84 Annals Entomological Society of America  [Vol. XIV, 
the posterior tentorial invaginations, according to Riley, 1904, in the 
embryo of the ceckroach. 
The membrane at the base of the maxilla, labeled ‘‘bm”’ in Fig. 5, 
etc., may be termed the basimavillary membrane. <A plate called the 
basimavwilla, ‘‘bm,”’ of Figs. 8, 9, etc., results from the chitinization and 
pigmentation of the membranous region at the base of the maxilla in 
certain coleopterous larve, etc. This basimaxillary plate, ‘‘bm,” of 
Figs. 8 and 9, should not be confused with the subdivision of the cardo 
labeled “pac” in Figs. 5, 6, ete., smce thelatter sclerite, “pac,” 1s\ a 
demarked subdivision of the cardo, and therefore does not arise through 
a greater deposition of chitin and pigment in the membrane at the 
base of the maxilla, as is the case with the basimaxillary plate. 
As was pointed out in a paper dealing with the maxillee of orthopteroid 
insects (Crampton, 1916) the basal sclerite or cardo of the maxilla of 
the insect shown in Fig. 10, for example, is divided into a eucardo, 
‘euc,’’? and a paracardo, ‘‘pac,’’ while the stipes, or second segment of 
the maxilla, is divided into a eustipes, “‘eus,’”’ and a parastipes, ‘‘pas.”’ 
The parastipes, ‘‘pas,’’ however, 1s apparently a distinct narrow sclerite 
formed along the mesal margin of the stipes, and it is doubtful that it 
‘ 
arose as a demarked portion of the stipes proper. In fact, it would. 
appear from a comparison with the structures of certain Crustacea, 
that the parastipes, ‘‘pas,’’ originally was a part of the basal segment or 
cardo, and become secondarily united with the stipes, but 1t is simpler to 
treat of the parastipes as a portion of the stipes. 
In a paper which will be published in the 1921 volume of the Pro- 
ceedings of the Ent. Society of Washington, it has been pointed out 
that the maxilla of a larval neuropteron such as the one shown in Fig. 23, 
corresponds in a remarkable fashion to the typical crustacean limb 
represented by the maxilliped of Gammarus (an amphipodan crustacean) 
for example, since in both cases, the mouthpart-limb 1s composed of 
seven segments, and the correspondence in the relative sizes of the 
individual segments, and the processes they bear, is marvellously close, 
when one takes into consideration the fact that we are dealing with 
forms belonging to distinct classes of arthropods. Such a comparison 
of the parts in insects and Crustacea very clearly demonstrates that the 
basal segment or cardo, ‘‘car,”’ of Fig. 23 represents the basal segment, or 
coxopodite, of a crustacean limb. The second segment, or stipes, 
“bs,” of Fig. 23, which bears a median process, ‘‘la,”” (the lacinia) 
in the insect there figured, clearly corresponds to the second segment or 
basipodite which also bears a median process or endite in a crustacean 
mouthpart-limb. The third segment, or palpifer, ‘‘ds,” of Fig. 23, 
which bears a median process, ‘‘ga,’’ (the galea), evidently corresponds. 
to the third segment or ischiopodite, which also bears a median process 
or endite in the crustacean mouthpart-limb. The four segments of the 
maxillary palpus, ‘“‘mp,”’ of Fig. 23, correspond (even to the relative’ 
lengths of the component segment) very closely to the four segments 
of the endopodite of the maxilliped or Gammarus, and there can be no 
doubt that the maxillary palpus of an insect’s maxillary appendage 
corresponds to the endopodite of a crustacean limb, while the palpifer 
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