cm (7-1/2 ins), cast off to last st, sl rem st onto crochet hook and, with right side facing, ch 3, work 62 hdc evenly along first side edge, ch 3 at corner, work 31 hdc evenly across top front edge, ch 3 at corner, work 62 hdc evenly along second side edge, ch 3 at corner, work 40 hdc evenly across top back edge, sl st to 2nd ch of first ch 3, then work chain st to create strap 39.5 cm (15-1/2 ins) long, fasten off.
One at a time, sl st to each rem corner on front and back, then work same-length strap in same manner.

To finish:
Using elastic, hand-sew line of running sts just inside each side edge of cups and bottoms. If desired, cut lining (having greatest stretch from front to back) piece about 6 mm (1/4 in) larger than crotch around edge, press under 1 cm (3/8 in) around edge; with matching thread, slipstitch in place to wrong side.