Dicranura vinula, and other Notes. 121 
(vide Figs. 7, 8, 9). Atthe posterior end of the duct, and 
in the gland proper, the cells are very large with fluted 
sides, and the secreted chitin is extremely thin and 
often difficult to identify, though I believe it to be always 
present, the plasma of the cells is relatively far more 
abundant, and presents a curiously striated appearance at 
its free border owing to vacuolation of this portion of the 
cell, at the same time the nuclei are of great size and 
branch out into numerous blunt processes corresponding 
with the external flutings. The general appearance both 
of the cell plasma and of the nucleus is very similar to 
that of the cells of the silk-glands. 
I now pass on to consider the homologies of this sternal 
prothoracic gland and of similar structures. 
Bernard (1) has endeavoured to show that the tracheze 
arose from setiparous sacs of a Chzetopod ancestor, and 
considers that the stink-glands of Julus among the Myria- 
poda represent the glands of parapodial sete, while coxal 
glands may represent acicular gland sacs. Packard (10) 
has expressly stated his opinion that these sternal glands 
of lepidopterous larve are the homologues of coxal 
glands of other Arthropods, and, if I understand him 
aright, that the same view is tenable of the lateral and 
dorsal glands of many species of larvee. In the following 
discussion I shall confine my attention to the sternal 
glands, and chiefly to those cf Lepidoptera. It is very 
striking to note how large a number of the segments of 
the entire body possess, in various species, structures 
which may with reason be regarded as serial homologues 
of the gland seen in D. vinula. <A tabular arrangement 
will show this most clearly. 
Head segment. 1, Oil (stink) glands opening at base of 
mandibles of C. ligniperda.* 
3. Silk glands.+ 
Thorax. 1. All species of Dicranuwra (Ceruwra), Ma- 
crurocampa marthesia, Packard (11), 
Schizura concinna (id.); species of 
Lacosoma, Astyanax, Danima, Nola, 
Hyperchiria, Hyponomeuta, and Plu- 
sia, Schaffer (19). 
* Salivary glands; glandules of Filippi. I prefer not to assign 
these to any definite segments. 
+ Biitschli, Zeit. wiss. Zool. Bd, 20, 1870. 
