OF WASHINGTON, VOLUME XIX, 1917 91 



Each thoracic and abdominal segment has dorsally at each side of the 

 middle a low, transverse elevation surmounted by a transverse row of 

 four or five short, stout, backward pointing spines. The mesothoracic, 

 metathoracic, and first eight abdominal segments bear spiracles. Those 

 of the mesothorax are situated in the intersegmental skin between the 

 prothorax and mesothorax, apparently on the prothorax. Those of the 

 metathorax are rudimentary and nonfunctional, and are, like those of the 

 abdominal segments, situated near the anterior margin of the segment. 

 The larva is legless, but the positions of the legs are indicated by chitinized 

 disks. 



PUPA OF Oryssus occidental i'.^. 



(Descriptions drawn from alcoholic specimens.) 



Female. Uncolored. In general the head, thorax and base of abdomen 

 resemble the adult but the most striking difference occurs in the ovipositor 

 and sheath which is curved up over the back and reaches the anterior mar- 

 gin of the head. Head much as in adult, even to the definition of the 

 tubercle's around the ocelli; the pupal skin enclosing the antennae obscures 

 the joints but from what can be seen the ninth is not abnormally swollen 

 and is connected with the tenth by its entire apical width; tarsi jointed as 

 in adult ; thorax much the same as to the sutures (these not well defined in 

 adult); the straight suture separating the scutum and scutellum, which is 

 strong in the adult, is weak in the pupa and the suture dividing the scu- 

 tellum, which is weak in the adult, is strong in the pupa. Abdomen with 

 seven well defined, visible tergites, the first not divided, the eighth tergite 

 smaller than the seventh; ninth tergite represented dorsally as a narrow 

 plate but produced anteriorly and ventrally; tenth tergite not clearly 

 defined but probably represented at the apical end of the ninth as a trans- 

 verse plate; second to eighth tergites, inclusive, with a series of fleshy 

 protuberances surmounted by transverse rows of spines near apical lateral 

 margin. First sternite concealed, the six following well defined, the 

 second nearly covered by hind coxae, the remaining uncovered and visible; 

 eighth and ninth sternites not visible except as represented by their ap- 

 pendages; tenth sternite not visible externally; pleural fold fleshy. The 

 external portion of the ovipositor as described above; internally it extends 

 forward into the mesothorax where it makes a simple loop. 



The following are the most striking differences between the 

 female pupa and adult. 



1. Ninth antennal joint normal. 



2. Scutum without lateral sutures. 



3. Accessory suture of scutellum strong. 



4. Suture between scutum and scutellum weak. 



5. Tergites with fleshy protuberances. 



tt. Apical tergites and sternites different. 

 7. Ovipositor curled up over the back. 



