AGRIADES THETIS. 337 



brown-black = ab. atrescens, n. ab. The antemarginal chevrons in the<? 

 are sometimes red, but occasionally they are merely grey (ab. initio), pale 

 ochreous being much more frequently the tint ; in both wings, those 

 nearest the anal angle are usually the more brightly coloured, and 

 those on the hindwings brighter than those on the forewings ; in the 

 $ , they are frequently of a quite bright orange-red colour. The base of 

 the hindwings varies from metallic-green to metallic-blue. The spots 

 on the undersides vary considerably in size ; some are exceptionally 

 large, as figured by Bergstrasser (Nom.,iii., pi. liii., fig. 6) ( = ab. crassi- 

 puncta, Courv.); in others they are exceptionally small, and tend to obso- 

 lescence, without, however, being actually absent ( = ab. parvipuncta, n. 

 ab.). The normal spotting (omitting the marginal series) on the under- 

 side of the forewings, consists of seven (occasionally eight) black, white- 

 margined, spots in the submedian series, the two nearest the inner 

 margin in the same interneural space, and often united, and two 

 similar spots between the discoidal lunule and the base ; the hindwings 

 have a submedian row of eight spots, and three or four basal spots ; 

 very rarely the spots are not black-centred, but only the white rings, 

 suffused inwardly, remain = ab. albo-ocellata ; still more rarely the black 

 spots have no white margin = ab. nigro-ocellata. The variation in the 

 number of spots may be in the direction of increase or decrease. Those 

 examples showing an increase in the number of spots are known as ab. 

 addenda ; those which show a decrease, as ab. obsoleta. The most 

 extreme forms of ab. addenda have, sometimes, several small spots 

 between the submedian and the discoidal, and the basal and discoidal, 

 whilst there is often a duplication of the basal spots in the forewing, 

 and an increase of those ot the hindwing. The most extreme forms 

 in the direction of obsolescence, have no spots except the discoidal = 

 ab. obsoleta, Tutt ( = ab. krodeli, Gillm.) ; one of the most common 

 forms of obsolete variation is the absence of one or both of the basal 

 spots on the forewings, and the basal spots of the hindwings may be 

 reduced to two or one, the latter rarely. The discoidal spot on the 

 underside of the forewings is sometimes doubled (discoidalis- duplex); 

 on the other hand, Grosvenor observes (Ent., xl., p. 300) a specimen 

 without the discoidal spots (discoidalis -nulla). Courvoisier names 

 (Mitt. Sch. Ent. Gesell., xi., p. 22) a number of these slight obsolete 

 variations, e.g., he observes that the normal number of spots at the 

 base of the forewings is two, and calls the examples with three basal 

 spots, ab. tripuncta, those with four, ab. quadripuncta, whilst (op. cit., 

 p. 24) those with one basal spot are called ab. unipuncta, and those 

 with none, ab. impuncta. The extension or union of the spots into 

 streaks is a not uncommon form of variation, and, in 1896, we described 

 these various forms under the collective name striata. These streaked 

 forms, however, are traceable along two entirely different lines of 

 development, (1) the streaks formed by the union of two or more 

 spots by a connecting bar = ab. conjuneta, (2) the streaks formed by the 

 extension of the ordinary spots = ab. striata, in its more restricted 

 sense. Some of the individual aberrations of the form striata, sens, 

 lat., have been separately named by Courvoisier and others, e.g., Cour- 

 voisier describes (Mitt. Sch. Ent. Gesell., xi., p. 20) a form, in which 

 the lower basal spot is united to the lowest spot of the submedian row, 

 as ab. arcuata; similarly, he calls the form in which the confluence 

 between these spots is not quite complete ab. semiarcuata. To 



