OF MAXILLUL.fi IN THE ORDERS OF INSECTS. 



443 



Homologous though reduced structures were found in Dascillus. These 

 again were represented in a further reduced condition in the larva of the 

 Lamellicorn Geof.rupes. In a similar situation on the left side of the hypo- 

 pharynx of the larval Phyllopertlia occurred a very small lobe bearing teeth, 

 a scarcely recognisable maxillula. In each of these cases it appears that the 

 hypopharynx is membranous and is supported by a system of chitinous 

 sclerites. It covers almost the whole of the surface of the labium to which 

 it is fused or sutured in front. Of a totally different character is that of 

 the larval Pterosticlius described by Carpenter (7. p. 213, fig. 6). The 

 anterior border is here broad transversely, set with long setae and not united 

 to the labium. Where this border comes into close proximity to the base 

 of the maxilla it bears a small setose projection. This is regarded as a 



Text-fig. 10. 



Nebria brevicollis. Hypopharynx and labium, dorsal aspect. X 90. 

 h. Hypopharynx-. I. Labium, m. Maxillula (left). 



maxillula, agreeing as it does in position with the process described by 

 Magan (1912) in larval Dytiscidse. 



This latter type of hypopharynx I have found to occur in a modified form 

 in larv.se of Staphylinidse, Elateridse, and the Malacoderm Teleplwrus litur- 

 atus. In other larvas examined, Coccinellida?, Tenebrionida?, C'hrysomelida?, 

 CerambycidEe, and Ourculionidse, the structure was of the soft membranous 

 character supported by sclerites. In the former group the labium extended 

 considerably beyond the hypopharynx, and was not fused therewith anteriorly 

 as was the case in the latter group. 



33* 



