REPORT OF THE STATE ENTOMOLOGIST I904 



495 



Fig. 



Corethrella brakeleyi, ventral aspect of larval 

 head, much enlarged (Original) 



larger. Eucorethra is somewhat more highly specialized, the 

 antennae being markedly different in the two sexes and with 

 oblique scales present along the posterior margin of the female 

 wing and absent in that of the male. The species of Corethra 

 exhibit well marked sexual differences and may be instantly recog- 

 nized by the unique, very short first tarsal segment. The Sayomyias 

 present a some- 

 what general 

 resemblance to 

 the Corethra s, 

 though they 

 are easily dis- 

 tinguished on ac- 

 count of the first 

 tarsal segment 

 being longer than 

 the others. The 

 male genitalia of 

 these genera agree 

 substantially in 

 possessing rela- 

 tively simple clasp segments and with a single pair of subsidiary 

 organs, probably the harpes. 



The larvae of this group present marked structural differences. 

 That of Corethrella is exceedingly peculiar and may be considered 

 a divergent synthetic form. The head is armed laterally with 

 oblique rows of stout spines not seen in any other culicid larva, and 

 the rather broad, stout air tube is peculiar because its tracheae are 

 simple and open in well separated spiracles at the extremity of the 

 tube. The larva of Eucorethra likewise has independent tracheae 

 and on accoiuit of its surface-feeding habit possesses a short air 

 tube and in a general Avay resembles a giant Anopheles larva, though 

 with no trace of the characteristic comb of the latter. Corethra 

 larvae are interesting because they possess a rudimentary air tube 

 with well marked tracheal dilations or air reservoirs in the enlarged 

 thoracic and eighth abdominal segments. The Sayomyia larvae 

 are most peculiar. They have no vestige of an air tube and are 

 remarkable because of their extreme transparency, the only color 

 being the dark mouth parts, the black eyes and pigmented air sacks 

 in the thoracic and eighth abdominal segments. The larval mouth 

 parts of this genus are very different from those of the other genera 

 associated therewith. 



