138 CALIFORNIA ACADEMY OF SCIENCES. 



anterior angles of the clypeus, in the female barely pro- 

 duced beyond the margin; strong, obtusely toothed man- 

 dibles ; labium with short but distinct apraglossae with 

 five short spines on tip of each; antennae similar in both 

 sexes; abdomen turbinated, with dark lateral bands and 

 brown transverse bands. 



Giebelia (nov. gen.) mirabilis n. sp. (Plate xi, figs,. 7 

 and 8.) 



Four males and five females taken from six out of seven 

 individuals of the Black-vented Shearwater, Pujjinus o-pis- 

 thome/as, shot on the Bay of Monterey, California. The 

 only species of Giebelia yet found. 



Description of the male. Body, length 1.28 mm., 

 width .56 mm.; short, broad (abdomen six-sevenths as 

 broad as long) ; pale ferrugineous with dark brown to 

 black markings; abdomen with strongly colored lateral 

 bands and paler transversal bands. 



Head, length, .45 mm., width .45 mm.; front broad, 

 truncate with very narrow uncolored margin ; one short 

 hair in anterior angle; on lateral margin in front of pro- 

 jecting transparent flap two short hairs; lateral projecting 

 part of crescentic, transversal, transparent flap as long 

 as from anterior margin of flap to anterior angle of cly- 

 peus; trabecular projecting as far as end of first segment 

 of antennce; antennae rather long, slender, segments 

 1-2 about equal, longest, segment 2 shorter, segment 4 

 shortest, segment 5 almost as long as segment 2, all 

 segments concolorous with head; sutures broadly un- 

 colored; hind head broadly quadrangular; temporal mar- 

 gins subparallel with angulated anterior angles produced, 

 and the large eye with a spine set at the angle; behind 

 the eye a very short hair; farther back a short hair, and 

 then two very long hairs; occipital margin straight, 



