88 BEITISH BUTTERFLIES. 



(Ent., xxxvi., pp. 228-230), and the differences they present are very 

 interesting. He describes them as : 



1. " Plumulae subulatse " or " Bristle plumules," in which the end is produced 

 into a single bristle. Found in the costal fold in Hesperia malvae. 



2. " Plumulae capillares "or " Hair bristles," slender, fine as a hair, obtuse 

 at end. Found in costal fold of Nisoniades tages [also on upperside of wings of 

 many Lycaenid species] . 



3. " Plumulae articulatae " or "Jointed plumules," slender, nearly smooth, 

 divided into many joints, easily separable from one another. These are the 

 remarkable scales which are so closely packed together in the s discal sacs of the 

 true Urbicolids (Pamphilids), e.g., Urbicola comma. 



The " tibial epiphysis," to which reference has already been made, 

 appears to be a very marked character in some genera, variable in 

 others, being present in some species and absent in closely allied ones, 

 whilst it is even said to be present in some, and wanting in other, 

 individuals of the same species, e.g., Abantis tettensis. It may here be 

 noted that, although the terminal and median spurs are usually present 

 on the hind tibiae, the pair on the middle tibiae is sometimes absent. 

 Watson considers this character to be usually of generic value, 

 although, in certain Cyclopidines, he holds the presence or absence to 

 be of specific value only. 



The antennae vary much, the apical portion being markedly different 

 in shape in different groups. The club may be " hooked " when its terminal 

 portion is bent to less than a right angle with the remainder of the 

 club, or " sickleshaped " when the whole of the club is evenly curved 

 and not abruptly angled, or " bent " when the club is abruptly angled 

 but not hooked. Jordan describes (vide Ent. Record, xi., p. 86) four 

 different kinds of special organs and structures as being present on 

 butterfly antennae, viz., "scales," "fine sense-hairs," " setiferous 

 punctures," and "sense-bristles." He also draws particular attention to 

 the special " form of antennal joints." His summary of the characters 

 presented by the Urbicolid (Hesperiid) (sens, lat.) antenna reads as 

 follows: — "A typically Hesperiid character is the ventral widening of 

 the joints of the club, giving it the well-known hook of that family. 

 The joints are cylindrical, without raised lines or grooves. The 

 scaling is very extended, covering the whole dorsum except, in rare 

 instances, the last joint ; the ventral surface is also scaled, except a 

 greater or less portion of the club. There are no setiferous punc- 

 tures, the bristles appear to be typically on the non-scaled area, a 

 transverse row of seven, usually apical, but may be reduced even to 

 two lateral ones." Chapman observes (lor. <it., p. 123) that "the 

 Urbicolids (Hesperiids), in preserving a very complete coating of 

 scales, are only illustrating their relationship to the earliest lepi- 

 doptera. There is much reason to believe, on antennal evidence, that 

 the Lycamids and Urbicolids originated in a common ancestor before 

 either group was clearly denned, in which the terminal antennal 

 joints probably possessed dorsally both hairs and scales. On the 

 Hesperiid antenna the hairs vanished, the scales persisted ; in the 

 Lycsenid antenna the scales disappeared and the hairs persisted. 

 Chapman thinks that the ancestral Lycaenid had scales on the dorsal 

 aspect of the terminal joints, and, in fact, all over the ventral surface 

 also, whilst there seems nothing to prevent the hypothesis being held 

 that the dorsal hairs have maintained their position right through, 

 from the scaleless antenna of the non-lepidopterous ancestor, and 



