220 



PSYCHE. 



[May— July 1SS9. 



RED OAK {^uercus r libra). 

 Amphibolips cookii n. sp. 



Galls (Fig. 6) globular, with a cen- 

 tral larval cell held in place by stout 

 radiating fibers. When green, the galls 

 resemble very much the growing galls 

 of Amphibolips inanis O. S. The 

 gall differs from that of A. inanis by 

 having a thicker outer shell, by having 

 much stouter radiating fibres, by being 

 somewhat drawn out into a point at 

 either extremity, and by occurring on the 

 buds instead of the leaves. The galls 

 fall with the leaves or before them, and, 

 when dried, the outer surface is much 

 shrivelled in appearance. About a pint 

 of these galls were gathered, some late 

 in the fall and others early in the spring, 

 under a large red oak. On cutting into 

 these galls the first day of September 

 following, five fully developed flies and 

 one pupa were found, all females. 



Fig. 6. 



Gall-fly : Head small ; clypeus and 

 jaws punctate ; vertex, occiput, and 

 median line of front coarsely pitted 

 or sculptured ; genae and sides of the 

 face deeply rugose, the furrows spread- 

 ing out like a fan from either side of 

 the clypeus ; entire head jet black and 

 rather thinly set with a grayish pubes- 

 cence, except on the vertex, where it 

 is bare. Jaws black ; palpi brown. 

 Antennae reach the middle of the abdo- 

 men ; 13-jointed , third joint longest; 



joints 3-13 gradually shorter; 13th joint 

 next to the third in length and as long 

 as the iith and 12th together. Thorax 

 entirely black. Parapsidal grooves pres- 

 ent but very indistinct and can be 

 traced about one-third of the way from 

 the scutellum to the collar. Between 

 and a little in front of these grooves arise 

 two parallel black ridges that appear as 

 mi)iute shiny lines which extend forward 

 to the collar. Two other similar lines 

 start midway on the thorax a little out- 

 side of the parapsidal grooves near the 

 base of the wings and extend back to 

 the scutellum. Thorax and scutellum 

 deeply sculptured and sparsely set with 

 short gray hairs. Scutellum with two 

 large fovae at the base separated by a 

 narrow septum ; subquadrangular in 

 outline and rounded and elevated pos- 

 teriorly. Abdomen varies from a very 

 dark amber to almost black ; segments 

 densely and finely jDunctate when exam- 

 ined with a power of 20 diameters ; 

 lateral portions of second segment very 

 sparsely pubescent. Legs dark amber 

 in color except the tips of the tarsi 

 which are black ; finely pubescent 

 throughout ; coxae black. Wings seven 

 to eight mm. in length ; somewhat 

 smoky, and with a large stigmal spot at 

 the base of the marginal cell. Length 

 of body five and one half mm. 



The following is a list of the cynipi- 

 dous galls taken in the vicinity of the 

 Michigan agricultural college. I have 

 in each case given the variety of oak 

 upon which they were taken, the date 

 that the flies emerged, when reared, 

 and the guests and parasites reared 

 from the different species : 



