ODONATA OF BAJA CALIFORNIA. 537 



cubital, this spot being usually cleft on its outer edge at 

 the basilar space. Pterostigma ochre-brown, membra- 

 nule brown. 



Teneral S resembles the $ in color of thorax and abdo- 

 men. 



$ (teneral). Yellowish. Tibiae, tarsi and lateral mar- 

 gins of abdominal segments 4-9 brown. Wilvar lamina 

 about as long as 9, projecting and forming with the abdo- 

 men an angle of about 40^, margin entire. Appendages 

 longer than 10, not as long as 9. Front wings pale yel- 

 lowish at base to the iirst antecubital, hind wings pale 

 yellowish for nearly their entire width from base to the 

 arculus. Pterostigma yellowish. 



$ (adult). Yellow of the teneral ? becomes brown. 

 Vulvar lamina forming an angle of 50^-60° with the ab- 

 domen — due to the extrusion of eggs? Extent of yellow 

 on base of the wings very variable, in some cases confined 

 to the extreme base. 



S ? Front wings with 9-11 antecubitals, 6-8 postcubi- 

 tals, discoidal triangle with one cross-vein, internal trian- 

 gle of 3 cells, 3 rows of post-triangular cells. Hind wings 

 with 7-8 antecubitals, 6-8 postcubitals, triangle free. 



Total length S 31-35-5, ? 29.5-32. Abdomen S 20-23, 



? 18.5-20.5. Hind wing $ 24-26, ? 24. Pterost. 3.5. 



Width of abdomen at 2 : 2, at 5: 2.3, at 8: 2, at 10: 1.3. 



This species seemed, judging from the descriptions of 

 Rambur and Hagen, to be T. ahjccta. Mr. Henshaw, 

 having compared a pair of basifnsca with specimens of 

 ahjecta in the museum at Cambridge, wrote "I should 

 consider Tritheiuis basifnsca a new species and different 

 from any in the M. C. Z. collection; both sexes differ 

 from the same of ahjecta in the proportionate length of 

 the wings and abdomen, in the general color of the body 

 of the ? and the amount and hue of coloring on the wings 



