226 Mosquitoes 



8. Saddles of chitin on seventh and eighth seg- 



ments. Single tuft near middle of tube. 

 (Fig. 38, page 190.) . . . .Pncumaculex signifer. 

 Saddles of chitin absent. No tuft present on 

 tube, which is sparsely covered with long, 

 single hairs. The two ventral gills spatulate, 

 well developed, the dorsal pair about one-third 

 as long, pointed Wyeomyia smitliii. 



9. Chitin of head produced laterally into a promi- 



nent angle caudad of and extending laterad 

 of the base of the antennae, continued ventrad 

 into a sort of trough in which may be seen 

 protruded the outer portion of the mandible, 

 produced, like a glove thumb, and heavily 

 spined. Anal gills very little developed ; body 

 transparent, almost white. 



Deinocerites cancer. 



Chitin of head not produced as above; posterior 



portion of mandible never produced nor 



visible from above 10 



10. Anal gills three times as long as tube, with six 



or more constrictions. Bunches of tracheoles 

 in gills. Antennae shorter than head, straight. 

 Eighth segment comb in one row. (Fig 37, 



page 186.) Odderotatiis duprcci. 



Anal gills never three times as long as tube, 

 never with more than four distinct constric- 

 tions 11 



II. Mouth brushes of a few heavy bristles directed 

 outward at right angles to head, or folded 

 under. Antennae near middle of side of head. 

 Comb scales in a single row ; tuft of breathing 

 tube represented by one or two hairs. Larva 



very large 12 



Mouth brushes of slender hairs directed forward. 

 Antennae situated far forward. Larva small 

 or moderately large 13 



