MALAC0S0MA CASTRENSIS. 531 



this a transverse submarginal shade ; cilia with two dark patches on 

 outer margin. Posterior wings unicolorous reddish- or coppery -brown, 

 a faint median transverse shade ; cilia pale. 



Sexual dimorphism. — The males differ entirely from the females in 

 their smaller size, averaging 28mm. -34 -4mm. against 8 5mm. -40mm., 

 their strongly pectinated antennae, the squarer- shaped wings, the 

 character of the transverse markings which usually form dark lines in 

 the males, and pale fascias in the females, as well as in the generally 

 paler ground coloration. The small robust build of the males denotes 

 a rapid flying habit, which appears quite impossible to the larger, 

 rounder-winged females with their heavy egg-filled abdomina. 



Gynandromorphism. — Several gynandromorphous examples appear 

 to have been described. The following are those we have discovered : 



a. A specimen with the left half having the appearance of a pale male, the 

 right half that of a dark female ; the division of colour on the thorax very apparent. 

 The upper part of abdomen of the same colour as is usual in female specimens, but 

 beneath it is longitudinally divided into dark and light, as also are the legs (Ingall, 

 Entom., xxviii., p. 42). 



/3. A specimen in which neither side is definitely male nor female, in general, 

 the male sex predominates ; head pale yellow ; left side a <? antenna and $ wings, 

 right side a ? antenna and c? wings. The collar yellow-haired, on the right side 

 mixed with brown; the thorax yellow-haired, on the left side and to a limited extent 

 in the centre, with the brownish hairs of the ? . The right hindwing in form and 

 colour $ . The right forewing male in colour, but very slightly larger, the base 

 and costa with brown scaling, similar to the brown colour of the ? body. The left 

 wings ? , but not quite fully developed. In the Berlin Museum coll. From Kirstein's 

 coll. Probably bred (Schultz, lllus. Wochenschrift fur Ent., L, p. 381). 



y. I have in my collection a hermaphrodite Bombyx castrensis, bred by me 

 in July, 1829. Having reared the caterpillar with a number of others of the two 

 sexes, ... I was surprised to find this individual presenting distinctly the two 

 sexes [Duval, Ann. Mag. Nat. Hist., iv., p. 150 (1831)]. A figure of the specimen 

 is given which shows the right antenna, and the right pair of wings distinctly male, 

 the left antenna and left pair of wings as distinctly female. The abdomen in the 

 drawing (fig. 26) looks entirely female, although the thorax is clearly bisected by 

 a line separating two quite differently coloured halves. 



5. A gynandromorphous example of M. castrensis var. veneta. The left side 

 <S , right side ? , in marking, colour, and size of wings, as well as in the antennae. 

 Body male in form. Bight wings 18mm., left wings 15mm. Bred by Standfuss at 

 Monte Botondo, near Borne, in 1882, now in Wiskott's coll. (Schultz, lllus. Wochen- 

 schrift fur Ent., L, p. 382, ii., p. 413). 



e. Left side ? , right c? . On the upper and under side the characters of the 

 two sexes sharply separated. The left female wing considerably larger than the 

 right male wing, being 15mm. and 11mm. respectively. The colour-distinction on 

 the thorax and abdomen, both on upper and under side, very distinctly contrasted, 

 divided exactly in the middle from the forehead to the end of abdomen. Legs on 

 the right side bright ochreous-yellow, on the left side brown. Antenna on right 

 side £ , bright ochreous-yellow, on the left side ? , reddish-brown. The genital 

 organs, also distinctly equally halved, with very prominent light-coloured anal tuft 

 on the right side. Bred in Berlin. In coll. Wiskott, Breslau (Wiskott, Festschrift 

 Verein Scliles. Insectenkunde, p. 28, pi. iii., fig. 12). 



£ . Incomplete. According to the form of the wings, <? . The colouring <f and 

 ? mixed. The abdomen in form and size ? , with rough and bristling anal tuft 

 on right hand side, the hairs on the left side lying smooth and flat, the two sides 

 differently coloured. The same colour difference also on the underside. Legs on 

 the left side brown, on the right side bright ochreous-yellow. Antennae right J , 

 left ? , in colour and form. Bred in Pesth. In coll. Wiskott, Breslau (Wiskott, 

 Festschrift Verein Schles. Insectenkunde, p. 28). 



■q-i. Three further gynandromorphous specimens of this species are noted as 

 being in the collection of Staudinger. No description is given (Schultz, lllus. 

 Wochenschrift fiir Ent., ii., p. 399). 



The following specimens have also been recorded as gynan- 

 dromorphous : 



hh2 



