Key to species of the genus Streetsia Stebbing, 1888

1. Pereopod 6; basis with posterior margin produced into sharp lobe distally, projecting well beyond ischium. Gnathopod 2 of mature females; basis with postero-distal corner produced into rounded lobe................ S. challengeri Stebbing, 1888

- Pereopod 6; basis with posterior margin produced into rounded lobe distally, rarely projecting much beyond ischium. Gnatho- pod 2 of mature females; basis with normal postero-distal corner, not produced..................................... 2

2. Double urosomite almost twice as long as wide, or longer..................................................... 3

- Double urosomite about as long as wide.................................................................... 4

3. Gnathopod 2; carpal process produced to base of dactylus. Epimeral plates without noticeable cuticular pore......................................................................................... S. steenstrupi (Bovallius, 1887)

- Gnathopod 2; carpal process only reaching to about 0.7 x length of propodus. Epimeral plates with large, central cuticular pore.......................................................................... S. mindanaonis (Stebbing, 1888)

4. Gnathopod 2; carpal process with distal margin serrate..................................... S. porcella (Claus, 1879)

- Gnathopod 2; carpal process with distal margin armed with strong teeth............... S. palmaspinosa Vinogradov, 1990