234 Annals Entomological Society of America  [Vol. V, 
furrow with lighter intervening parts. It is likely that this 
oblique, clear area distad of the ridge marks the distal limit of 
the stipes. This would make the union between the stipes and 
galea an oblique one with the maxillary palpus attached to the 
distal prolongation of the stipes. A similar condition will be 
noted in the other maxille figured. The furrow extending 
across the maxilla is the limit of the-distal part of the maxilla 
that is folded under the labium. If this ridge be considered as 
the suture between the stipes and the galea, it would place the 
maxillary palpus on the galea, which is an impossible interpre- 
tation in the light of the other maxille studied. In the more 
specialized Hymenoptera, wasps and bees, there is a cuticular 
membrane connecting the maxilla and the labium, which serves 
to close the mouth cavity on the ventral side. The distal edge 
of this membrane is attached to the stipes near the proximal end 
of the lacinia. This membrane is particularly well marked in 
mounts of the entire maxilla and labium of Bombus. In such 
mounts, the lacinia can be identified as a round lobe with long 
sete on its distal and lateral margins. It is placed adjacent to 
the distal margin of the membrane extending from the maxilla 
to the labium and is attached to the mesal margin of the stipes 
near its distal end or to the uncolored area of the stipes. This 
lobe is so distinct, once it has been seen, it is hard to understand 
how it has remained undescribed for so long. The lacinia, 
while showing distinctly in specimens mounted in balsam, can 
be studied to better advantage on maxille that have been 
cleared in caustic potash and examined in a watch glass in 
alcohol. 
Insect morphologists have been fairly uniform in their 
statements regarding the lacinia in the honey bee, A pis mellifica 
(Fig. 9). All the more important text-books on entomology 
figure a maxilla of Bombus or A pis, but without indication of the 
lacinia. The following quotations are typical for the maxilla 
of Apis. Comstock and Kellogg* describe these parts as 
follows: 
‘‘Sttpes. The stipes is an irregular, elongate sclerite, 
strongly chitinized. Its proximal end is bluntly rounded and 
swollen. The stipes articulates with the proximal segment of 
the galea (see below) by a diagonal face. 
*Comstock, John Henry and Kellogg, Vernon L. The elements of insect anat- 
omy. Ithaca. 1901. Pp. 78-79. 
