Anthrocera (thermophila) VICVE, 455 



Sexual dimorphism. — The similarity of the sexes of this species 

 is remarkable. On the whole, the females are larger than the males, 

 and rather less thinly scaled, whilst Boisduval observes that the 

 females occasionally have the ground colour greyish-green. The 

 largest female in our collection is 32 mm., the largest male 29 mm. 

 The former vary from 26 to 32 mm., the latter from 22 to 29 mm. 

 On the whole, the dark hind marginal border of the hind-wings is 

 broader in the males than in the females, especially in the eastern 

 races of the insect. 



Comparison of A. vici.<e with A. trifolii (-minor). — Some British 

 lepidopterists have suggested that our native A. viciae [(meliloti) is 

 not identical with the species known by the same name on the Conti- 

 nent. The specimens in the British Museum and our own collection 

 show that the insect we get exists unchanged in France, Germany, 

 Switzerland, Austria and Bussia. (The mixing up of the densely- 

 scaled, six-spotted, southern A. charon, Hb., with this species by some 

 continental authorities does not affect the question.) Nolcken notices 

 (Lep. Fn. Estland, p. 99) a pair taken in cop., among the typical form, 

 as having a " broad margin" to the hind-wings. Briggs reports (Proc. 

 Ent. Soc. Lond., 1875, pp. xiv-xv), breeding A. trifolii (-minor) from eggs 

 laid by A. viciae, but here some error of observation appears to have oc- 

 curred, Fletcher having since confirmed the fact that they not only 

 breed true and are quite distinct in all their stages, but that the larva 

 of our species agrees with Esper's description of the larva of his A. 

 meliloti. Bateson and Pierce find the male genital organs quite 

 distinct. A comparison of the imagines shows that A. viciae is 

 a more slender and less densely clothed species, with narrower 

 wings, semidiaphanous, even when fine, the green ground colour 

 duller, the red more carmine, never showing the solid scaling and 

 brighter coloration, the marginal border of the hind-wings very much 

 narrower, and the antennae more slender than in A. trifolii. Tugwell 

 says that the antennae of male A. viciae (meliloti) are one-fifth shorter 

 than those of the smallest A. trifolii he had, the thickening of the 

 club less sharp, and the end or tip more blunt. 



Variation. — There is little marked variation in the British and 

 Central European examples of this species. Some difference in size is 

 observable, and the width of the marginal border of the hind- wings varies 

 in both sexes. Considerable difference, too, occurs in the size of the lower 

 of the central pair of spots. Fletcher has bred an example (from the 

 New Forest) with traces of a sixth spot ; Bright has one, and Christy 

 four, examples from the same locality, with traces of this spot below the 

 apical one, and three others with a very slight redness of that part of 

 the wing where this occurs. Two similar specimens are in the British 

 Museum collection, in which the sixth spot is distinctly developed ; 

 these came from Stettin (Hering coll.). Esper's pi. xxxix., fig. 1, shows 

 a sixth spot on the underside, and Briggs states (Young Nat., ix., 

 p. 189) that this peculiarity is sometimes noticeable in British speci- 

 mens ; Bright notices it in two examples, whilst Christy notes a 

 suffused redness on the underside in the position which a sixth spot 

 (if present) would occupy. This form showing the sixth spot we 

 would call ab. sex punctata, n. ab. Aberrations also occur in which 

 the spots are more or less confluent. This confluence usually takes 

 place between 3 and 5. Such forms have occurred occasionally near 



