INSECT COALESCENCE. 221 



remains of the mesothorax of the ^ra^^/Zrt by a sheet of regener- 

 ated tissue which is exactly similar to the hairless bands con- 

 necting normal abdominal segments. On the ventral side a more 

 complicated condition appears. There is, of course, the sheet of 

 regenerated tissue which unites the fourth abdominal segment of 

 the promcthea to the thorax of the cccropia. To this sheet 

 of tissue are attached the bases of the coxae of the first pair of 

 legs, and the femoro-tibial joint of the right one as well. The 

 second and third pairs of legs and the wings arise normally in 

 their proper places. The antennae and palps are absent in this 

 specimen owing to the application of paraffine over the sacs, 

 thus blocking them off. 



It is obvious that this condition has been brought about as 

 follows : the growing edges of the opened leg-sacs, in regen- 

 eration naturally grew fast to whatever tissue extended over 

 them. This tissue was the regenerated band connecting the 

 bodies of the two components. Development proceeded nor- 

 mally, each part completing itself as usual, and presenting in 

 the freed complex the above condition. The reason why the 

 knee of one limb is also fused is evident when, we consider the 

 doubled-up nature of the leg -sac. The knee had been involved 

 in the slightly oblique section. 



The color-conditions are by far the most interesting. The 

 cecropia, as far as can be determined, possesses the normal 

 specific colors. Portions of tht p7^oincthea wrings, however, pre- 

 sent the colors characteristic of only the wings of cecropia. 



The promethea, it will be remembered, was a female. In ad- 

 dition to the pupal diagnostic character — the relatively smaller 

 size of the antennae — the imago was cut open, and eggs were 

 taken from the body, so that no doubt remains as to the sex. 

 There are but few traces in the imaginal wings of the charac- 

 teristic red-brown of this sex. In detail the colors are as fol- 

 lows : the upper surfaces of the anterior wings are mixed, buff 

 and slate. Upon magnification, the scales are seen to contain 

 only these* pigments. There are few containing the character- 

 istic reds and browns of a typical prometJiea wing. There is 

 about the center of the wing a patch of bright red scales similar 



