Watt. — Ova of some of the Lepidoptera of New Zealand. 75 



area appears to one side of it. The hairs of the larva are first to be seen, 

 and later the larva itself is plainly distinguishable. Infertile eggs turn a 

 slightly darker shade of green, and in a week or so collapse. 



Note. — Laid in large flat bunches in irregular rows. Batches of 92 and 

 140 eggs obtained. Strongly attached to box and slightly to each other. 

 Laid, 15th September; hatched, 30th September = fifteen days. The larva 

 emerges through the top of the egg, and makes its first meal off the shell. 



(Described, 15th September, 1912.) 



Orthosia immunis Walk. 



Taeniocampa immunis Walk., Noct., 430. Cerastis innocua, ib., 

 1710. Agrotis acetina Feld., Reise Nov., pi. cix, fig. 6. Orthosia 

 immunis Meyr., Trans. N.Z. Inst., 19, p. 30 ; Fereday, List N.Z. 

 Lep., Trans. N.Z. Inst., 30, p. 335 ; Hudson, N.Z. Moths and 

 Butterflies, p. 7, pi. 5, fig. 29. 



Fairly common. To be taken in great numbers at " sugar " and on 

 street-lamps. 



Class. — Upright. 



Shape. — Transverse section circular (as a rule). Vertical section : Base 

 flat ; sides bulging outwards and curving in towards the top ; top. flattened 

 Diameter of top, 0-23 mm. 



Dimensions. — Diameter, 0-65-0-70 mm. ; height, 0-47-0-55 mm. 



Sculpture. — Strong. High reticulations or ribs radiate from the rnicro- 

 pylar cap to the equator, converging below. About one in two of the ribs 

 coalesce with another a little above the shoulder of the egg, and there is 

 irregularity in this respect ; in more than one instance three ribs coalesce. 

 Thirteen to seventeen ribs meet the micropylar cap. There are from 

 thirty-one to thirty-seven ribs in all. Between the ribs equidistant finer re- 

 ticulations form quadrilateral cells about twice to three times as broad as 

 long, measurements being — width, 0-05-0-06 mm. ; length, about 0-02 mm. 

 Height of longitudinal ribs, 0-01-0-03 mm. ; distance apart at equator, 

 0-05-0-06 mm. Base heavily wrinkled, but not sculptured. 



Micropyle. — A deep moat surrounds a correspondingly high eruption 

 which bears the micropyle, crater-like. The micropyle is a deep circular 

 cell 0-01 mm. diameter. The eruption is ribbed longitudinally with fine 

 reticulations forming a rosette of thirteen elongated cells surrounding the 

 micropyle ; from these the main ribs or reticulations of the egg originate. 

 The floor of the moat is composed of a band of eighteen hexagonal cells, 

 0-045 mm. long by 0-02 mm. wide, lengthened in a direction radial from the 

 micropyle. Depth of moat or height of eruption, 004 mm. ; diameter of 

 eruption, 0-07 mm. ; width of moat, about 0-05 mm. 



Shell. — Very strong ; transparent ; shiny ; roughened, and slightly 

 wrinkled between reticulations. 



Colour. — When fresh laid, white. The second day there is a slight 

 cream tint, changing later to light yellow. On the fourth day the upper 

 half of the egg is lightly mottled with very light brown. On the fifth day 

 there is a distinct broad light-brown band surrounding the egg just above 

 the equator, and a large irregular brown patch covers the micropylar area. 

 The brown coloration now greatly intensifies in shade, the micropylar area 

 being slightly lighter in colour than the equatorial belt. The day before 

 hatching all the light colouring on the shell between the brown areas turns 



