108 [May. 



" tormae," which, in generalized insects,- " are the ehitinized pieces which 

 belong to the lateral portions of the epipharjnx in the region of the 

 clypeo-labial suture and connect it with the clypeus or labrum at 

 the lateral ends of the suture." Whether this expression is new or 

 otherwise is difficult to discover; it is absent from Gr. B. Smith's 

 standard glossary of entomological terms, and no reference is made 

 thereto in Berlese's " Gli Insetti." The tormae, it appears, project 

 anteriorly and unite with the fronto-clypeus in generalized Di^jtera, such 

 as Psorophora and Stratiomyia. In Cyclorrhapha the}^ are fused 

 (although sutures still persist) with the fulcrum. If this interpretation 

 be correct, the external or anterior portion of the latter (in the house-Hy, 

 for example) can no longer be homologized with the clypeus. The inter- 

 pretation of the clypeo-frontal region might be debated at length, but 

 there seems no probability of arriving at any stabilized conclusion drawn 

 from mor|)hology alone. Peterson, however, has done a distinct service 

 in bringing a fresh point of view to bear upon the subject, and it must 

 be left to the future to determine its accurac}^ or otherwise. 



The term basipharynx is used by him to include all the united 

 portions of the epi- and hypopharyiix, and it is of general occurrence 

 throughout the order. In the Calypterae the fulcrum, according to 

 Peterson, represents the fusion of the tormae with the basipharjnix. 

 The author deserves great credit for the care with which he has observed 

 and figured this chitinous supporting framework of the pharynx in a 

 large number of types, and I think I am correct in asserting that 

 a number of Dipterists have scarcel}' suspected its occurrence in the 

 Nematocera at all. 



With regard to the ptilinum, little that is new is embodied in the 

 paper. The structure and development of this organ offers a wide and 

 promising field for research. From an examination of a long series of 

 sections of Galllphora I have failed to detect any trace of the organ in 

 the fulh^-grown larv^a, and we have to look for its first ajipearance in the 

 ■early pupa. It is not at all clear whether it is primarily developed as an 

 invagination of the head — in fact, the evidence suggests its being an evagi- 

 nation which becomes withdrawn after the emergence of the imago. 

 Also, its presence or absence in that unnatui-al assemblage known as 

 the Achiza needs to be very carefully ascertained. The account of 

 the tentorium extends our knowledge of the cephalic endoskeleton very 

 considerably ; it has three pairs of arms and a reduced body, and the 

 primitive invaginations, or intra-cranial tunnels, persist to a greater or 

 less degree in most Diptera. 



