124 
Psyche 
[December 
Lateral abdominal hairs triple on segments three to five ; 
scale of comb with a fringe of spines of approximately 
equal length: _____ 1 senior hynchus 
17. Air tube at least four times as long as wide : _ fitchii 
Air tube three times or less as long as wide 18 
18. Head hairs single 19 
Head hairs double or multiple 21 
19. Anal gills at least as long as anal segment 20 
Anal gills much shorter than anal segment: dorsalis 
20. Scale of comb with broad apex bearing four to seven 
stout spines : communis 
Scale of comb with single stout spine : impiger 
21. Both pairs of dorsal head hairs multiple 22 
Both pairs of dorsal head hairs not multiple 23 
22. Anal gills budlike ; found in salt water : cantator 
Anal gills well developed : canadensis 
23. Lower head hairs double, upper triple hirsuteron 
Lower head hairs single, upper double : stimulans 
Key to the Genus Theobaldia 
Adults 
1. Tarsi with poorly defined yellowish white rings at both 
ends of some of the joints : morsitans 
Tarsi without rings on any of the joints 2 
2. Scales of the wings mixed, black or brown and white 
especially along the costal margin; proboscis with 
intermixed black and white scales : inornata 
Scales of the wings all brown or black 3 
3. Mesonotum brown marked with yellowish lines or spots ; 
wings with some of the scales slightly aggregated 
along the third vein ; a large species : impatiens 
Mesonotum entirely reddish brown ; wing scales normal ; 
each abdominal segment with an apical row of coarse 
yellow hairs; a small species (4 mm.) : melanura 
Larvse 
1. Pecten produced into long hairs on outer half (Fig. 13) 
2 
Pecten not produced into long hairs on outer half 3 
c 
