88 Annals Entomological Society of America [Vol. XIV, 
certain larvee two lobes appear, and, as far as I know, only one carries 
muscles.”’ (The lacinia, ‘‘la,”’ of Fig. 11 is thought by Dr. Craighead 
to carry no muscles, thus resembling the inner lobe of the maxilla of the 
larval Coleoptera, in this respect). He also states that ‘in certain 
forms there are indications pointing toward a maxilla with only lacinia 
or only galea present.’’ In this connection, it may be remarked that 
the tentorio-labiostipital and tentcrio-palpigeral muscles labeled ‘‘9”’ 
and ‘‘10”’ in Figs 11 and 14, as well as the submento-mental muscles 
labeled ‘‘11’’ in these figures are the same in adult and larva of Corydalis, 
so that all of the important parts of the trophi (with the exception of 
the maxillary lacinia) of an adult Corydalis are represented in its larva. 
Although there is a slight difference between the mouthparts of an 
adult and larval Corydalis, as was mentioned above, the mouthparts are 
essentially the same in both larva and adult of the lower Neuroptera 
(Corydalis, Sialis, Raphidia, etc.), the resemblance between the mouth- 
parts of the two stages being very marked in Raphidia (a larva of which 
is shown in Fig. 12), thus indicating a much feebler tendency toward 
complete metamosphosis in lower Neuroptera. When we turn to the 
larvee of the higher Neuroptera, however, we find a much stronger 
tendency toward complete metamorphosis, and the mouthparts for the 
most part have become so greatly modified in adaptation to the “‘larval’’ 
methods of getting food, etc., (most of these larvee suck the blood of their 
prey) that it is very difficult to determine the interpretation of the 
terminal pertions of the maxille, and until suitable material for dis- 
secting the muscles has been obtained, the interpretation of the homol- 
ogies of the terminal portions of the maxille is largely a matter of guess- 
work. Dr. Tillyard has suggested to me that the slender terminal 
portion of the maxilla bearing the label “‘mx”’ in the neuropterous 
larvee shown in Figs. 46, 44, 51, etc., may represent the lacinia labeled 
“la”? in Fig. 23 of the larva of Sialis, and there is much to be said in 
favor of this view. On the other hand, the structure in question may 
not represent the lacinia ‘“‘la”’ of Fig. 23, but may rather be homologous 
with the galea-bearing (or palp bearing) structure labeled ‘“‘ds”’ in Fig. 
23, with which the galea (or the palp) has fused, and the interpretation 
of the structures in question can be definitely determined only when 
material suitable for study has been obtained for an examination of 
the musculature—although the remarkable larvee of Jthone recently 
discovered by Dr. Tillyard may throw some light upon this subject. 
The mandible of an insect represents a single basal segment of a 
trilobite limb, as can be seen by tracing the development of the mandi- 
bular appendage through a series represented by the trilobite Triarthrus, 
the Crustacea Nebalia, Mysis, A pseudes, etc., and the insect Machilis— 
as has been done in a paper soon to be published in the Journal of the 
N. Y. Ent. Soc., 1921. When one studies such a series, it becomes 
apparent that the gnathobase region of the basal segment of the trilobites 
limb becomes differentiated into a biting region and a grinding region 
as we pass through the series of Crustacea mentioned above, and the 
biting region become the incisor region bearing the ‘“‘teeth”’ for cutting 
food, while the grinding region (which projects quite markedly in some 
