Grade 1-3--The title is one of the four sto ries in this book that continues the ad ventures of second-grade Horrible Har ry, previously seen in Horrible Harry in Room 2B (1988), and Horrible Harry and the Green Slime (1989, both Vi king). Short chapter books for readers graduating from beginning readers are welcome, and this series has been an enjoyable addition. But Class 2B, scene of Harry's adventures, may be a bit confusing to newcomers at first, as Kline barely introduces her narrator and characters. Previous fans, how ever, will enjoy another meeting with Harry and pals in these lighthearted outings, although Harry's horribleness is not very convincing. The title story concerns the arrival of ants to the class room and Harry's temporary loss of his position as "Ant Monitor" because he is bitten while locating a couple of es caping ants. The last story lacks any horridness or even much point, unless who you stand next to in a class picture really counts. Well-placed line draw ings extend the humor with lively rendi tions of this familiar cast of charac ters.