1890.] 
107 
[Packard. 
The paranal forks . — We have already called attention to these 
two bristles in our description of the larvae of Cerura. (See these 
Proceedings, xxiv, p. 553). They are well developed, arising from 
the end of a papilla projecting directly backwards. Their use has 
been indicated by Mr. John Hellins 1 who refers to a pair of sharp 
points underneath the anal flap, “which are used to throw the pellets 
of frass to a distance.” Occurring in Notodontian and other arboreal 
caterpillars, notably the tree-inhabiting Geometrids, they are want- 
ing in Noctuidse (including Acronycta and Catocala) , Sphingidae and 
Rhopalocera, as well as the lower Geometrids and the Microlepi- 
doptera, and are not developed in the Sphingidae. In Ichthyura 
(Clostera) they are slightly developed. In the European Ur apte- 
ryx sambucata (received from M. P. Chretien) these lobes are very 
large, papilliform and setiferous ; and in our Choerodes, etc., they 
are similarly developed ; and the use of the two setae or the fork, 
is undoubtedly the same as in Cerura. 
The infradnal lobe . — My attention was first called to this lobe, 
or flap, while examining some Geometrid larvae. It is a thick, coni- 
cal, fleshy lobe or flap, ending often in a hard chitinous point, and 
situated directly beneath the vent. In appearance it is somewhat 
like the egg-guide of the Acrydii, though the latter is thin and flat. 
Its use is evidently to aicf in tossing the pellets of excrement away 
so as not to allow them to come in contact with the body. In a 
large not identified Geometrid worm, which lives on the ash, this flap 
is large, conical, ending in a blunt chitinous point. In a large ge- 
ometer belonging to another genus, the tip is sharper and harder ; 
and in what is probably a larva of Endropia, while the paranal forks 
are well developed the infraanal lobe ends in a stiff bristle. Whether 
this infraanal lobe is the homologue of the ninth urosternite or ven- 
tral plate I will not at present undertake to say. 
VIII. THE DISTRIBUTION OF GLANDULAR SETiE IN THE EARLY STAGES 
OF LEPIDOPTEROUS LARVAE. 
While, so far as we know, Zeller was the first to call attention 
to the glandular hairs or setae of caterpillars, and Dimmock 2 has 
particularly described those of the Pterophoridae, stating that they 
exude gummy matter secreted by a gland situated on the conical 
wart from which they arise, they do not appear to have been gen- 
iBuckler’s Larvae of the British Butterflies and Moths, Ray Society, ii, 1887, 142. 
“On some glands which open externally on insects. Psyche, ill, 387-401. 1882. 
