1894.] - NEW YORK ACADEMY OF SCIENCES. 55 
chitinous rod (see Fig. 4, A), absent in the case of tubercles ii, 
and but a single rod bears iv and vy. Dorsally on the 8th ab- 
dominal segment, the two tubercles i are usually consolidated* 
and sometimes also on 9th segment. Or the tubercles may be 
enlarged and bear a crown of hairs or become developed into a 
bunch of spines. In cludes the families Citheroniide, Hemi- 
leucidz, Saturniide and Bombycide. 
I cannot endorse the separation of the Hemileucide and 
Saturniidze on the characters used by Prof. Smith. Ac- 
cording to his arrangement, in the Saturniide the antennze 
are doubly bipectinate in the ¢, in the Hemileucidz singly. 
Now the several genera present a most interesting gradation in 
this respect, the females being generally behind the males in de- 
gree of specialization. Clearly it is an arbitrary division to 
draw the line between these families on characters exhibited by 
the male sex alone without further evidence that this separation 
really corresponds to a dichotomous division in the line of de- 
scent. If the female sex had been chosen instead, the division 
would have corresponded to those defined below in the synopsis. 
The families could be thus described : 
Family Hemileucide. Antennae of 2 moth singly bipectin- 
ated, of ¢ either singly or doubly so. Larve with primitive 
first, stage, a dorsal tubercle on 9th abdominal segment and 
none on the anal plate. Tubercle shafts densely covered with 
sharp defensive spines. 
Family Saturniide. Antenne of both sexes doubly bipectin- 
ated. Larve lacking the primitive first stage; no dorsal 
tubercle on 9th abdominal segment, but a pair on the anal plate. 
Tubercle shafts short or smooth with few weak spines or hairs. 
This is essentially the arrangement in Mr. A. R. Grote’s check 
list of 1882 and seems superior to any that has followed it. 
In the European Aglia tau, the larva possesses all the charac- 
ters of the Saturniidz, but differs in the great inequality in de- 
velopment of the tubercles. Their final disappearance in the 
last stage is less distinctive (compare the American Samia 
ceanothi). In theimago the male antennz are doubly bipectina- 
ted ; the female antenne are serrate (singly). This combination of 
characters probably entitles the genus to family rank. Dr. Pack- 
ard (N. Y. Ent. Soc. 1, 7, 1893) “places it as a subfamily of the 
Ceratocampidee (— Citheroniidee) ; but this is negatived by the 
arrangement of the larval tubercles (though favored by their 
unequal development) and by the structure of the antenne of 
the moth. 
* Except in Anisota. I find that | i and ii are both present, i une envenidated. I for 
merly erroneously supposed i to be absent (Ann. N. Y. Acad. Sci., viii., 232). 
