72 BRITISH BUTTERFLIES. 



ventral and equidistant between the claspers and dilated margin 

 (Newman). 



Comparison of larv.e of Agriades thetis and A. coridon. — In the 

 first stage, I find no difference that is appreciable between the larvae of 

 the two species except in the minute hairs between the subdorsal lenticles 

 and the spiracles. In A. thetis these are very minute, and I think often 

 replaced by minute lenticles, and occasionally one or other is absent, as 

 in the example figured (antea, vol. x., pi. xliv., p. 363), in which only one 

 is present on the 2nd and 3rd abdominal segments. In A. coridon the 

 hairs are practically always visible, are curved and club-shaped, and 

 twice as long as in A . thetis, when they are present in that species. Taken 

 altogether, the lenticles and hair-bases appear to be larger and bolder 

 in coridon than in thetis, and even the prothoracic plate larger. 

 Against this I must, however, note that much of my observation of 

 A. coridon was on examples from Riviera eggs which are larger than the 

 British ones (racially or seasonally ?), and so the larvae may have 

 been correspondingly larger and more robust. In the following instars 

 I am unable to say anything decidedly as to any structural differences 

 between the two larvae. In the last instar the small hairs on the 

 slopes seem rather longer and less curved than in A. coridon, the width of 

 the prothoracic plate is also greater in coridon, viz., about 1-OOmm. 

 against 0'85ram. in thetis, and the hairs are decidedly shorter and 

 smaller in A. thetis (Chapman). The larvae of these two species resemble 

 each other in every detail of form and ornamentation, except the 

 following two points : The larya of A. thetis has (1) the ground colour 

 deeper green, with (2) the hairs or bristles black, whilst that of A. 

 coridon has (1) the ground colour of a lighter brighter green (a green 

 with more yellow in its composition), and (2) the hairs light brown 

 (Hellins). Zeller states (Stett. Ent. Ztg., 1852, p. 425) that " Bois- 

 duval's larva of adonis (Icon. Chen., pi. ii., figs. 4-5) has the spiracles 

 black, very conspicuous, with broad border, forming a series of spots 

 in line, whilst his larva of coridon (op. cit., figs. 1-2) has them ' black, 

 very small, scarcely visible to the naked eye,' whereas Zeller's own 

 larvae of coridon appeared to be exactly like those of Boisduval's adonis."' 

 [See also antea, vol. x., p. 369.] 



Pupation. — The fullfed larva appears to travel some distance in 

 order to find a suitable place for pupation. On August 13th, 1909, 

 just above Franzenshohe, on the Stelvio, a full-fed larva was found 

 crawling in the dust on the roadway, and was put into a box, in which 

 it had changed to a pupa by August 26th, without further feeding. 

 Lowe mentions (Ent. Record, xvii., p. 80) the capture of other larva 1 , 

 also on the Stelvio, under almost exactly identical conditions ; he 

 observes that " the dust was thick in the road, and the larva- left deep 

 tracks, and were themselves coated with dust ; they were removed to 

 the larva-cage and duly pupated." On June 9th-10th, 1909, a fullfed 

 Larva (from Reigate) in confinement got very restless, and travelled 

 about a good deal and then disappeared ; on the morning of the 14th, 

 it was discovered in a hollow on the surface of the ground at the roots 

 of the foodplant, quite hidden from sight, and only detected when the 

 root was pulled aside, its bright green colour and yellow spots (which 

 appear to get paler when the larva, is quite fullfed) quickly leading to 

 its detection. It appealed to have spun a loose silken thread or two, 

 to hold a few stalks of the Hippocrepis and a few dried grass stalks 

 together, but if so, they were so weak that they broke as soon as the 



