THK UENUS DENDROCTONUS. 61 



lateral margins of the maxillary foramen. The anterior end supports 

 the fossa (g) of the ventral articulation for the mandible, and the 

 ventral end supports the condyle for the articulation of the maxillary 

 cardo. It is connected across the gular space by the entogular plate. 



Pleurostoma (fig. 40, e). The pleurostoma is represented by the 

 thickened lateral -margin of the oral foramen. The dorsal end con- 

 tributes to the rigid support of the dorsal articulation for the mandible 

 and the ventral end to that of the ventral articulation. 



Front. The front is situated posterior to the epistoma and between 

 oblique sutures which converge from the anterior angles to the 

 epicranial suture. The median area is quite variable within the genus. 

 It may be flat and smooth to elevated. In the latter case it may be 

 small, smooth, and convex, or prominent, transverse, and rugose. 



Epicranium. The epicranium is represented by the dorsal areas 

 of the two large lobes each side of the distinct epicranial suture and 

 frontal area. These lobes are continuous throughout the occipital 

 and genal areas and accommodate the very large retractor muscles 

 of the mandible. The genal areas are connected by the broad ento- 

 gular plate. 



Occipital foramen. The occipital foramen is situated in the pos- 

 terior ventral section of the head and occupies about one-half of the 

 ventral area. It is bounded posteriorly and laterally by a broad 

 entoccipital rim and anteriorly by a subchitinous rim. The occipital 

 apodeme arises from the posterior margin, and extends anteriorly 

 immediately beneath the epicranial suture. 



Entogular plate (fig. 40, i). The entogular plate is the subchitinous 

 plate which forms the entocranial connection between the genal areas 

 and anteriorly between the lateral sections of the hypostoma. It is 

 covered by the submental lobe, part of the muscles of which are at- 

 tached to the posterior angles and posterior margin. 



Maxillse (fig. 41). The maxillae are quite simple in structural 

 details. The cardo is present and distinct. Its basal articulation 

 and attachment are by ligaments and a fossa to a condyle supported 

 by the hypostomal apodeme. Its anterior attachment to the stipes 

 is by articulating membrane. The median section is not divided into 

 stipes, subgalea, and palpifer, but is one continuous piece with the 

 anterior inner angle produced into a lacinial lobe which is armed with 

 a number of papillae situated on a membranous integument. The 

 palpus is 2-jointed and telescopic as usual. The relative proportions, 

 sculpture, and vestiture are shown in the figure. 



Ldbium. The labium of the larva is very different in structure 

 from that of the adult. The submentum is represented by a lobe 

 which is very broad and differs but slightly from the sternal lobe of 

 the prothoracic segment with which its posterior integument is 

 directly connected. The lateral integument is continuous with that 



