Miss Tarango’s shriek attracts people from all over the school, including Mr. Barker. He gasps in horror at the bugs, living and dead, all over the room. As he starts to growl for the boys to tell him who did this, he stops short and shouts at Scobie to get the tarantula off his face. Calmly, Scobie says it’s a harmless Mexican bird-eating spider, but he takes off his glasses and the spider. He corrects Mr. Barker that spiders aren’t actually insects, which only infuriates Mr. Barker further.
Scobie correcting Mr. Barker is humorous for readers—but it also illustrates just how unafraid he is of the insects and spiders in the classroom. He’s far more concerned with correctly identifying the creatures than he is in escaping them, for instance. It seems likely that Scobie’s pedantic behavior is as much a show for Barry than anything else.
Mr. Barker asks where the insects and spiders came from. Scobie says they came from his desk, but they’re not his and he doesn’t know how they got there. Mr. Barker suggests someone put the creatures there as a joke. Scobie agrees that someone else put them there. He stares at Barry for a moment, but he says he doesn’t know who did it and doesn’t want to unfairly accuse anyone. Mr. Barker asks everyone to open their desks and bags. He finds shoeboxes, jars, and paper bags in Barry, Danny, and Doug’s desks.
Scobie (and, recall, everyone else in the classroom) knows exactly who’s responsible for putting the bugs in the desk. Nobody else is willing to speak up because they fear what Barry will do in retaliation. Scobie, though, very cleverly refuses to rat Barry out, in the name of fairness and justice. He trusts that Barry will get his comeuppance; he doesn’t need to humiliate Barry any further right now.