352 SOUTH- AFEICAN BUTTEEFLIES. 



times almost obsolete (as in Piirameis, fig. 4), so that the discoidal cell appears to he 

 open. In the Idnd-iving there are never more than two of these nervules, as only 

 one discoidal nervule exists ; and of them the second (lower) one is often obsolete or 

 absent entirely (as in Pyrameis, fig. 4 ; Libythea, fig. 5 ; and Rlwpalocampta, fig. 9). 



h. Interno-median nervule. In f or e-ioin g on\j. This minute transverse nervule is shown 

 in fig. 8, uniting the median and submedian nervures near their origin. It is only 

 found in the Papilionince and Morxihihn. 



k. Precostal 7iervure. In hind-iving only. This short curved nervure, close to the base, is 

 almost always simple, but in Papilio (fig. 8) and several allied genera, and in the 

 Sub-family Brassolince, is forked, its lower branch being then united to the costal 

 nervure so as to form a small prediscoidal cell.i The precostal nervure is wanting 

 in Liicana (see fig. 6), and apparently throughout the Family Lyccenidce, as well as 

 in several genera of Pierince. 



In fig. 4 {Pyrameis) is shown, along the hind-margin of both fore and hind wings, the fringe 

 (cilia) of hairs or hair-like scales more or less developed throughout the Lepidoptera. 



3. In the figures of the Head, figs. lA and 5A are viewed from below, fig. 9A from above, and 

 the remainder from the side. The following letters are used throughout to denote the several 

 organs, viz. : — 



aa. Antenvee. These m.any-jointed organs vary much in length and thickness, and the 

 thickening or club at tlieir tip is also very variable in the different groups as regards 

 size, shape, and gradual or abrupt formation from the main antenna. In the 

 HesperidcB (see fig. 9A) the antennas are widely separated at their origin, springing 

 from each side of the wide head, and the point of the club is prolonged into a 

 slender acute bristle, either bent at an angle or hooked. 



pp. Labial palpi. These organs, springing from the labium or under lip, are three-jointed, 

 but the extent and form of the third (terminal) joint only is readily perceptible, 

 owing to the second (middle, and usually much the largest) and first (basal) joints 

 being coated with scales and hairs. The extraordinary length of the palpi in 

 Libythea (see fig. 5 a) is due, however, to the unwonted development of the third 

 joint ; while in Papilio (see fig. 8a) these organs are so short as to rise only half as 

 high as the head, not projecting forward at all. 



ee. Compound Eyes. These great organs occuijy a large space on each side of the head. 

 They are always px-omiuent and globose, and present but little variation in size or 

 form. 



t. Trunk or haustellum. This consists of the greatly modified maxillos (second pair of jaws 

 in biting insects), forming together a tube for sucking liquid food. When not in use 

 it is spirally rolled up between the labial palpi. It is much longer in the Hesperidee 

 than in other butterflies. 



4. In the figures of the Legs (ib, 8b, and 9B) the various parts are distinguished by the 

 following letters, viz. : — 



a. Leg of first (front) pair. 



b. Leg of second (middle) pair. 



c. Leg of third (hind) pair, 

 f. Femur or thigh. 



t. Tibia or shin. 

 ts. Tarsus or foot. 



In fig. IB all three legs of Danais are shown (a. b, c). The front leg is not a quarter the size 

 of the middle or hind leg, and its tai-sus is reduced to a single joint, with the minutest rudi- 

 ments of two other joints (see fig. a', magnified), instead of having the five joints and pair of 

 terminal claws possessed by the other (normal) legs. The spurs at the end of the tibia are 

 unusually small in both middle and hind legs. 



In fig. 8b the front and hind legs of Papilio are given (a, c). The front leg (a) is quite as 

 fully developed as the others, the tarsus possessing the five usual joints and the terminal claws. 

 The spurs at the end of the tibia are well developed in the middle and hind legs, and the tibia 

 bears on its inner (inferior) edge a large acutely-pointed process. 



In fig. 9B (Rhopalocampta) the front and hind legs are shown (a, c). As in the Papilionidce, 

 the front leg is fully developed, and also hears a process (similar to that in Papilio) on the tibia. 

 On the tibia of the hind-leg (c) there is a second pair of strong spurs at a little distance above 

 the ordinary terminal ones. The femur of all the legs and the tibia of both middle and hind 

 legs are densely clothed with hair. 



Note. — The student will find it serviceable to consult this Plate, and the explanatory details 

 Iiere given, in connection with the remarks on the sti-ucture and classification of butterflies 

 above offered (pp. 15-22) under the heading of *' Rhopalocera ; " and also with the particulars 

 as to distinguishing characters given under each Family, Sub-family, and Genus in the body of 

 the work. 



1 The smaller and less complete pi-ediscoidal cell found in several Hcsperido'. (see Rhoi'ialocampta, 

 f. 9) is differently formed, between the costal and subcostal nervures, at the very base of the discoidal 

 cell itself, by the downward flexure and sub-angulation of the subcostal nervure. 



