192 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



latus seems to indicate a different structure ?). I found both species in 

 the same situation, walking in numbers on the leaves of low shrubs. 



Family CECIDOMYID^. 



Of the numerous galls of Cecidomyice observed by me in California, 

 I will mention only a few, of which I have kept a written record. 



On Juniperus californicus, fleshy, subglobular galls on the axis of 

 the small twigs; when full grown, about two-fifths of an inch in diame- 

 ter, with a round opening at the top, the edge of which is from three- to 

 five-lobed, the gall when ripe thus resembling the fruit of the Medlar 

 (Mespilus) in shape; but, before being full grown and open, it is more like 

 a diminutive melon or tomato, being furrowed longitudinally, like these 

 fruits. The furrows are usually six, probably representing six leaves 

 round the axis of the plant. At the base of the gall, round its attach- 

 ment, there are three sepal-like, small, fleshy, bilobed leaflets. The 

 reddish larva in the cavity of the gall is smooth, and shows no vestige 

 of a breast-bone; in more mature galls, the pupa, glued to the bottom 

 of the cavity, could be distinctly seen through the opening at the top. 

 Very common in March, 1876, about Crafton's Retreat, twelve miles 

 from San Bernardino, Oal. 



On Litmus albifrons; folded leaves, forming a pod-shaped swelling; 

 each contained several larvae, inclosed in a delicate cocoon. Very com- 

 'mon about Lone Mountain, San Francisco, in April. 



On Audibertia sp. (Composite)) swelling on leaves and leaf-stalks, 

 with a neck-shaped prologation, open at the top, the whole having the 

 shape of a round-bellied bottle ; sometimes two or three such bottles, 

 alongside of each other, coalescent ; inside a longitudinal canal, at the 

 bottom of which I found in several instances a pupa of Cecidomyia; 

 wings and thorax blackish; abdomen red; no horny projections ante- 

 riorly. A small Hymenopterous parasite often infests this gall. Santa 

 Barbara, end of January, and later in other localities ; not rare. 



On Gdrrya fremonti, succulent, green swellings on male flowers, con. 

 tain larvae and pupae apparently of a species of Asphondylia. On the 

 heights about Yosemite Valley, at an altitude of 7,000 to 8,000 feet, in 

 June. 



On Artemisia califomica (?), accumulation of leaves, produced by the 

 arrested growth of lateral shoots. About Los Angeles, Cal. Inside I 

 found pupae of Cecidomyia, nearly ripe, on the 3d of March. 



On Baocharis pilularis (syn. sanguinea), rounded accumulation of de- 

 formed and swollen leaves at the end of twigs; contains larvae of 

 Cecidomyia, from which I bred the fly. 



Family MYGETOPHILITLF. 



Seems abundantly represented in California, although I did not collect 

 very diligently in it. Among my few specimens, I find the following- 

 genera: — 



