no. i. BOMBYCINE MOTHS OF NORTH AMERICA— PACKARD. 9 



bears a black spinulated seta. Just below the spiracle is a small, simple, infraspiracular tubercle, 

 and below this a low minute 3-headed one. Behind this series of four tubercles (on each side) 

 is a dusky, narrow, chitinous band or rudimentary prothoracic plate or shield, which passes 

 down each side of the segment, not quite reaching a point opposite the spiracle, i. e., not as far 

 down as the spiracle. 



On the second thoracic segment are two dorsal tubercles (i), which are small, digitiform, 

 2-headed, the heads diverging. These are smaller than the corresponding pair on the first 

 abdominal segment, but larger than those of the hinder pair (ii) on the same abdominal segment. 



On the third thoracic segment is a pair of enormous horns, which are slightly more than 

 half as long as the body. They are not stiff, and easily bend over, but with a thin integument, 

 the surface of which is crowded with short, erect spinules, some of which are conical, others 

 blunt. These two appendages are nearly as thick as the segment is long, their greatest diame- 

 ter being a little above the base; they are forked at the end, each fork being about twice as 

 long as thick, and much rounded at the end, and giving rise to a stout spinulated seta, which is 

 of moderate length, i. e., about twice as long as the greatest diameter of the horn itself. The 

 horns of this pair are much larger than those of Aglia tau of the same stage, and differ in the 

 trunk, and two branches of the fork being much thicker, while the short spinules do not give 

 rise to a hair. It is most probable that the caterpillar moves these horns with more or less 

 freedom, and that they are deterrent structures. 



On the back of abdominal segments 1-7 are two pairs of dorsal tubercles, those of the 

 anterior pair (i) digitiform, as long as the horns are thick; they are separated by a space nearly 

 as long as one of the tubercles themselves. Those of the second pair (ii) are a little wider apart, 

 but situated close to the anterior pair, and with shorter and smaller seta?. The presence of a 

 second pair of tubercles on the tergum, the four tubercles arranged in a short trapezoid, is a 

 very primitive feature. I have observed them hi the first stage of Cerura, Heterocampa, Macru- 

 rocarnpa, and other Notodontidae, as well as in Anisota and Adelocephala, but not hi Eacles. 



The caudal horn is about as thick as the metathoracic horns, the distal half fully as thick 

 through, and the two divisions of the fork are of the same size, including the terminal setae. 

 It is also equally flexible, and its armature is the same, the surface behig beset with micro- 

 scopic conical spinules which do not end hi a hah. The horn is about half as long as the anterior 

 horns, extending a little beyond the end of the dorsal setae. 



The horn is the fused homologues of the anterior pair of tubercles of the abdominal seg- 

 ments in front, for directly behind its base is a pair of short tubercles of the same size and 

 shape as those of the posterior pah. 



The ninth abdominal segment is armed dorsally with a pair of separate tubercles like, in 

 shape and size, the anterior ones on segments 1-7, but situated close together at their base. 

 The suranal plate is triangular, about as long as broad, with three small marginal tubercles on 

 each side, and one twice as large near the base of the plate. The surface is not tuberculated. 

 The anal legs are flat, square, not rough and tuberculated, but bearing three small setiferous 

 tubercles near the lower edge. 



The tubercles of the subdorsal second row (ii) are simple and digitiform, as are those of 

 the third or supraspiracular row (Hi). These tubercles arise from a broad base, forming a dark 

 or reddish discoloration. The tubercles of the lower or fourth supraspiracular row (v, vi) are on 

 the abdomhial segments united at their base, those of the second and third thoracic segments 

 minute and single, as usual in all Ceratocampidae. 



The setae are peculiar in the microscopic spinules being stout, corneal, often blunt. They 

 are of nearly equal length, the longest one being nearly or about two-thirds as long as the seg- 

 ment is thick, and necessarily add very much to the defensive nature of the armature of the 

 young larva. 



The ground color, as shown by Mr. Joutel's drawing, is a reddish ochreous, the bases of the 

 tubercles being surrounded by light reddish brown; the tubercles are all red, the middle of the 

 big two dorsal horns and of the caudal horn being yellowish. There are no longitudinal or 

 transverse stripes. 



