1. Geography, ecology and coexistence in relation to the biological definition of the species;Cain;Evolution,1953
2. Hand pairing of Papilio machaon in February;Clarke;Ent. Rec.,1952
3. Further observations on hybrid swallowtails;Clarke;Supp. Ent. Rec.,1953
4. Larva of P. brevicauda;Edwards;Can. Ent.,1874
5. Comments on Dr. Hagen's paper in Nov.-Dec. No. of Papilio, on P. machaon etc;Edwards;Papilio,1883