ACtRTADES THETIS. 369 



the 3rd abdominal right round the portion of the larva behind this, 

 and continuous round the thin posterior margin of the 10th abdomina 

 segment ; in front, the line is not continuous through the incisions, 

 and on the prothorax is represented by two spots — one below and one 

 above and in front of the spiracle, as if this were two segments. Below 

 this, half-way between the lateral flange and prolegs, is a series of yellow 

 spots, apparently on all the segments, but only clearly present on the 

 2nd and 3rd thoracic, and on the 3rd, 4th, 5th, and 6th abdominal 

 segments. The bases of prolegs have a faint yellow mark. All these 

 yellow marks are some way below the skin and separated from it by 

 green fluid or tissue, recognisable easily by noting the change of 

 position of the yellow marks when looked at from a different angle. 

 The general ground colour is a light apple-green, closely studded with 

 black points, the bases of the hairs. The hairs themselves appear to 

 be pale brown (ochreous, terra-cotta). The spiracles are conspicuous 

 black dots and the black spots at the angles of the prothoracic plate 

 are very obvious. The head is shining black. The true legs ochreous, 

 and rather transparent (Chapman). Final instar : About 16mm. 

 long, 6-25mm. wide ; the head small and retractile beneath the pro- 

 thorax, the segmental incisions deeply cut ; a double dorsal row of 

 eight humps from mesothorax to 6th abdominal, enclosing a slightly 

 hollow space, broadest on mesothorax, and thence tapering gradually to 

 6th abdominal ; the side spreads out to a rounded ridge running round 

 the body, and hiding the legs from view when the larva is at rest. In 

 colour, the head is very dark brown ; the body is deep full green, 

 covered with tiny black specks bearing little black bristles, which are 

 longest on the dorsal humps and subspiracular ridge ; on the top of 

 each of the eight pairs of dorsal humps is a deep bright yellow longi- 

 tudinal dash, somewhat wider behind than in front; these dashes form 

 in effect two yellow stripes interrupted by the deeply-cut segmental 

 incisions ; along the rounded edge of the subspiracular ridge is a stripe 

 of bright and very deep yellow going all round, save a slight 

 interruption on the sides of the prothorax, on which are two yellow 

 dots just above the head, and above them again two small black spots; 

 on the mesothorax there is a very faint yellowish dot half-way between 

 the dorsal and subspiracular stripes ; just above the prolegs is a row 

 of yellow longitudinal dashes, brightest on the feet-bearing segments 

 (in one example these dashes were curved upwards, and united at the 

 end of each segment to the yellow ridge above). In some specimens 

 the ventral prolegs are also marked with yellow ; the spiracles are 

 conspicuous, being round and black ; the pulsating dorsal vessel is 

 rather deeper green than the ground-colour (Buckler). 



Comparison of the larv#: of Agriades coridon and A. thetis (bel- 

 largus. — The general resemblance between the larvasof these two species 

 is so great as to render their separation and identification difficult, but 

 there are characters peculiar to each, which, with a little practice, 

 enable one to determine the question with little risk of mistake, at all 

 events in the later stages. The chief points of distinction appear to 

 be as follows : — 



1. The ground colour of the larva of A. coridon is of a bright clear green, while 

 that of A. bellargns is dull, opaque, and almost olive. 



2. The yellow wedge-shaped marks on dorsal prominences and sides of the 

 body, axe .clear bright primrose-yellow in A, coridon, clearly defined from the 



