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Psyche 
[June-September 
MORPHOLOGICAL DIFFERENCES BETWEEN FIRST AND SECOND INSTARS: 
In the second instar 6 7 , scoli and additional setae appear on the head 
(Figure 7); the chalazae of the first instar are replaced by scoli and 
verrucae; the setae are no longer serrate; the central pair of setae on 
the cervical shield is pale; a prothoracic subspiracular scolus 
appears (no prothoracic subspiracular chalaza in the first instar); 
mediodorsal armature appears on abdominal segments 1-8; the fol¬ 
lowing armature is lost: subdorsal chalaza on segment 9, the small 
chalaza between and posterior to the subdorsal and supraspiracular 
chalazae on segments 1-8, the subspiracular chalaza on segment 9, 
and the subventral chalaza on segments 8 and 9; a supraspiracular 
scolus appears on segment 10; the subventral chalaza on segments 
3-6 is now a pair of scoli; the suranal plate becomes triangular; the 
crochets become triordinal and are arranged in a mesoseries. 
third and subsequent instars: The head scoli are clubbed (slightly 
more so in A. amathea and A. fatima than in A. jatrophae ) in the 
third through final instars (Figure 7). The head width increases by 
factors of 1.5 (A. fatima), and 1.6 {A. amathea and A. jatrophae) 
(see Figure 8). The adfrontal sutures become conspicuous in the 
final instar, by which time the body is black, the scoli are reddish 
brown, and there are often coarse longitudinal stripes composed of 
light dots. The prothoracic eversible gland is present in all instars. 
The interspecific differences in larval morphology are very subtle. 
A detailed, comparative larval study must await the discovery of the 
larva of A. lytrea, and the collection of new material of A. 
chrysopelea. 
The number of instars is variable: A. amathea from Colombia 
had five instars (Muller, 1886; R. E. S. and A. A.); A. fatima from 
Panama had six (A. A. and R. E. S.); from Costa Rica five (Young 
and Stein, 1976); A. jatrophae 1 from Panama had five (A. A. and R. 
6 Dethier’s (1941) description, of a second instar A. jatrophae from Cuba, differs from 
ours in the number of scoli on abdominal segments 8-10, and in the reported absence 
of a subspiracular scolus on the prothorax. From his account of the first four instars 
of A. chrysopelea, the larvae of that species are very similar in setal arrangement to 
the three described above. However, he reports that the setae of the first instar larva 
“. . . do not arise from conspicuous sclerotized areas . . . .” 
7 Rawson (1976) reported three instars for A. jatrophae from Florida, but from his 
illustrations it is probable that he missed one or more instars; his “third” instar is 
probably a fifth or sixth. The sum of Rawson’s development times is also unusually 
short. Further rearing in Florida should be done to corroborate his account. 
