64 H. F. BASSETT. 



aud second taken together. Thorax black, covered with fine, sliort hairs, evenly 

 punctate, parallel lines distinct and reaching: half way to the scutelluni : parap- 

 sidal grooves distinct and reaching three-fourths of the way to the collars ; lines 

 over the base of the wings distinct and closely approaching the parapsides ante- 

 riorly ; scutellum rugose, and with fine short hairs; no foveie, but a straight, 

 prominent, trausverse ridge separates the scutelluni from the mesonotum. ^46- 

 domen clear, semi-translucent browu, but unevenly shaded. Legs pale brown, 

 almost yellow. Wings heavily, but unevenly clouded, and with a small clear 

 spot in the middle of the radial area; veins heavy, dark browu, almost black: 

 areolet large, distinct; radial area "open, or but partially closed. Length : body, 

 11 inch. ; wings, .11 inch. ; autennse, .09 inch. 



HOL,€ASPIS Mayr. 

 1. H. duricoria n. sp. 



Galls. — Globular, but less regularly so than H. globulus Fitch ; 

 sessile and subclasping on the young branches of Q. hicolor. The 

 flattened base and the cone-like form of many of these galls remind 

 one of the Minnie rifle ball. They are often so crowded that they 

 become strangely misshapen ; the surface is finely pulverulent, and 

 when dry it is very hard. This suggested the trivial name. Inter- 

 nally the substance is similar to, but much harder than that of H. 

 globulus. The larval cell is free in a small, irregular cavity ; the 

 galls average one-half inch in diameter, and the oval larval cell is 

 one-eighth liy three-sixteenths inches. 



They are sometimes found in countless numbers on a single tree and 

 for a single season, and then nearly or quite disappear. A few galls 

 of this species appeared several years ago on a large and thrifty oak 

 {Q. bicolor). which is growing in the yard of one of my neighbors. 

 The next year the tree was covered witli them ; there were bushels 

 of them, but the year following there were few, if any, new galls, but 

 this year they have appeared again in considerable numbers. lu this 

 instance, and a few others, I have noticed that the tree .seemed to be 

 quite seriously injured by them. It is well known that this species 

 has a large number of jiarasitic enemies, else it might pi'ove very 

 destructive to this species of oak. It has other foes besides insect 

 parasites. 



This is an agamous species, and I flattered myself that the tree in 

 ray neighbor's yard would give me an excellent opportunity to study 

 the habits of these female flies as they left the galls, which they do 

 in October and November. 



I went day after day to look for them, but found only now and 

 then one on the {)alings of the fence enclosing the yard. At length 



