226 BRITISH BUTTERFLIES. 



more casual, use of it by Herrich-Schaffer in the explanation of fig. c 

 in pi. vii. of the 146th number of his Forsetzung Panzers Insekten 

 Deutschlands, where it stands thus: " Kopf einer Aricia (agestis).'" 

 This, in our opinion, constitutes medon (agestis), the type of the genus, 

 but even by those who dissent from this ruling, our action in the Ent. 

 Record, xviii., p. 131 (1906), would be accepted as conclusive. 



The genus Aricia, Sav., is sometimes erroneously quoted in Vermes 

 for 1817. Its proper date is 1826, the year in which Savigny's Systeme 

 des Annelides was published, and, though the work was in MS. in 

 1817, it is quite impossible that the name can have appeared in print 

 before February, the date of E. L.'s review. The question is fully 

 dealt with by Prout, Ent. Record, xxi., p. 156. The priority of Aricia 

 in Lepidoptera over the same genus in Diptera and Mollusca is of 

 still greater extent, the former having been published in 1830 by 

 Desvignes, and the latter in 1832 by Gray. 



The genus Aricia, as thus restricted, with medon as its type, was 

 defined in Brit. Butts., iii., p. 156, as " the group whose larvae feed on 

 Geraniaceae," and it was there noted as being, next to Flebeius, the 

 most distinctly separable section of the group by means of the 

 ancillary appendages. In the present volume also, p. Ill, we gave at 

 length Chapman's account of the comparative differential characters, 

 which it is needless to repeat. He also dealt at length (Ent. Rec, 

 xxii., p. 101) with the differences in structure of the Plebeiid (sensu 

 lato) aedceagus, his remarks with regard to the present genus being as 

 follows : — 



" Aricia has a highly characteristic structure, very different from the two we 

 have been considering [Agriades and Polyommatus] . In this, the portion beyond 

 the zone is much prolonged. It may be noted that, throughout the Plebeiids, the 

 portion of the aedoeagus within the zone does not vary much in length in the 

 different species, generally about 0*65mm. in length, it varies in different species 

 from 0*55mm. to 0'8mm., rarely outside these limits. The portion beyond the 

 zone varies much more widely — in Agriades about 0*22mm., in Aricia it is nearly 

 0'8mm., longer than the basal portion. It tapers gradually to a point, and 

 appears to have a long lateral opening instead of the nearly terminal one in the 



shorter examples Anteros and isaurica have a very similar 



sedceagus."* 



In vol. iii., p. 156, we placed idas, donzelii, and eumedon with 

 medon (astrarche) in this genus, and in the article quoted above, 

 Chapman observes that these are the only species that unquestionably 

 belong here, but adds that isaurica, ht/acinthus, fulla, and anteros may 

 do so. Graves has since shown Erodium to be the foodplant of the 

 larva of the first-named, which seems conclusive for that species in 

 connection with the form of the genitalia, and we provisionally 

 include the other three species also.f 



The Ariciid egg differs somewhat from the usual Plebeiid type in 

 not being quite flat at the top. It is possible that this slightly domed 

 form indicates Theclid affinities, traces of which Chapman also finds 

 in the lengthened form of the sedcoagus, and which are further sug- 

 gested by the dark colouring of some of the species, idas and eumedon 

 as well as medon, which, however, passes through the dull grey-blue 



* See pi. x., fig. 4 (facing p. 111). 



t Chapman definitely states (in litt., June 3rd, 1912) that fulla is an Aricia 

 (G. W.). 



