IIO CALIFORNIA ACADEMY OF SCIENCES. 



shortness of body. Head, length 5 mm., width .41 mm.; 

 more rounding than truncate in front and without colored 

 markings, except dark brown labium and pale brown 

 mandibles; ratio of breadth to length greater than in 

 adult. Thorax with a lateral small black blotch near 

 anterior angle of metathorax. Abdomen, length .81 mm., 

 width .41 mm.; without median markings, a small black 

 blotch at anterior angle of segments 1-7, blotches grow- 

 ing smaller in each succeeding segment. 



Nirmus felix Giebel. (Plate vi, figs. 3 and 4.) 



Iusecta Epizoa, 1874, p. 175. 

 Two specimens, both males, taken from two specimens 

 of Heerman's Gull, Larus hcermani (Bay of Monterey, 

 California), maybe attributed to this species of Giebel 

 established on a single female taken from the same species 

 of gull. Piaget (Les Pediculines, p. 201) assumes to 

 believe Giebel's specimen a variety oi punctatus. " Cette 

 spece ne me parait non plus qu'une varits|p du punctatus 

 ou l'occiput n'est pas borde de noir et les taches de l'ab- 

 domen sont plus allongees transversalement." But the 

 differences between the males taken by me and the male 

 punctatus are much more considerable than this. The 

 black bordering of the head and the strong tripartite 

 blotches of the abdomen remove it distinctly from any 

 immediate similarity with punctatus; in fact, the species 

 more nearly resembles lineolatus than punctatus (compare 

 figures 1, 3, 4, 7 and 8, plate vi). Its most striking re- 

 semblance, however, is to pra>stans, the transparent clyp- 

 eus, different abdominal markings and markedly different 

 male genitalia distinguishing it from pr&stans. 



Description of male. Body, length 3.66 mm., width 

 .62 mm.; white, with dark brown or black marginal 

 markings, and chestnut brown, median abdominal mark- 

 ings. 



