40 



MR. K. M. SMITH ON CERTAIN SEKSEORGANS 



Oecidomyid^. 



I have been unable to examine any of these insects mj'self, but 

 Felt (3) describes the peculiar looped haiis or circumfili on the 

 antennsB ; he compares them to the "apparently fleshy hypo- 

 dermal structures protruding from relatively large symmetrically 

 placed orifices on the antenna! segments of Campy lomyzariinaj 

 and of certain Chironomids." As I have not been able to 

 examine any Cecidomyidse I cannot speak with certainty, but 

 possibly Felt is not quite correct in describing these processes 

 as " fleshy hypodermal structures protruding from relatively 

 large symmetrically placed orifices." What he takes for an 

 orifice may be the sudden change from the thick chitin of the 

 antennal sui-face to the excessively thin chitinous outpushing, 

 which is comparable to one of the sensory processes of a sense-pit 

 enormously enlarged. This sudden change from very thick to 

 very thin chitin certainly gives the impression of an orifice, but 

 under a high power it will be seen at once not to be so. 1 have 

 not found any of these very lai-ge chitinous processes in the Chiro- 

 nomids, but they are very evident in the Psychodidse (see above). 



Text-figure 5. 



Text-figure 6. 



Text-fig. 5. — Longitudinal section through the first and second joints of the 



palp of an undetermined Mycetophilid. X 980. 

 Text-fig. 6. — Another view of the same. X 980. 



