Neptis hylas

Common Sailer
Upperside
Underside
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Family:	Nymphalidae
Genus:	Neptis
Species:	N. hylas
Binomial name
Neptis hylas (Linnaeus, 1758)
Synonyms
Neptis varmona, Moore, 1872 Neptis eurynome (Westwood, 1842)

The Common Sailer (Neptis hylas) is a species of nymphalid butterfly found in the Indian Subcontinent and Southeast Asia. It has a characteristic stiff gliding flight achieved by short and shallow wingbeats just above the horizontal.

See also: Neptis laeta

Description

Dry-season form - Upperside black, with pure white markings. Forewing discoidal streak clavate, apically truncate, subapically either notched or sometimes indistinctly divided; triangular spot beyond broad, well-defined, acute at apex, but not elongate; discal series of spots separate, not connate, each about twice as long as broad; postdiscal transverse series of small spots incomplete, but some are always present. Hindwing: subbasal band of even or nearly oven width; discal and subterminal pale lines obscure; postdiscal series of spots well separated, quadrate or subquadrate, very seldom narrow. Underside from pale golden ochraceous to dark ochraceous almost chocolate; white markings as on the upperside, but broader and defined in black. Forewing: interspaces 1 a and 1 from base to near the apex shaded with black, some narrow transverse white markings on either side of the transverse postdiscal series of small spots. Hindwing a streak of white on costal margin at base, a more slender white streak below it; the discal and subterminal pale lines of the upperside replaced by narrow white lines with still narrower margins of black. Antennae, head, thorax and abdomen black; the palpi, thorax and abdomen beneath dusky white.

Wet-season form - Differs only in the narrowness of the white markings and in the slightly darker ground colour and broader black margins to the spots and bands on the underside.

• 
  Upperside on right. Underside left
• 
  Mating pair, Bangalore, India
• 
  In Dumbara, Rathnapura, Sri Lanka
• 
  N. h. matuta
  Bali, Indonesia
• 
  N. h. matuta underside
  Bali, Indonesia

This species has been observed to make sounds whose function has not been established.

Distribution

Throughout continental India; Sri Lanka; Assam; Myanmar (Tenasserim), extending to China and Indomalaya.

Life history

Larva

Race var mona = eurynome. Frederic Moore describes this from a drawing by Mr. S. N. Ward (Samuel Neville Ward) as follows:

"Head larger than the anterior segment, vertex with two short pointed spines, cheeks obtusely spined; third, fourth, sixth and twelfth segments armed with a subdorsal pair of stout fleshy spiny processes, those on the fourth segment longest. Colour pale green; face, the tip of processes and segments slightly washed with pale pinkish, a slight pinkish oblique lateral fascia from an anal process; a small, dark, lateral spot on the sixth segment."

Pupa

"Rather short; head-piece bluntly cleft in front, vertex pointed; thorax dorsally prominent and angular; dorsum angular at base; abdominal segments slightly angled dorsally; wing-cases somewhat dilated laterally. Colour pale brownish-ochreous, with lateral thoracic golden spots."