ih sie 
1880.] 399 (Patton. 
Phila., vi. p. 51, 52), who claims that the side lobes do not belong to 
the clypeus, but are ‘‘ submandibular pieces,” and belong to the 
epicranium, and who applies the term “foramina” to the foveae 
notwithstanding that there is no perforation. In arguing for the 
distinctness of the side lobes from the presence of the short suture 
between the lobes of the clypeus in Cerceris, Dr. Packard has en- 
tirely misunderstood the nature of these sutures, and overlooked the 
fact that the clypeus of Philanthus does not differ greatly from that 
of the Larradae and certain Sphecidae, and that Cerceris is the most 
specialized genus. 
In regard to the foveae, it may be stated that they indicate points 
of attachment for the endocranium or inner skeleton of the head ; 
and that their analogues exist in other families of the Hymenoptera, 
and also in other orders of insects. In C. compar ¢ this inner skele- 
ton consists of two parallel rods attached at opposite sides of the 
occipital foramen, and extending to the suture over the side lobes of 
the clypeus. These rods are slightly flattened and twisted, and 
have their edges thickened. The anterior third of the rod is ex- 
panded into a curved plate, and the end of this plate is attached 
along the suture, from the mandible to the fovea. 
The mandibles of Cerceris, as described, are tridentate. An 
examination of many of our species shows much variation. The 
mandibles in the males of the greater number of species (including 
bicornuta, fumipennis, sexta, deserta, etc., fulvipes, clypeata) are with- 
out teeth, just as is the case with the mandibles in both sexes of 
Philanthus and Aphilanthops, and in the males of Lucerceris. In 
Eucerceris 2 the mandibles in the species examined have only one 
tooth on the inner side, and this tooth varies both in position and 
size according to the species. Most species of Cercerishave two or 
three small teeth near the middle or base of the mandibles in the 
female, and the arrangement and form of these teeth afford specific 
characters. C. compar Cress. and C. mandibularis Patton are 
peculiar for having a distinct tooth on the middle of the inner bor- 
der of the mandibles in the male, and for having the mandibles of 
the female much expanded within, near the middle, \and bearing 
upon this expansion the minute teeth found in other species of Cer- 
ceris. » It appears, therefore, that the tooth on the mandible of the 
male of those species is a vestige of this expansion. The male of 
C. insolita Cress. resembles C. mandibularis in having a small tooth 
on the mandibles. In C. compacta ¢ there is a large and sharp 
